Programs & Examples On #Json

JSON (JavaScript Object Notation) is a textual data interchange format and language-independent. Use this tag when this text format is involved. DO NOT USE THIS TAG FOR NATIVE JAVASCRIPT OBJECTS OR JAVASCRIPT OBJECT LITERALS. Before you ask a question, validate your JSON using a JSON validator such as JSONLint.

Keep the order of the JSON keys during JSON conversion to CSV

Tested the wink solution, and working fine:

@Test
public void testJSONObject() {
    JSONObject jsonObject = new JSONObject();
    jsonObject.put("bbb", "xxx");
    jsonObject.put("ccc", "xxx");
    jsonObject.put("aaa", "xxx");
    jsonObject.put("xxx", "xxx");
    System.out.println(jsonObject.toString());
    assertTrue(jsonObject.toString().startsWith("{\"xxx\":"));
}

@Test
public void testWinkJSONObject() throws JSONException {
    org.apache.wink.json4j.JSONObject jsonObject = new OrderedJSONObject();
    jsonObject.put("bbb", "xxx");
    jsonObject.put("ccc", "xxx");
    jsonObject.put("aaa", "xxx");
    jsonObject.put("xxx", "xxx");
    assertEquals("{\"bbb\":\"xxx\",\"ccc\":\"xxx\",\"aaa\":\"xxx\",\"xxx\":\"xxx\"}", jsonObject.toString());
}

How to create correct JSONArray in Java using JSONObject

I suppose you're getting this JSON from a server or a file, and you want to create a JSONArray object out of it.

String strJSON = ""; // your string goes here
JSONArray jArray = (JSONArray) new JSONTokener(strJSON).nextValue();
// once you get the array, you may check items like
JSONOBject jObject = jArray.getJSONObject(0);

Hope this helps :)

Serializing an object to JSON

Just to keep it backward compatible I load Crockfords JSON-library from cloudflare CDN if no native JSON support is given (for simplicity using jQuery):

function winHasJSON(){
  json_data = JSON.stringify(obj);
  // ... (do stuff with json_data)
}
if(typeof JSON === 'object' && typeof JSON.stringify === 'function'){
  winHasJSON();
} else {
  $.getScript('//cdnjs.cloudflare.com/ajax/libs/json2/20121008/json2.min.js', winHasJSON)
}

Display curl output in readable JSON format in Unix shell script

A few solutions to choose from:

json_pp: command utility available in Linux systems for JSON decoding/encoding

echo '{"type":"Bar","id":"1","title":"Foo"}' | json_pp -json_opt pretty,canonical
{
   "id" : "1",
   "title" : "Foo",
   "type" : "Bar"
}

You may want to keep the -json_opt pretty,canonical argument for predictable ordering.


: lightweight and flexible command-line JSON processor. It is written in portable C, and it has zero runtime dependencies.

echo '{"type":"Bar","id":"1","title":"Foo"}' | jq '.'
{
  "type": "Bar",
  "id": "1",
  "title": "Foo"
}

The simplest jq program is the expression ., which takes the input and produces it unchanged as output.

For additinal jq options check the manual


with :

echo '{"type":"Bar","id":"1","title":"Foo"}' | python -m json.tool
{
    "id": "1",
    "title": "Foo",
    "type": "Bar"
}

with and :

echo '{"type":"Bar","id":"1","title":"Foo"}' | node -e "console.log( JSON.stringify( JSON.parse(require('fs').readFileSync(0) ), 0, 1 ))"
{
 "type": "Bar",
 "id": "1",
 "title": "Foo"
}

How can I convert JSON to CSV?

It'll be easy to use csv.DictWriter(),the detailed implementation can be like this:

def read_json(filename):
    return json.loads(open(filename).read())
def write_csv(data,filename):
    with open(filename, 'w+') as outf:
        writer = csv.DictWriter(outf, data[0].keys())
        writer.writeheader()
        for row in data:
            writer.writerow(row)
# implement
write_csv(read_json('test.json'), 'output.csv')

Note that this assumes that all of your JSON objects have the same fields.

Here is the reference which may help you.

How can I use JQuery to post JSON data?

I tried Ninh Pham's solution but it didn't work for me until I tweaked it - see below. Remove contentType and don't encode your json data

$.fn.postJSON = function(url, data) {
    return $.ajax({
            type: 'POST',
            url: url,
            data: data,
            dataType: 'json'
        });

Parse JSON object with string and value only

My pseudocode example will be as follows:

JSONArray jsonArray = "[{id:\"1\", name:\"sql\"},{id:\"2\",name:\"android\"},{id:\"3\",name:\"mvc\"}]";
JSON newJson = new JSON();

for (each json in jsonArray) {
    String id = json.get("id");
    String name = json.get("name");

    newJson.put(id, name);
}

return newJson;

How to export a MySQL database to JSON?

THis is somthing that should be done in the application layer.

For example, in php it is a s simple as

Edit Added the db connection stuff. No external anything needed.

$sql = "select ...";
$db = new PDO ( "mysql:$dbname", $user, $password) ;
$stmt = $db->prepare($sql);
$stmt->execute();
$result = $stmt->fetchAll();

file_put_contents("output.txt", json_encode($result));

Adding elements to object

For anyone still looking for a solution, I think that the objects should have been stored in an array like...

var element = {}, cart = [];
element.id = id;
element.quantity = quantity;
cart.push(element);

Then when you want to use an element as an object you can do this...

var element = cart.find(function (el) { return el.id === "id_that_we_want";});

Put a variable at "id_that_we_want" and give it the id of the element that we want from our array. An "elemnt" object is returned. Of course we dont have to us id to find the object. We could use any other property to do the find.

loading json data from local file into React JS

If you want to load the file, as part of your app functionality, then the best approach would be to include and reference to that file.

Another approach is to ask for the file, and load it during runtime. This can be done with the FileAPI. There is also another StackOverflow answer about using it: How to open a local disk file with Javascript?

I will include a slightly modified version for using it in React:

class App extends React.Component {
  constructor(props) {
    super(props);
    this.state = {
      data: null
    };
    this.handleFileSelect = this.handleFileSelect.bind(this);
  }

  displayData(content) {
    this.setState({data: content});
  }

  handleFileSelect(evt) {
    let files = evt.target.files;
    if (!files.length) {
      alert('No file select');
      return;
    }
    let file = files[0];
    let that = this;
    let reader = new FileReader();
    reader.onload = function(e) {
      that.displayData(e.target.result);
    };
    reader.readAsText(file);
  }

  render() {
    const data = this.state.data;
    return (
      <div>
        <input type="file" onChange={this.handleFileSelect}/>
        { data && <p> {data} </p> }
      </div>
    );
  }
}

How to convert JSON data into a Python object

This is not code golf, but here is my shortest trick, using types.SimpleNamespace as the container for JSON objects.

Compared to the leading namedtuple solution, it is:

  • probably faster/smaller as it does not create a class for each object
  • shorter
  • no rename option, and probably the same limitation on keys that are not valid identifiers (uses setattr under the covers)

Example:

from __future__ import print_function
import json

try:
    from types import SimpleNamespace as Namespace
except ImportError:
    # Python 2.x fallback
    from argparse import Namespace

data = '{"name": "John Smith", "hometown": {"name": "New York", "id": 123}}'

x = json.loads(data, object_hook=lambda d: Namespace(**d))

print (x.name, x.hometown.name, x.hometown.id)

Python No JSON object could be decoded

It seems that you have invalid JSON. In that case, that's totally dependent on the data the server sends you which you have not shown. I would suggest running the response through a JSON validator.

Problems with jQuery getJSON using local files in Chrome

Another way to do it is to start a local HTTP server on your directory. On Ubuntu and MacOs with Python installed, it's a one-liner.

Go to the directory containing your web files, and :

python -m SimpleHTTPServer

Then connect to http://localhost:8000/index.html with any web browser to test your page.

Convert normal Java Array or ArrayList to Json Array in android

ArrayList<String> list = new ArrayList<String>();
list.add("blah");
list.add("bleh");
JSONArray jsArray = new JSONArray(list);

This is only an example using a string arraylist

How to upload a file and JSON data in Postman?

If you are using cookies to keep session, you can use interceptor to share cookies from browser to postman.

Also to upload a file you can use form-data tab under body tab on postman, In which you can provide data in key-value format and for each key you can select the type of value text/file. when you select file type option appeared to upload the file.

Convert Pandas DataFrame to JSON format

To transform a dataFrame in a real json (not a string) I use:

    from io import StringIO
    import json
    import DataFrame

    buff=StringIO()
    #df is your DataFrame
    df.to_json(path_or_buf=buff,orient='records')
    dfJson=json.loads(buff)

Postgres: How to convert a json string to text?

An easy way of doing this:

SELECT  ('[' || to_json('Some "text"'::TEXT) || ']')::json ->> 0;

Just convert the json string into a json list

How do I write JSON data to a file?

if you are trying to write a pandas dataframe into a file using a json format i'd recommend this

destination='filepath'
saveFile = open(destination, 'w')
saveFile.write(df.to_json())
saveFile.close()

JSON encode MySQL results

$array = array();
$subArray=array();
$sql_results = mysql_query('SELECT * FROM `location`');

while($row = mysql_fetch_array($sql_results))
{
    $subArray[location_id]=$row['location'];  //location_id is key and $row['location'] is value which come fron database.
    $subArray[x]=$row['x'];
    $subArray[y]=$row['y'];


 $array[] =  $subArray ;
}
echo'{"ProductsData":'.json_encode($array).'}';

how to add key value pair in the JSON object already declared

Object assign copies one or more source objects to the target object. So we could use Object.assign here.

Syntax: Object.assign(target, ...sources)

_x000D_
_x000D_
var obj  = {};_x000D_
_x000D_
Object.assign(obj, {"1":"aa", "2":"bb"})_x000D_
_x000D_
console.log(obj)
_x000D_
_x000D_
_x000D_

Python: converting a list of dictionaries to json

response_json = ("{ \"response_json\":" + str(list_of_dict)+ "}").replace("\'","\"")
response_json = json.dumps(response_json)
response_json = json.loads(response_json)

How to convert JSON to string?

You can use the JSON stringify method.

JSON.stringify({x: 5, y: 6}); // '{"x":5,"y":6}' or '{"y":6,"x":5}'

There is pretty good support for this across the board when it comes to browsers, as shown on http://caniuse.com/#search=JSON. You will note, however, that versions of IE earlier than 8 do not support this functionality natively.

If you wish to cater to those users as well you will need a shim. Douglas Crockford has provided his own JSON Parser on github.

What is the difference between YAML and JSON?

From: Arnaud Lauret Book “The Design of Web APIs.” :

The JSON data format

JSON is a text data format based on how the JavaScript programming language describes data but is, despite its name, completely language-independent (see https://www.json.org/). Using JSON, you can describe objects containing unordered name/value pairs and also arrays or lists containing ordered values, as shown in this figure.

enter image description here

An object is delimited by curly braces ({}). A name is a quoted string ("name") and is sep- arated from its value by a colon (:). A value can be a string like "value", a number like 1.23, a Boolean (true or false), the null value null, an object, or an array. An array is delimited by brackets ([]), and its values are separated by commas (,). The JSON format is easily parsed using any programming language. It is also relatively easy to read and write. It is widely adopted for many uses such as databases, configura- tion files, and, of course, APIs.

YAML

YAML (YAML Ain’t Markup Language) is a human-friendly, data serialization format. Like JSON, YAML (http://yaml.org) is a key/value data format. The figure shows a comparison of the two.

enter image description here

Note the following points:

  • There are no double quotes (" ") around property names and values in YAML.

  • JSON’s structural curly braces ({}) and commas (,) are replaced by newlines and indentation in YAML.

  • Array brackets ([]) and commas (,) are replaced by dashes (-) and newlines in YAML.

  • Unlike JSON, YAML allows comments beginning with a hash mark (#). It is relatively easy to convert one of those formats into the other. Be forewarned though, you will lose comments when converting a YAML document to JSON.

POST JSON to API using Rails and HTTParty

The :query_string_normalizer option is also available, which will override the default normalizer HashConversions.to_params(query)

query_string_normalizer: ->(query){query.to_json}

how to parse JSONArray in android

Here is a better way for doing it. Hope this helps

protected void onPostExecute(String result) {
                Log.v(TAG + " result);


                if (!result.equals("")) {

                    // Set up variables for API Call
                    ArrayList<String> list = new ArrayList<String>();

                    try {
                        JSONArray jsonArray = new JSONArray(result);

                        for (int i = 0; i < jsonArray.length(); i++) {

                            list.add(jsonArray.get(i).toString());

                        }//end for
                    } catch (JSONException e) {
                        Log.e(TAG, "onPostExecute > Try > JSONException => " + e);
                        e.printStackTrace();
                    }


                    adapter = new ArrayAdapter<String>(ListViewData.this, android.R.layout.simple_list_item_1, android.R.id.text1, list);
                    listView.setAdapter(adapter);
                    listView.setOnItemClickListener(new OnItemClickListener() {
                        @Override
                        public void onItemClick(AdapterView<?> parent, View view, int position, long id) {

                            // ListView Clicked item index
                            int itemPosition = position;

                            // ListView Clicked item value
                            String itemValue = (String) listView.getItemAtPosition(position);

                            // Show Alert
                            Toast.makeText( ListViewData.this, "Position :" + itemPosition + "  ListItem : " + itemValue, Toast.LENGTH_LONG).show();
                        }
                    });

                    adapter.notifyDataSetChanged();
...

angularjs - ng-repeat: access key and value from JSON array object

try this..

<tr ng-repeat='item in items'>
<td>{{item.Name}}</td>
<td>{{item.Price}}</td>
<td>{{item.Quantity}}</td>
</tr>

Spring: return @ResponseBody "ResponseEntity<List<JSONObject>>"

Personally, I prefer changing the method signature to:

public ResponseEntity<?>

This gives the advantage of possibly returning an error message as single item for services which, when ok, return a list of items.

When returning I don't use any type (which is unused in this case anyway):

return new ResponseEntity<>(entities, HttpStatus.OK);

JSON parsing using Gson for Java

Simplest thing usually is to create matching Object hierarchy, like so:

public class Wrapper {
   public Data data;
}
static class Data {
   public Translation[] translations;
}
static class Translation {
   public String translatedText;
}

and then bind using GSON, traverse object hierarchy via fields. Adding getters and setters is pointless for basic data containers.

So something like:

Wrapper value = GSON.fromJSON(jsonString, Wrapper.class);
String text = value.data.translations[0].translatedText;

Retrieving values from nested JSON Object

Maybe you're not using the latest version of a JSON for Java Library.

json-simple has not been updated for a long time, while JSON-Java was updated 2 month ago.

JSON-Java can be found on GitHub, here is the link to its repo: https://github.com/douglascrockford/JSON-java

After switching the library, you can refer to my sample code down below:

public static void main(String[] args) {
    String JSON = "{\"LanguageLevels\":{\"1\":\"Pocz\\u0105tkuj\\u0105cy\",\"2\":\"\\u015arednioZaawansowany\",\"3\":\"Zaawansowany\",\"4\":\"Ekspert\"}}\n";

    JSONObject jsonObject = new JSONObject(JSON);
    JSONObject getSth = jsonObject.getJSONObject("LanguageLevels");
    Object level = getSth.get("2");

    System.out.println(level);
}

And as JSON-Java open-sourced, you can read the code and its document, they will guide you through.

Hope that it helps.

Setting Access-Control-Allow-Origin in ASP.Net MVC - simplest possible method

    public ActionResult ActionName(string ReqParam1, string ReqParam2, string ReqParam3, string ReqParam4)
    {
        this.ControllerContext.HttpContext.Response.Headers.Add("Access-Control-Allow-Origin","*");
         /*
                --Your code goes here --
         */
        return Json(new { ReturnData= "Data to be returned", Success=true }, JsonRequestBehavior.AllowGet);
    }

Can not deserialize instance of java.util.ArrayList out of VALUE_STRING

For people that find this question by searching for the error message, you can also see this error if you make a mistake in your @JsonProperty annotations such that you annotate a List-typed property with the name of a single-valued field:

@JsonProperty("someSingleValuedField") // Oops, should have been "someMultiValuedField"
public List<String> getMyField() { // deserialization fails - single value into List
  return myField;
}

Parsing JSON in Java without knowing JSON format

Take a look at Jacksons built-in tree model feature.

And your code will be:

public void parse(String json)  {
       JsonFactory factory = new JsonFactory();

       ObjectMapper mapper = new ObjectMapper(factory);
       JsonNode rootNode = mapper.readTree(json);  

       Iterator<Map.Entry<String,JsonNode>> fieldsIterator = rootNode.fields();
       while (fieldsIterator.hasNext()) {

           Map.Entry<String,JsonNode> field = fieldsIterator.next();
           System.out.println("Key: " + field.getKey() + "\tValue:" + field.getValue());
       }
}

Posting a File and Associated Data to a RESTful WebService preferably as JSON

I know this question is old, but in the last days I had searched whole web to solution this same question. I have grails REST webservices and iPhone Client that send pictures, title and description.

I don't know if my approach is the best, but is so easy and simple.

I take a picture using the UIImagePickerController and send to server the NSData using the header tags of request to send the picture's data.

NSMutableURLRequest *request = [[NSMutableURLRequest alloc] initWithURL:[NSURL URLWithString:@"myServerAddress"]];
[request setHTTPMethod:@"POST"];
[request setHTTPBody:UIImageJPEGRepresentation(picture, 0.5)];
[request setValue:@"image/jpeg" forHTTPHeaderField:@"Content-Type"];
[request setValue:@"myPhotoTitle" forHTTPHeaderField:@"Photo-Title"];
[request setValue:@"myPhotoDescription" forHTTPHeaderField:@"Photo-Description"];

NSURLResponse *response;

NSError *error;

[NSURLConnection sendSynchronousRequest:request returningResponse:&response error:&error];

At the server side, I receive the photo using the code:

InputStream is = request.inputStream

def receivedPhotoFile = (IOUtils.toByteArray(is))

def photo = new Photo()
photo.photoFile = receivedPhotoFile //photoFile is a transient attribute
photo.title = request.getHeader("Photo-Title")
photo.description = request.getHeader("Photo-Description")
photo.imageURL = "temp"    

if (photo.save()) {    

    File saveLocation = grailsAttributes.getApplicationContext().getResource(File.separator + "images").getFile()
    saveLocation.mkdirs()

    File tempFile = File.createTempFile("photo", ".jpg", saveLocation)

    photo.imageURL = saveLocation.getName() + "/" + tempFile.getName()

    tempFile.append(photo.photoFile);

} else {

    println("Error")

}

I don't know if I have problems in future, but now is working fine in production environment.

How to convert View Model into JSON object in ASP.NET MVC?

@Html.Raw(Json.Encode(object)) can be used to convert the View Modal Object to JSON

Angular get object from array by Id

// Used In TypeScript For Angular 4+        
const viewArray = [
          {id: 1, question: "Do you feel a connection to a higher source and have a sense of comfort knowing that you are part of something greater than yourself?", category: "Spiritual", subs: []},
          {id: 2, question: "Do you feel you are free of unhealthy behavior that impacts your overall well-being?", category: "Habits", subs: []},
          {id: 3, question: "Do you feel you have healthy and fulfilling relationships?", category: "Relationships", subs: []},
          {id: 4, question: "Do you feel you have a sense of purpose and that you have a positive outlook about yourself and life?", category: "Emotional Well-being", subs: []},
          {id: 5, question: "Do you feel you have a healthy diet and that you are fueling your body for optimal health? ", category: "Eating Habits ", subs: []},
          {id: 6, question: "Do you feel that you get enough rest and that your stress level is healthy?", category: "Relaxation ", subs: []},
          {id: 7, question: "Do you feel you get enough physical activity for optimal health?", category: "Exercise ", subs: []},
          {id: 8, question: "Do you feel you practice self-care and go to the doctor regularly?", category: "Medical Maintenance", subs: []},
          {id: 9, question: "Do you feel satisfied with your income and economic stability?", category: "Financial", subs: []},
          {id: 10, question: "Do you feel you do fun things and laugh enough in your life?", category: "Play", subs: []},
          {id: 11, question: "Do you feel you have a healthy sense of balance in this area of your life?", category: "Work-life Balance", subs: []},
          {id: 12, question: "Do you feel a sense of peace and contentment  in your home? ", category: "Home Environment", subs: []},
          {id: 13, question: "Do you feel that you are challenged and growing as a person?", category: "Intellectual Wellbeing", subs: []},
          {id: 14, question: "Do you feel content with what you see when you look in the mirror?", category: "Self-image", subs: []},
          {id: 15, question: "Do you feel engaged at work and a sense of fulfillment with your job?", category: "Work Satisfaction", subs: []}
    ];

         const arrayObj = any;
         const objectData = any;

          for (let index = 0; index < this.viewArray.length; index++) {
              this.arrayObj = this.viewArray[index];
              this.arrayObj.filter((x) => {
                if (x.id === id) {
                  this.objectData = x;
                }
              });
              console.log('Json Object Data by ID ==> ', this.objectData);
            }
          };

How do I parse JSON with Objective-C?

  1. I recommend and use TouchJSON for parsing JSON.
  2. To answer your comment to Alex. Here's quick code that should allow you to get the fields like activity_details, last_name, etc. from the json dictionary that is returned:

    NSDictionary *userinfo=[jsondic valueforKey:@"#data"];
    NSDictionary *user;
    NSInteger i = 0;
    NSString *skey;
    if(userinfo != nil){
        for( i = 0; i < [userinfo count]; i++ ) {
            if(i)
                skey = [NSString stringWithFormat:@"%d",i];
            else
                skey = @"";
    
            user = [userinfo objectForKey:skey];
            NSLog(@"activity_details:%@",[user objectForKey:@"activity_details"]);
            NSLog(@"last_name:%@",[user objectForKey:@"last_name"]);
            NSLog(@"first_name:%@",[user objectForKey:@"first_name"]);
            NSLog(@"photo_url:%@",[user objectForKey:@"photo_url"]);
        }
    }
    

Read JSON data in a shell script

Here is a crude way to do it: Transform JSON into bash variables to eval them.

This only works for:

  • JSON which does not contain nested arrays, and
  • JSON from trustworthy sources (else it may confuse your shell script, perhaps it may even be able to harm your system, You have been warned)

Well, yes, it uses PERL to do this job, thanks to CPAN, but is small enough for inclusion directly into a script and hence is quick and easy to debug:

json2bash() {
perl -MJSON -0777 -n -E 'sub J {
my ($p,$v) = @_; my $r = ref $v;
if ($r eq "HASH") { J("${p}_$_", $v->{$_}) for keys %$v; }
elsif ($r eq "ARRAY") { $n = 0; J("$p"."[".$n++."]", $_) foreach @$v; }
else { $v =~ '"s/'/'\\\\''/g"'; $p =~ s/^([^[]*)\[([0-9]*)\](.+)$/$1$3\[$2\]/;
$p =~ tr/-/_/; $p =~ tr/A-Za-z0-9_[]//cd; say "$p='\''$v'\'';"; }
}; J("json", decode_json($_));'
}

use it like eval "$(json2bash <<<'{"a":["b","c"]}')"

Not heavily tested, though. Updates, warnings and more examples see my GIST.

Update

(Unfortunately, following is a link-only-solution, as the C code is far too long to duplicate here.)

For all those, who do not like the above solution, there now is a C program json2sh which (hopefully safely) converts JSON into shell variables. In contrast to the perl snippet, it is able to process any JSON, as long as it is well formed.

Caveats:

  • json2sh was not tested much.
  • json2sh may create variables, which start with the shellshock pattern () {

I wrote json2sh to be able to post-process .bson with Shell:

bson2json()
{
printf '[';
{ bsondump "$1"; echo "\"END$?\""; } | sed '/^{/s/$/,/';
echo ']';
};

bsons2json()
{
printf '{';
c='';
for a;
do
  printf '%s"%q":' "$c" "$a";
  c=',';
  bson2json "$a";
done;
echo '}';
};

bsons2json */*.bson | json2sh | ..

Explained:

  • bson2json dumps a .bson file such, that the records become a JSON array
    • If everything works OK, an END0-Marker is applied, else you will see something like END1.
    • The END-Marker is needed, else empty .bson files would not show up.
  • bsons2json dumps a bunch of .bson files as an object, where the output of bson2json is indexed by the filename.

This then is postprocessed by json2sh, such that you can use grep/source/eval/etc. what you need, to bring the values into the shell.

This way you can quickly process the contents of a MongoDB dump on shell level, without need to import it into MongoDB first.

How to use NSJSONSerialization

The following code fetches a JSON object from a webserver, and parses it to an NSDictionary. I have used the openweathermap API that returns a simple JSON response for this example. For keeping it simple, this code uses synchronous requests.

   NSString *urlString   = @"http://api.openweathermap.org/data/2.5/weather?q=London,uk"; // The Openweathermap JSON responder
   NSURL *url            = [[NSURL alloc]initWithString:urlString];
   NSURLRequest *request = [NSURLRequest requestWithURL:url];
   NSURLResponse *response;
   NSData *GETReply      = [NSURLConnection sendSynchronousRequest:request returningResponse:&response error:nil];
   NSDictionary *res     = [NSJSONSerialization JSONObjectWithData:GETReply options:NSJSONReadingMutableLeaves|| NSJSONReadingMutableContainers error:nil];
   Nslog(@"%@",res);

MVC: How to Return a String as JSON

The issue, I believe, is that the Json action result is intended to take an object (your model) and create an HTTP response with content as the JSON-formatted data from your model object.

What you are passing to the controller's Json method, though, is a JSON-formatted string object, so it is "serializing" the string object to JSON, which is why the content of the HTTP response is surrounded by double-quotes (I'm assuming that is the problem).

I think you can look into using the Content action result as an alternative to the Json action result, since you essentially already have the raw content for the HTTP response available.

return this.Content(returntext, "application/json");
// not sure off-hand if you should also specify "charset=utf-8" here, 
//  or if that is done automatically

Another alternative would be to deserialize the JSON result from the service into an object and then pass that object to the controller's Json method, but the disadvantage there is that you would be de-serializing and then re-serializing the data, which may be unnecessary for your purposes.

How to check for a JSON response using RSpec?

You could parse the response body like this:

parsed_body = JSON.parse(response.body)

Then you can make your assertions against that parsed content.

parsed_body["foo"].should == "bar"

Simple jQuery, PHP and JSONP example?

Use this ..

    $str = rawurldecode($_SERVER['REQUEST_URI']);
    $arr = explode("{",$str);
    $arr1 = explode("}", $arr[1]);
    $jsS = '{'.$arr1[0].'}';
    $data = json_decode($jsS,true);

Now ..

use $data['elemname'] to access the values.

send jsonp request with JSON Object.

Request format :

$.ajax({
    method : 'POST',
    url : 'xxx.com',
    data : JSONDataObj, //Use JSON.stringfy before sending data
    dataType: 'jsonp',
    contentType: 'application/json; charset=utf-8',
    success : function(response){
      console.log(response);
    }
}) 

Accessing all items in the JToken

In addition to the accepted answer I would like to give an answer that shows how to iterate directly over the Newtonsoft collections. It uses less code and I'm guessing its more efficient as it doesn't involve converting the collections.

using Newtonsoft.Json;
using Newtonsoft.Json.Linq;
//Parse the data
JObject my_obj = JsonConvert.DeserializeObject<JObject>(your_json);

foreach (KeyValuePair<string, JToken> sub_obj in (JObject)my_obj["ADDRESS_MAP"])
{
    Console.WriteLine(sub_obj.Key);
}

I started doing this myself because JsonConvert automatically deserializes nested objects as JToken (which are JObject, JValue, or JArray underneath I think).

I think the parsing works according to the following principles:

  • Every object is abstracted as a JToken

  • Cast to JObject where you expect a Dictionary

  • Cast to JValue if the JToken represents a terminal node and is a value

  • Cast to JArray if its an array

  • JValue.Value gives you the .NET type you need

Using curl POST with variables defined in bash script functions

Existing answers point out that curl can post data from a file, and employ heredocs to avoid excessive quote escaping and clearly break the JSON out onto new lines. However there is no need to define a function or capture output from cat, because curl can post data from standard input. I find this form very readable:

curl -X POST -H 'Content-Type:application/json' --data '$@-' ${API_URL} << EOF
{
  "account": {
    "email": "$email",
    "screenName": "$screenName",
    "type": "$theType",
    "passwordSettings": {
      "password": "$password",
      "passwordConfirm": "$password"
    }
  },
  "firstName": "$firstName",
  "lastName": "$lastName",
  "middleName": "$middleName",
  "locale": "$locale",
  "registrationSiteId": "$registrationSiteId",
  "receiveEmail": "$receiveEmail",
  "dateOfBirth": "$dob",
  "mobileNumber": "$mobileNumber",
  "gender": "$gender",
  "fuelActivationDate": "$fuelActivationDate",
  "postalCode": "$postalCode",
  "country": "$country",
  "city": "$city",
  "state": "$state",
  "bio": "$bio",
  "jpFirstNameKana": "$jpFirstNameKana",
  "jpLastNameKana": "$jpLastNameKana",
  "height": "$height",
  "weight": "$weight",
  "distanceUnit": "MILES",
  "weightUnit": "POUNDS",
  "heightUnit": "FT/INCHES"
}
EOF

store return json value in input hidden field

You can use input.value = JSON.stringify(obj) to transform the object to a string.
And when you need it back you can use obj = JSON.parse(input.value)

The JSON object is available on modern browsers or you can use the json2.js library from json.org

ASP.NET MVC JsonResult Date Format

0

In your cshtml,

<tr ng-repeat="value in Results">                
 <td>{{value.FileReceivedOn | mydate | date : 'dd-MM-yyyy'}} </td>
</tr>

In Your JS File, maybe app.js,

Outside of app.controller, add the below filter.

Here the "mydate" is the function which you are calling for parsing the date. Here the "app" is the variable which contains the angular.module

app.filter("mydate", function () {
    var re = /\/Date\(([0-9]*)\)\//;
    return function (x) {
        var m = x.match(re);
        if (m) return new Date(parseInt(m[1]));
        else return null;
    };
});

GUI-based or Web-based JSON editor that works like property explorer

Update: In an effort to answer my own question, here is what I've been able to uncover so far. If anyone else out there has something, I'd still be interested to find out more.

Based on JSON Schema

Commercial (No endorsement intended or implied, may or may not meet requirement)

jQuery

YAML

See Also

JSON ValueError: Expecting property name: line 1 column 2 (char 1)

  1. replace all single quotes with double quotes
  2. replace 'u"' from your strings to '"' ... so basically convert internal unicodes to strings before loading the string into json
>> strs = "{u'key':u'val'}"
>> strs = strs.replace("'",'"')
>> json.loads(strs.replace('u"','"'))

Nested JSON: How to add (push) new items to an object?

push is an Array method, for json object you may need to define it

this should do it:

library[title] = {"foregrounds" : foregrounds,"backgrounds" : backgrounds};

'JSON' is undefined error in JavaScript in Internet Explorer

Check for extra commas in your JSON response. If the last element of an array has a comma, this will break in IE

In Rails, how do you render JSON using a view?

This is potentially a better option and faster than ERB: https://github.com/dewski/json_builder

Angular 2: Get Values of Multiple Checked Checkboxes

I have find a solution thanks to Gunter! Here is my whole code if it could help anyone:

<div class="form-group">
            <label for="options">Options :</label>
            <div *ngFor="#option of options; #i = index">
                <label>
                    <input type="checkbox"
                           name="options"
                           value="{{option}}"
                           [checked]="options.indexOf(option) >= 0"
                           (change)="updateCheckedOptions(option, $event)"/>
                    {{option}}
                </label>
            </div>
        </div>

Here are the 3 objects I'm using:

options = ['OptionA', 'OptionB', 'OptionC'];
optionsMap = {
        OptionA: false,
        OptionB: false,
        OptionC: false,
};
optionsChecked = [];

And there are 3 useful methods:

1. To initiate optionsMap:

initOptionsMap() {
    for (var x = 0; x<this.order.options.length; x++) {
        this.optionsMap[this.options[x]] = true;
    }
}

2. to update the optionsMap:

updateCheckedOptions(option, event) {
   this.optionsMap[option] = event.target.checked;
}

3. to convert optionsMap into optionsChecked and store it in options before sending the POST request:

updateOptions() {
    for(var x in this.optionsMap) {
        if(this.optionsMap[x]) {
            this.optionsChecked.push(x);
        }
    }
    this.options = this.optionsChecked;
    this.optionsChecked = [];
}

What is the convention in JSON for empty vs. null?

There is the question whether we want to differentiate between cases:

  1. "phone" : "" = the value is empty

  2. "phone" : null = the value for "phone" was not set yet

If we want differentiate I would use null for this. Otherwise we would need to add a new field like "isAssigned" or so. This is an old Database issue.

How can I get the key value in a JSON object?

You may need:

Object.keys(JSON[0]);

To get something like:

[ 'amount', 'job', 'month', 'year' ]

Note: Your JSON is invalid.

Can I get JSON to load into an OrderedDict?

Simple version for Python 2.7+

my_ordered_dict = json.loads(json_str, object_pairs_hook=collections.OrderedDict)

Or for Python 2.4 to 2.6

import simplejson as json
import ordereddict

my_ordered_dict = json.loads(json_str, object_pairs_hook=ordereddict.OrderedDict)

NumPy array is not JSON serializable

Store as JSON a numpy.ndarray or any nested-list composition.

class NumpyEncoder(json.JSONEncoder):
    def default(self, obj):
        if isinstance(obj, np.ndarray):
            return obj.tolist()
        return json.JSONEncoder.default(self, obj)

a = np.array([[1, 2, 3], [4, 5, 6]])
print(a.shape)
json_dump = json.dumps({'a': a, 'aa': [2, (2, 3, 4), a], 'bb': [2]}, cls=NumpyEncoder)
print(json_dump)

Will output:

(2, 3)
{"a": [[1, 2, 3], [4, 5, 6]], "aa": [2, [2, 3, 4], [[1, 2, 3], [4, 5, 6]]], "bb": [2]}

To restore from JSON:

json_load = json.loads(json_dump)
a_restored = np.asarray(json_load["a"])
print(a_restored)
print(a_restored.shape)

Will output:

[[1 2 3]
 [4 5 6]]
(2, 3)

Parsing HTTP Response in Python

TL&DR: When you typically get data from a server, it is sent in bytes. The rationale is that these bytes will need to be 'decoded' by the recipient, who should know how to use the data. You should decode the binary upon arrival to not get 'b' (bytes) but instead a string.

Use case:

import requests    
def get_data_from_url(url):
        response = requests.get(url_to_visit)
        response_data_split_by_line = response.content.decode('utf-8').splitlines()
        return response_data_split_by_line

In this example, I decode the content that I received into UTF-8. For my purposes, I then split it by line, so I can loop through each line with a for loop.

Loop and get key/value pair for JSON array using jQuery

var obj = $.parseJSON(result);
for (var prop in obj) {
    alert(prop + " is " + obj[prop]);
}

Convert js Array() to JSon object for use with JQuery .ajax

You can iterate the key/value pairs of the saveData object to build an array of the pairs, then use join("&") on the resulting array:

var a = [];
for (key in saveData) {
    a.push(key+"="+saveData[key]);
}
var serialized = a.join("&") // a=2&c=1

Use NSInteger as array index

According to the error message, you declared myLoc as a pointer to an NSInteger (NSInteger *myLoc) rather than an actual NSInteger (NSInteger myLoc). It needs to be the latter.

Convert json data to a html table

I have rewritten your code in vanilla-js, using DOM methods to prevent html injection.

Demo

_x000D_
_x000D_
var _table_ = document.createElement('table'),_x000D_
  _tr_ = document.createElement('tr'),_x000D_
  _th_ = document.createElement('th'),_x000D_
  _td_ = document.createElement('td');_x000D_
_x000D_
// Builds the HTML Table out of myList json data from Ivy restful service._x000D_
function buildHtmlTable(arr) {_x000D_
  var table = _table_.cloneNode(false),_x000D_
    columns = addAllColumnHeaders(arr, table);_x000D_
  for (var i = 0, maxi = arr.length; i < maxi; ++i) {_x000D_
    var tr = _tr_.cloneNode(false);_x000D_
    for (var j = 0, maxj = columns.length; j < maxj; ++j) {_x000D_
      var td = _td_.cloneNode(false);_x000D_
      cellValue = arr[i][columns[j]];_x000D_
      td.appendChild(document.createTextNode(arr[i][columns[j]] || ''));_x000D_
      tr.appendChild(td);_x000D_
    }_x000D_
    table.appendChild(tr);_x000D_
  }_x000D_
  return table;_x000D_
}_x000D_
_x000D_
// Adds a header row to the table and returns the set of columns._x000D_
// Need to do union of keys from all records as some records may not contain_x000D_
// all records_x000D_
function addAllColumnHeaders(arr, table) {_x000D_
  var columnSet = [],_x000D_
    tr = _tr_.cloneNode(false);_x000D_
  for (var i = 0, l = arr.length; i < l; i++) {_x000D_
    for (var key in arr[i]) {_x000D_
      if (arr[i].hasOwnProperty(key) && columnSet.indexOf(key) === -1) {_x000D_
        columnSet.push(key);_x000D_
        var th = _th_.cloneNode(false);_x000D_
        th.appendChild(document.createTextNode(key));_x000D_
        tr.appendChild(th);_x000D_
      }_x000D_
    }_x000D_
  }_x000D_
  table.appendChild(tr);_x000D_
  return columnSet;_x000D_
}_x000D_
_x000D_
document.body.appendChild(buildHtmlTable([{_x000D_
    "name": "abc",_x000D_
    "age": 50_x000D_
  },_x000D_
  {_x000D_
    "age": "25",_x000D_
    "hobby": "swimming"_x000D_
  },_x000D_
  {_x000D_
    "name": "xyz",_x000D_
    "hobby": "programming"_x000D_
  }_x000D_
]));
_x000D_
_x000D_
_x000D_

Reading JSON POST using PHP

You have empty $_POST. If your web-server wants see data in json-format you need to read the raw input and then parse it with JSON decode.

You need something like that:

$json = file_get_contents('php://input');
$obj = json_decode($json);

Also you have wrong code for testing JSON-communication...

CURLOPT_POSTFIELDS tells curl to encode your parameters as application/x-www-form-urlencoded. You need JSON-string here.

UPDATE

Your php code for test page should be like that:

$data_string = json_encode($data);

$ch = curl_init('http://webservice.local/');
curl_setopt($ch, CURLOPT_CUSTOMREQUEST, "POST");
curl_setopt($ch, CURLOPT_POSTFIELDS, $data_string);
curl_setopt($ch, CURLOPT_RETURNTRANSFER, true);
curl_setopt($ch, CURLOPT_HTTPHEADER, array(
        'Content-Type: application/json',
        'Content-Length: ' . strlen($data_string))
);

$result = curl_exec($ch);
$result = json_decode($result);
var_dump($result);

Also on your web-service page you should remove one of the lines header('Content-type: application/json');. It must be called only once.

node.js TypeError: path must be absolute or specify root to res.sendFile [failed to parse JSON]

The error is pretty clear, you need to specify an absolute (instead of relative) path and/or set root in the config object for res.sendFile(). Examples:

// assuming index.html is in the same directory as this script

res.sendFile(__dirname + '/index.html');

or specify a root (which is used as the base path for the first argument to res.sendFile():

res.sendFile('index.html', { root: __dirname });

Specifying the root path is more useful when you're passing a user-generated file path which could potentially contain malformed/malicious parts like .. (e.g. ../../../../../../etc/passwd). Setting the root path prevents such malicious paths from being used to access files outside of that base path.

Convert InputStream to JSONObject

you could use an Entity:

FileEntity entity = new FileEntity(jsonFile, "application/json");
String jsonString = EntityUtils.toString(entity)

Uncaught TypeError: Cannot read property 'ownerDocument' of undefined

If you use ES6 anon functions, it will conflict with $(this)

This works:

$('.dna-list').on('click', '.card', function(e) {
  console.log($(this));
});

This doesn't work:

$('.dna-list').on('click', '.card', (e) => {
  console.log($(this));
});

JSON Post with Customized HTTPHeader Field

I tried as you mentioned, but only first parameter is going through and rest all are appearing in the server as undefined. I am passing JSONWebToken as part of header.

.ajax({
    url: 'api/outletadd',
    type: 'post',
    data: { outletname:outletname , addressA:addressA , addressB:addressB, city:city , postcode:postcode , state:state , country:country , menuid:menuid },
    headers: {
        authorization: storedJWT
    },
    dataType: 'json',
    success: function (data){
        alert("Outlet Created");
    },
    error: function (data){
        alert("Outlet Creation Failed, please try again.");        
    }

    });

MVC ajax json post to controller action method

Below is how I got this working.

The Key point was: I needed to use the ViewModel associated with the view in order for the runtime to be able to resolve the object in the request.

[I know that that there is a way to bind an object other than the default ViewModel object but ended up simply populating the necessary properties for my needs as I could not get it to work]

[HttpPost]  
  public ActionResult GetDataForInvoiceNumber(MyViewModel myViewModel)  
  {            
     var invoiceNumberQueryResult = _viewModelBuilder.HydrateMyViewModelGivenInvoiceDetail(myViewModel.InvoiceNumber, myViewModel.SelectedCompanyCode);
     return Json(invoiceNumberQueryResult, JsonRequestBehavior.DenyGet);
  }

The JQuery script used to call this action method:

var requestData = {
         InvoiceNumber: $.trim(this.value),
         SelectedCompanyCode: $.trim($('#SelectedCompanyCode').val())
      };


      $.ajax({
         url: '/en/myController/GetDataForInvoiceNumber',
         type: 'POST',
         data: JSON.stringify(requestData),
         dataType: 'json',
         contentType: 'application/json; charset=utf-8',
         error: function (xhr) {
            alert('Error: ' + xhr.statusText);
         },
         success: function (result) {
            CheckIfInvoiceFound(result);
         },
         async: true,
         processData: false
      });

Iterating over JSON object in C#

This worked for me, converts to nested JSON to easy to read YAML

    string JSONDeserialized {get; set;}
    public int indentLevel;

    private bool JSONDictionarytoYAML(Dictionary<string, object> dict)
    {
        bool bSuccess = false;
        indentLevel++;

        foreach (string strKey in dict.Keys)
        {
            string strOutput = "".PadLeft(indentLevel * 3) + strKey + ":";
            JSONDeserialized+="\r\n" + strOutput;

            object o = dict[strKey];
            if (o is Dictionary<string, object>)
            {
                JSONDictionarytoYAML((Dictionary<string, object>)o);
            }
            else if (o is ArrayList)
            {
                foreach (object oChild in ((ArrayList)o))
                {
                    if (oChild is string)
                    {
                        strOutput = ((string)oChild);
                        JSONDeserialized += strOutput + ",";
                    }
                    else if (oChild is Dictionary<string, object>)
                    {
                        JSONDictionarytoYAML((Dictionary<string, object>)oChild);
                        JSONDeserialized += "\r\n";  
                    }
                }
            }
            else
            {
                strOutput = o.ToString();
                JSONDeserialized += strOutput;
            }
        }

        indentLevel--;

        return bSuccess;

    }

usage

        Dictionary<string, object> JSONDic = new Dictionary<string, object>();
        JavaScriptSerializer js = new JavaScriptSerializer();

          try {

            JSONDic = js.Deserialize<Dictionary<string, object>>(inString);
            JSONDeserialized = "";

            indentLevel = 0;
            DisplayDictionary(JSONDic); 

            return JSONDeserialized;

        }
        catch (Exception)
        {
            return "Could not parse input JSON string";
        }

How to iterate over a JSONObject?

Can't believe that there is no more simple and secured solution than using an iterator in this answers...

JSONObject names () method returns a JSONArray of the JSONObject keys, so you can simply walk though it in loop:

JSONObject object = new JSONObject ();
JSONArray keys = object.names ();

for (int i = 0; i < keys.length (); i++) {
   
   String key = keys.getString (i); // Here's your key
   String value = object.getString (key); // Here's your value
   
}

Remove a JSON attribute

Simple:

delete myObj.test.key1;

How to auto-generate a C# class file from a JSON string

Visual Studio 2012 (with ASP.NET and Web Tools 2012.2 RC installed) supports this natively.

Visual Studio 2013 onwards have this built-in.

Visual Studio Paste JSON as Classes screenshot (Image courtesy: robert.muehsig)

jQuery getJSON save result into variable

$.getJSon expects a callback functions either you pass it to the callback function or in callback function assign it to global variale.

var globalJsonVar;

    $.getJSON("http://127.0.0.1:8080/horizon-update", function(json){
               //do some thing with json  or assign global variable to incoming json. 
                globalJsonVar=json;
          });

IMO best is to call the callback function. which is nicer to eyes, readability aspects.

$.getJSON("http://127.0.0.1:8080/horizon-update", callbackFuncWithData);

function callbackFuncWithData(data)
{
 // do some thing with data 
}

Facebook Graph API, how to get users email?

The only way to get the users e-mail address is to request extended permissions on the email field. The user must allow you to see this and you cannot get the e-mail addresses of the user's friends.

http://developers.facebook.com/docs/authentication/permissions

You can do this if you are using Facebook connect by passing scope=email in the get string of your call to the Auth Dialog.

I'd recommend using an SDK instead of file_get_contents as it makes it far easier to perform the Oauth authentication.

Access elements in json object like an array

I found a straight forward way of solving this, with the use of JSON.parse.

Let's assume the json below is inside the variable jsontext.

[
  ["Blankaholm", "Gamleby"],
  ["2012-10-23", "2012-10-22"],
  ["Blankaholm. Under natten har det varit inbrott", "E22 i med Gamleby. Singelolycka. En bilist har.],
  ["57.586174","16.521841"], ["57.893162","16.406090"]
]

The solution is this:

var parsedData = JSON.parse(jsontext);

Now I can access the elements the following way:

var cities = parsedData[0];

json.dumps vs flask.jsonify

consider

data={'fld':'hello'}

now

jsonify(data)

will yield {'fld':'hello'} and

json.dumps(data)

gives

"<html><body><p>{'fld':'hello'}</p></body></html>"

Converting a string to JSON object

convert the string to HashMap using Object Mapper ...

new ObjectMapper().readValue(string, Map.class);

Internally Map will behave as JSON Object

I want to add a JSONObject to a JSONArray and that JSONArray included in other JSONObject

JSONArray jsonArray = new JSONArray();

for (loop) {
    JSONObject jsonObj= new JSONObject();
    jsonObj.put("srcOfPhoto", srcOfPhoto);
    jsonObj.put("username", "name"+count);
    jsonObj.put("userid", "userid"+count);

    jsonArray.put(jsonObj.valueToString());
}

JSONObject parameters = new JSONObject();

parameters.put("action", "remove");

parameters.put("datatable", jsonArray );

parameters.put(Constant.MSG_TYPE , Constant.SUCCESS);

Why were you using an Hashmap if what you wanted was to put it into a JSONObject?

EDIT: As per http://www.json.org/javadoc/org/json/JSONArray.html

EDIT2: On the JSONObject method used, I'm following the code available at: https://github.com/stleary/JSON-java/blob/master/JSONObject.java#L2327 , that method is not deprecated.

We're storing a string representation of the JSONObject, not the JSONObject itself

How to get JSON objects value if its name contains dots?

What you want is:

var smth = mydata.list[0]["points.bean.pointsBase"][0].time;

In JavaScript, any field you can access using the . operator, you can access using [] with a string version of the field name.

How can I tell jackson to ignore a property for which I don't have control over the source code?

You can use Jackson Mixins. For example:

class YourClass {
  public int ignoreThis() { return 0; }    
}

With this Mixin

abstract class MixIn {
  @JsonIgnore abstract int ignoreThis(); // we don't need it!  
}

With this:

objectMapper.getSerializationConfig().addMixInAnnotations(YourClass.class, MixIn.class);

Edit:

Thanks to the comments, with Jackson 2.5+, the API has changed and should be called with objectMapper.addMixIn(Class<?> target, Class<?> mixinSource)

Android- create JSON Array and JSON Object

            Map<String, String> params = new HashMap<String, String>();

            //** Temp array
            List<String[]> tmpArray = new ArrayList<>();
            tmpArray.add(new String[]{"b001","book1"}); 
            tmpArray.add(new String[]{"b002","book2"}); 

            //** Json Array Example
            JSONArray jrrM = new JSONArray();
            for(int i=0; i<tmpArray.size(); i++){
                JSONArray jrr = new JSONArray();
                jrr.put(tmpArray.get(i)[0]);
                jrr.put(tmpArray.get(i)[1]);
                jrrM.put(jrr);
            }

           //Json Object Example
           JSONObject jsonObj = new JSONObject();
            try {
                jsonObj.put("plno","000000001");                   
                jsonObj.put("rows", jrrM);

            }catch (JSONException ex){
                ex.printStackTrace();
            }   


            // Bundles them
            params.put("user", "guest");
            params.put("tb", "book_store");
            params.put("action","save");
            params.put("data", jsonObj.toString());

           // Now you can send them to the server.

Remove Backslashes from Json Data in JavaScript

You need to deserialize the JSON once before returning it as response. Please refer below code. This works for me:

JavaScriptSerializer jss = new JavaScriptSerializer();
Object finalData = jss.DeserializeObject(str);

How to modify values of JsonObject / JsonArray directly?

Another approach would be to deserialize into a java.util.Map, and then just modify the Java Map as wanted. This separates the Java-side data handling from the data transport mechanism (JSON), which is how I prefer to organize my code: using JSON for data transport, not as a replacement data structure.

Spring RequestMapping for controllers that produce and consume JSON

You shouldn't need to configure the consumes or produces attribute at all. Spring will automatically serve JSON based on the following factors.

  • The accepts header of the request is application/json
  • @ResponseBody annotated method
  • Jackson library on classpath

You should also follow Wim's suggestion and define your controller with the @RestController annotation. This will save you from annotating each request method with @ResponseBody

Another benefit of this approach would be if a client wants XML instead of JSON, they would get it. They would just need to specify xml in the accepts header.

How to convert a list of numbers to jsonarray in Python

import json
row = [1L,[0.1,0.2],[[1234L,1],[134L,2]]]
row_json = json.dumps(row)

How to return a complex JSON response with Node.js?

I don't know if this is really any different, but rather than iterate over the query cursor, you could do something like this:

query.exec(function (err, results){
  if (err) res.writeHead(500, err.message)
  else if (!results.length) res.writeHead(404);
  else {
    res.writeHead(200, { 'Content-Type': 'application/json' });
    res.write(JSON.stringify(results.map(function (msg){ return {msgId: msg.fileName}; })));
  }
  res.end();
});

How to return JSON data from spring Controller using @ResponseBody

Add the below dependency to your pom.xml:

<dependency>
    <groupId>com.fasterxml.jackson.core</groupId>
    <artifactId>jackson-databind</artifactId>
    <version>2.5.0</version>
</dependency>

Pretty-Printing JSON with PHP

Simple way for php>5.4: like in Facebook graph

$Data = array('a' => 'apple', 'b' => 'banana', 'c' => 'catnip');
$json= json_encode($Data, JSON_PRETTY_PRINT);
header('Content-Type: application/json');
print_r($json);

Result in browser

{
    "a": "apple",
    "b": "banana",
    "c": "catnip"
}

is not JSON serializable

It's worth noting that the QuerySet.values_list() method doesn't actually return a list, but an object of type django.db.models.query.ValuesListQuerySet, in order to maintain Django's goal of lazy evaluation, i.e. the DB query required to generate the 'list' isn't actually performed until the object is evaluated.

Somewhat irritatingly, though, this object has a custom __repr__ method which makes it look like a list when printed out, so it's not always obvious that the object isn't really a list.

The exception in the question is caused by the fact that custom objects cannot be serialized in JSON, so you'll have to convert it to a list first, with...

my_list = list(self.get_queryset().values_list('code', flat=True))

...then you can convert it to JSON with...

json_data = json.dumps(my_list)

You'll also have to place the resulting JSON data in an HttpResponse object, which, apparently, should have a Content-Type of application/json, with...

response = HttpResponse(json_data, content_type='application/json')

...which you can then return from your function.

Can JavaScript connect with MySQL?

Client-side JavaScript cannot access MySQL without some kind of bridge. But the above bold statements that JavaScript is just a client-side language are incorrect -- JavaScript can run client-side and server-side, as with Node.js.

Node.js can access MySQL through something like https://github.com/sidorares/node-mysql2

You might also develop something using Socket.IO

Did you mean to ask whether a client-side JS app can access MySQL? I am not sure if such libraries exist, but they are possible.

EDIT: Since writing, we now have MySQL Cluster:

The MySQL Cluster JavaScript Driver for Node.js is just what it sounds like it is – it’s a connector that can be called directly from your JavaScript code to read and write your data. As it accesses the data nodes directly, there is no extra latency from passing through a MySQL Server and need to convert from JavaScript code//objects into SQL operations. If for some reason, you’d prefer it to pass through a MySQL Server (for example if you’re storing tables in InnoDB) then that can be configured.

Returning JSON response from Servlet to Javascript/JSP page

Got it working! I should have been building a JSONArray of JSONObjects and then add the array to a final "Addresses" JSONObject. Observe the following:

JSONObject json      = new JSONObject();
JSONArray  addresses = new JSONArray();
JSONObject address;
try
{
   int count = 15;

   for (int i=0 ; i<count ; i++)
   {
       address = new JSONObject();
       address.put("CustomerName"     , "Decepticons" + i);
       address.put("AccountId"        , "1999" + i);
       address.put("SiteId"           , "1888" + i);
       address.put("Number"            , "7" + i);
       address.put("Building"          , "StarScream Skyscraper" + i);
       address.put("Street"            , "Devestator Avenue" + i);
       address.put("City"              , "Megatron City" + i);
       address.put("ZipCode"          , "ZZ00 XX1" + i);
       address.put("Country"           , "CyberTron" + i);
       addresses.add(address);
   }
   json.put("Addresses", addresses);
}
catch (JSONException jse)
{ 

}
response.setContentType("application/json");
response.getWriter().write(json.toString());

This worked and returned valid and parse-able JSON. Hopefully this helps someone else in the future. Thanks for your help Marcel

Convert array to JSON string in swift

For Swift 3.0 you have to use this:

var postString = ""
    do {
        let data =  try JSONSerialization.data(withJSONObject: self.arrayNParcel, options: .prettyPrinted)
        let string1:String = NSString(data: data, encoding: String.Encoding.utf8.rawValue) as! String

        postString = "arrayData=\(string1)&user_id=\(userId)&markupSrcReport=\(markup)"
    } catch {
        print(error.localizedDescription)
    }
    request.httpBody = postString.data(using: .utf8)

100% working TESTED

How do I POST JSON data with cURL?

For Windows, having a single quote for the -d value did not work for me, but it did work after changing to double quote. Also I needed to escape double quotes inside curly brackets.

That is, the following did not work:

curl -i -X POST -H "Content-Type: application/json" -d '{"key":"val"}' http://localhost:8080/appname/path

But the following worked:

curl -i -X POST -H "Content-Type: application/json" -d "{\"key\":\"val\"}" http://localhost:8080/appname/path

Use C# HttpWebRequest to send json to web service

First of all you missed ScriptService attribute to add in webservice.

[ScriptService]

After then try following method to call webservice via JSON.

        var webAddr = "http://Domain/VBRService.asmx/callJson";
        var httpWebRequest = (HttpWebRequest)WebRequest.Create(webAddr);
        httpWebRequest.ContentType = "application/json; charset=utf-8";
        httpWebRequest.Method = "POST";            

        using (var streamWriter = new StreamWriter(httpWebRequest.GetRequestStream()))
        {
            string json = "{\"x\":\"true\"}";

            streamWriter.Write(json);
            streamWriter.Flush();
        }

        var httpResponse = (HttpWebResponse)httpWebRequest.GetResponse();
        using (var streamReader = new StreamReader(httpResponse.GetResponseStream()))
        {
            var result = streamReader.ReadToEnd();
            return result;
        }

Using GSON to parse a JSON array

Gson gson = new Gson();
Wrapper[] arr = gson.fromJson(str, Wrapper[].class);

class Wrapper{
    int number;
    String title;       
}

Seems to work fine. But there is an extra , Comma in your string.

[
    { 
        "number" : "3",
        "title" : "hello_world"
    },
    { 
        "number" : "2",
        "title" : "hello_world"
    }
]

PHP returning JSON to JQUERY AJAX CALL

You can return json in PHP this way:

header('Content-Type: application/json');
echo json_encode(array('foo' => 'bar'));
exit;

Convert a object into JSON in REST service by Spring MVC

You can always add the @Produces("application/json") above your web method or specify produces="application/json" to return json. Then on top of the Student class you can add @XmlRootElement from javax.xml.bind.annotation package.

Please note, it might not be a good idea to directly return model classes. Just a suggestion.

HTH.

Load local JSON file into variable

My solution, as answered here, is to use:

    var json = require('./data.json'); //with path

The file is loaded only once, further requests use cache.

edit To avoid caching, here's the helper function from this blogpost given in the comments, using the fs module:

var readJson = (path, cb) => {
  fs.readFile(require.resolve(path), (err, data) => {
    if (err)
      cb(err)
    else
      cb(null, JSON.parse(data))
  })
}

Parse JSON String into List<string>

Try this:

using System;
using Newtonsoft.Json;
using System.Collections.Generic;
public class Program
{
    public static void Main()
    {
        List<Man> Men = new List<Man>();

        Man m1 = new Man();
        m1.Number = "+1-9169168158";
        m1.Message = "Hello Bob from 1";
        m1.UniqueCode = "0123";
        m1.State = 0;

        Man m2 = new Man();
        m2.Number = "+1-9296146182";
        m2.Message = "Hello Bob from 2";
        m2.UniqueCode = "0125";
        m2.State = 0;

        Men.AddRange(new Man[] { m1, m2 });

        string result = JsonConvert.SerializeObject(Men);
        Console.WriteLine(result);  

        List<Man> NewMen = JsonConvert.DeserializeObject<List<Man>>(result);
        foreach(Man m in NewMen) Console.WriteLine(m.Message);
    }
}
public class Man
{
    public string Number{get;set;}
    public string Message {get;set;}
    public string UniqueCode {get;set;}
    public int State {get;set;}
}

Composer could not find a composer.json

You could try updating the composer:

sudo composer self-update

If that doest works remove composer files & then use: SSH into terminal & type :

$ cd ~
$ sudo curl -sS https://getcomposer.org/installer | sudo php
$ sudo mv composer.phar /usr/local/bin/composer
$ sudo ln -s /usr/local/bin/composer /usr/bin/composer

If you face an error that says: PHP Fatal error: Uncaught exception 'ErrorException' with message 'proc_open(): fork failed - Cannot allocate memory' in phar

/bin/dd if=/dev/zero of=/var/swap.1 bs=1M count=1024
/sbin/mkswap /var/swap.1
/sbin/swapon /var/swap.1

To install package use:

composer global require "package-name"

What is the difference between json.dumps and json.load?

json loads -> returns an object from a string representing a json object.

json dumps -> returns a string representing a json object from an object.

load and dump -> read/write from/to file instead of string

Pass multiple parameters to rest API - Spring

you can pass multiple params in url like

http://localhost:2000/custom?brand=dell&limit=20&price=20000&sort=asc

and in order to get this query fields , you can use map like

    @RequestMapping(method = RequestMethod.GET, value = "/custom")
    public String controllerMethod(@RequestParam Map<String, String> customQuery) {

        System.out.println("customQuery = brand " + customQuery.containsKey("brand"));
        System.out.println("customQuery = limit " + customQuery.containsKey("limit"));
        System.out.println("customQuery = price " + customQuery.containsKey("price"));
        System.out.println("customQuery = other " + customQuery.containsKey("other"));
        System.out.println("customQuery = sort " + customQuery.containsKey("sort"));

        return customQuery.toString();
    }

Fastest method of screen capturing on Windows

I realize the following suggestion doesn't answer your question, but the simplest method I have found to capture a rapidly-changing DirectX view, is to plug a video camera into the S-video port of the video card, and record the images as a movie. Then transfer the video from the camera back to an MPG, WMV, AVI etc. file on the computer.

IntelliJ IDEA shows errors when using Spring's @Autowired annotation

The following worked for me:

  1. Find all classes implementing the service(interface) which is giving the error.
  2. Mark each of those classes with the @Service annotation, to indicate them as business logic classes.
  3. Rebuild the project.

Searching for Text within Oracle Stored Procedures

 SELECT * FROM ALL_source WHERE UPPER(text) LIKE '%BLAH%'

EDIT Adding additional info:

 SELECT * FROM DBA_source WHERE UPPER(text) LIKE '%BLAH%'

The difference is dba_source will have the text of all stored objects. All_source will have the text of all stored objects accessible by the user performing the query. Oracle Database Reference 11g Release 2 (11.2)

Another difference is that you may not have access to dba_source.

How to debug a stored procedure in Toad?

Open a PL/SQL object in the Editor.

Click on the main toolbar or select Session | Toggle Compiling with Debug. This enables debugging.

Compile the object on the database.

Select one of the following options on the Execute toolbar to begin debugging: Execute PL/SQL with debugger () Step over Step into Run to cursor

Tomcat: java.lang.IllegalArgumentException: Invalid character found in method name. HTTP method names must be tokens

I was getting the same exception, whenever a page was getting loaded,

NFO: Error parsing HTTP request header
 Note: further occurrences of HTTP header parsing errors will be logged at DEBUG level.
java.lang.IllegalArgumentException: Invalid character found in method name. HTTP method names must be tokens
    at org.apache.coyote.http11.InternalInputBuffer.parseRequestLine(InternalInputBuffer.java:139)
    at org.apache.coyote.http11.AbstractHttp11Processor.process(AbstractHttp11Processor.java:1028)
    at org.apache.coyote.AbstractProtocol$AbstractConnectionHandler.process(AbstractProtocol.java:637)
    at org.apache.tomcat.util.net.JIoEndpoint$SocketProcessor.run(JIoEndpoint.java:316)
    at java.util.concurrent.ThreadPoolExecutor.runWorker(ThreadPoolExecutor.java:1149)
    at java.util.concurrent.ThreadPoolExecutor$Worker.run(ThreadPoolExecutor.java:624)
    at org.apache.tomcat.util.threads.TaskThread$WrappingRunnable.run(TaskThread.java:61)
    at java.lang.Thread.run(Thread.java:748)

I found that one of my page URL was https instead of http, when I changed the same, error was gone.

How do I make a burn down chart in Excel?

No macros required. Data as below, two columns, dates don't need to be in order. Select range, convert to a Table (Ctrl+T). When data is added to the table, a chart based on the table will automatically include the added data.

Select table, insert a line chart. Right click chart, choose Select Data, click on Blank and Hidden Cells button, choose Interpolate option.

Burndown Chart of Pages Read

Delete a row in Excel VBA

Something like this will do it:

Rows("12:12").Select
Selection.Delete

So in your code it would look like something like this:

Rows(CStr(rand) & ":" & CStr(rand)).Select
Selection.Delete

Reading a plain text file in Java

Here's another way to do it without using external libraries:

import java.io.File;
import java.io.FileReader;
import java.io.IOException;

public String readFile(String filename)
{
    String content = null;
    File file = new File(filename); // For example, foo.txt
    FileReader reader = null;
    try {
        reader = new FileReader(file);
        char[] chars = new char[(int) file.length()];
        reader.read(chars);
        content = new String(chars);
        reader.close();
    } catch (IOException e) {
        e.printStackTrace();
    } finally {
        if(reader != null){
            reader.close();
        }
    }
    return content;
}

Get first line of a shell command's output

I would use:

awk 'FNR <= 1' file_*.txt

As @Kusalananda points out there are many ways to capture the first line in command line but using the head -n 1 may not be the best option when using wildcards since it will print additional info. Changing 'FNR == i' to 'FNR <= i' allows to obtain the first i lines.

For example, if you have n files named file_1.txt, ... file_n.txt:

awk 'FNR <= 1' file_*.txt

hello
...
bye

But with head wildcards print the name of the file:

head -1 file_*.txt

==> file_1.csv <==
hello
...
==> file_n.csv <==
bye

Difference between onLoad and ng-init in angular

Works for me.

<div ng-show="$scope.showme === true">Hello World</div>
<div ng-repeat="a in $scope.bigdata" ng-init="$scope.showme = true">{{ a.title }}</div>

Using iFrames In ASP.NET

try this

<iframe name="myIframe" id="myIframe" width="400px" height="400px" runat="server"></iframe>

Expose this iframe in the master page's codebehind:

public HtmlControl iframe
{
get
{
return this.myIframe;
}
}

Add the MasterType directive for the content page to strongly typed Master Page.

<%@ Page Language="C#" MasterPageFile="~/MasterPage.master" AutoEventWireup="true" CodeFile="Default.aspx.cs" Inherits=_Default" Title="Untitled Page" %>
<%@ MasterType VirtualPath="~/MasterPage.master" %>

In code behind

protected void Page_Load(object sender, EventArgs e)
{
this.Master.iframe.Attributes.Add("src", "some.aspx");
}

Checkbox angular material checked by default

this works for me in Angular 7

// in component.ts
checked: boolean = true;

changeValue(value) {
    this.checked = !value;
}

// in component.html
<mat-checkbox value="checked" (click)="changeValue(checked)" color="primary">
   some Label
</mat-checkbox>

I hope help someone ... greetings. let me know if someone have some easiest

How can I handle the warning of file_get_contents() function in PHP?

You can also set your error handler as an anonymous function that calls an Exception and use a try / catch on that exception.

set_error_handler(
    function ($severity, $message, $file, $line) {
        throw new ErrorException($message, $severity, $severity, $file, $line);
    }
);

try {
    file_get_contents('www.google.com');
}
catch (Exception $e) {
    echo $e->getMessage();
}

restore_error_handler();

Seems like a lot of code to catch one little error, but if you're using exceptions throughout your app, you would only need to do this once, way at the top (in an included config file, for instance), and it will convert all your errors to Exceptions throughout.

How can I add a PHP page to WordPress?

You can add any php file in under your active themes folder like (/wp-content/themes/your_active_theme/) and then you can go to add new page from wp-admin and select this page template from page template options.

<?php
/*
 Template Name: Your Template Name
 */
?>

And there is one other way like you can include your file in functions.php and create shortcode from that and then you can put that shortcode in your page like this.

// CODE in functions.php 

function abc(){
 include_once('your_file_name.php');
}
add_shortcode('abc' , 'abc');

And then you can use this shortcode in wp-admin side page like this [abc].

Rounding Bigdecimal values with 2 Decimal Places

I think that the RoundingMode you are looking for is ROUND_HALF_EVEN. From the javadoc:

Rounding mode to round towards the "nearest neighbor" unless both neighbors are equidistant, in which case, round towards the even neighbor. Behaves as for ROUND_HALF_UP if the digit to the left of the discarded fraction is odd; behaves as for ROUND_HALF_DOWN if it's even. Note that this is the rounding mode that minimizes cumulative error when applied repeatedly over a sequence of calculations.

Here is a quick test case:

BigDecimal a = new BigDecimal("10.12345");
BigDecimal b = new BigDecimal("10.12556");

a = a.setScale(2, BigDecimal.ROUND_HALF_EVEN);
b = b.setScale(2, BigDecimal.ROUND_HALF_EVEN);

System.out.println(a);
System.out.println(b);

Correctly prints:

10.12
10.13

UPDATE:

setScale(int, int) has not been recommended since Java 1.5, when enums were first introduced, and was finally deprecated in Java 9. You should now use setScale(int, RoundingMode) e.g:

setScale(2, RoundingMode.HALF_EVEN)

How to calculate difference in hours (decimal) between two dates in SQL Server?

Declare @date1 datetime
Declare @date2 datetime

Set @date1 = '11/20/2009 11:00:00 AM'
Set @date2 = '11/20/2009 12:00:00 PM'

Select Cast(DateDiff(hh, @date1, @date2) as decimal(3,2)) as HoursApart

Result = 1.00

Simulator or Emulator? What is the difference?

Simple Explanation.

If you want to convert your PC (running Windows) into Mac, you can do either of these:

(1) You can simply install a Mac theme on your Windows. So, your PC feels more like Mac, but you can't actually run any Mac programs. (SIMULATION)

(or)

(2) You can program your PC to run like Mac (I'm not sure if this is possible :P ). Now you can even run Mac programs successfully and expect the same output as on Mac. (EMULATION)

In the first case, you can experience Mac, but you can't expect the same output as on Mac.
In the second case, you can expect the same output as on Mac, but still the fact remains that it is only a PC.

Multiple separate IF conditions in SQL Server

To avoid syntax errors, be sure to always put BEGIN and END after an IF clause, eg:

IF (@A!= @SA)
   BEGIN
   --do stuff
   END
IF (@C!= @SC)
   BEGIN
   --do stuff
   END

... and so on. This should work as expected. Imagine BEGIN and END keyword as the opening and closing bracket, respectively.

Need to remove href values when printing in Chrome

Bootstrap does the same thing (... as the selected answer below).

@media print {
  a[href]:after {
    content: " (" attr(href) ")";
  }
}

Just remove it from there, or override it in your own print stylesheet:

@media print {
  a[href]:after {
    content: none !important;
  }
}

Java: How to convert List to Map

List<Item> list;
Map<Key,Item> map = new HashMap<Key,Item>();
for (Item i : list) map.put(i.getKey(),i);

Assuming of course that each Item has a getKey() method that returns a key of the proper type.

Splitting String and put it on int array

Java 8 offers a streams-based alternative to manual iteration:

int[] intArray = Arrays.stream(input.split(","))
    .mapToInt(Integer::parseInt)
    .toArray();

Be prepared to catch NumberFormatException if it's possible for the input to contain character sequences that cannot be converted to an integer.

Getting byte array through input type = file

This is a long post, but I was tired of all these examples that weren't working for me because they used Promise objects or an errant this that has a different meaning when you are using Reactjs. My implementation was using a DropZone with reactjs, and I got the bytes using a framework similar to what is posted at this following site, when nothing else above would work: https://www.mokuji.me/article/drop-upload-tutorial-1 . There were 2 keys, for me:

  1. You have to get the bytes from the event object, using and during a FileReader's onload function.
  2. I tried various combinations, but in the end, what worked was:

    const bytes = e.target.result.split('base64,')[1];

Where e is the event. React requires const, you could use var in plain Javascript. But that gave me the base64 encoded byte string.

So I'm just going to include the applicable lines for integrating this as if you were using React, because that's how I was building it, but try to also generalize this, and add comments where necessary, to make it applicable to a vanilla Javascript implementation - caveated that I did not use it like that in such a construct to test it.

These would be your bindings at the top, in your constructor, in a React framework (not relevant to a vanilla Javascript implementation):

this.uploadFile = this.uploadFile.bind(this);
this.processFile = this.processFile.bind(this);
this.errorHandler = this.errorHandler.bind(this);
this.progressHandler = this.progressHandler.bind(this);

And you'd have onDrop={this.uploadFile} in your DropZone element. If you were doing this without React, this is the equivalent of adding the onclick event handler you want to run when you click the "Upload File" button.

<button onclick="uploadFile(event);" value="Upload File" />

Then the function (applicable lines... I'll leave out my resetting my upload progress indicator, etc.):

uploadFile(event){
    // This is for React, only
    this.setState({
      files: event,
    });
    console.log('File count: ' + this.state.files.length);

    // You might check that the "event" has a file & assign it like this 
    // in vanilla Javascript:
    // var files = event.target.files;
    // if (!files && files.length > 0)
    //     files = (event.dataTransfer ? event.dataTransfer.files : 
    //            event.originalEvent.dataTransfer.files);

    // You cannot use "files" as a variable in React, however:
    const in_files = this.state.files;

    // iterate, if files length > 0
    if (in_files.length > 0) {
      for (let i = 0; i < in_files.length; i++) {
      // use this, instead, for vanilla JS:
      // for (var i = 0; i < files.length; i++) {
        const a = i + 1;
        console.log('in loop, pass: ' + a);
        const f = in_files[i];  // or just files[i] in vanilla JS

        const reader = new FileReader();
        reader.onerror = this.errorHandler;
        reader.onprogress = this.progressHandler;
        reader.onload = this.processFile(f);
        reader.readAsDataURL(f);
      }      
   }
}

There was this question on that syntax, for vanilla JS, on how to get that file object:

JavaScript/HTML5/jQuery Drag-And-Drop Upload - "Uncaught TypeError: Cannot read property 'files' of undefined"

Note that React's DropZone will already put the File object into this.state.files for you, as long as you add files: [], to your this.state = { .... } in your constructor. I added syntax from an answer on that post on how to get your File object. It should work, or there are other posts there that can help. But all that Q/A told me was how to get the File object, not the blob data, itself. And even if I did fileData = new Blob([files[0]]); like in sebu's answer, which didn't include var with it for some reason, it didn't tell me how to read that blob's contents, and how to do it without a Promise object. So that's where the FileReader came in, though I actually tried and found I couldn't use their readAsArrayBuffer to any avail.

You will have to have the other functions that go along with this construct - one to handle onerror, one for onprogress (both shown farther below), and then the main one, onload, that actually does the work once a method on reader is invoked in that last line. Basically you are passing your event.dataTransfer.files[0] straight into that onload function, from what I can tell.

So the onload method calls my processFile() function (applicable lines, only):

processFile(theFile) {
  return function(e) {
    const bytes = e.target.result.split('base64,')[1];
  }
}

And bytes should have the base64 bytes.

Additional functions:

errorHandler(e){
    switch (e.target.error.code) {
      case e.target.error.NOT_FOUND_ERR:
        alert('File not found.');
        break;
      case e.target.error.NOT_READABLE_ERR:
        alert('File is not readable.');
        break;
      case e.target.error.ABORT_ERR:
        break;    // no operation
      default:
        alert('An error occurred reading this file.');
        break;
    }
  }

progressHandler(e) {
    if (e.lengthComputable){
      const loaded = Math.round((e.loaded / e.total) * 100);
      let zeros = '';

      // Percent loaded in string
      if (loaded >= 0 && loaded < 10) {
        zeros = '00';
      }
      else if (loaded < 100) {
        zeros = '0';
      }

      // Display progress in 3-digits and increase bar length
      document.getElementById("progress").textContent = zeros + loaded.toString();
      document.getElementById("progressBar").style.width = loaded + '%';
    }
  }

And applicable progress indicator markup:

<table id="tblProgress">
  <tbody>
    <tr>
      <td><b><span id="progress">000</span>%</b> <span className="progressBar"><span id="progressBar" /></span></td>
    </tr>                    
  </tbody>
</table>

And CSS:

.progressBar {
  background-color: rgba(255, 255, 255, .1);
  width: 100%;
  height: 26px;
}
#progressBar {
  background-color: rgba(87, 184, 208, .5);
  content: '';
  width: 0;
  height: 26px;
}

EPILOGUE:

Inside processFile(), for some reason, I couldn't add bytes to a variable I carved out in this.state. So, instead, I set it directly to the variable, attachments, that was in my JSON object, RequestForm - the same object as my this.state was using. attachments is an array so I could push multiple files. It went like this:

  const fileArray = [];
  // Collect any existing attachments
  if (RequestForm.state.attachments.length > 0) {
    for (let i=0; i < RequestForm.state.attachments.length; i++) {
      fileArray.push(RequestForm.state.attachments[i]);
    }
  }
  // Add the new one to this.state
  fileArray.push(bytes);
  // Update the state
  RequestForm.setState({
    attachments: fileArray,
  });

Then, because this.state already contained RequestForm:

this.stores = [
  RequestForm,    
]

I could reference it as this.state.attachments from there on out. React feature that isn't applicable in vanilla JS. You could build a similar construct in plain JavaScript with a global variable, and push, accordingly, however, much easier:

var fileArray = new Array();  // place at the top, before any functions

// Within your processFile():
var newFileArray = [];
if (fileArray.length > 0) {
  for (var i=0; i < fileArray.length; i++) {
    newFileArray.push(fileArray[i]);
  }
}
// Add the new one
newFileArray.push(bytes);
// Now update the global variable
fileArray = newFileArray;

Then you always just reference fileArray, enumerate it for any file byte strings, e.g. var myBytes = fileArray[0]; for the first file.

Understanding esModuleInterop in tsconfig file

esModuleInterop generates the helpers outlined in the docs. Looking at the generated code, we can see exactly what these do:

//ts 
import React from 'react'
//js 
var __importDefault = (this && this.__importDefault) || function (mod) {
    return (mod && mod.__esModule) ? mod : { "default": mod };
};
Object.defineProperty(exports, "__esModule", { value: true });
var react_1 = __importDefault(require("react"));

__importDefault: If the module is not an es module then what is returned by require becomes the default. This means that if you use default import on a commonjs module, the whole module is actually the default.

__importStar is best described in this PR:

TypeScript treats a namespace import (i.e. import * as foo from "foo") as equivalent to const foo = require("foo"). Things are simple here, but they don't work out if the primary object being imported is a primitive or a value with call/construct signatures. ECMAScript basically says a namespace record is a plain object.

Babel first requires in the module, and checks for a property named __esModule. If __esModule is set to true, then the behavior is the same as that of TypeScript, but otherwise, it synthesizes a namespace record where:

  1. All properties are plucked off of the require'd module and made available as named imports.
  2. The originally require'd module is made available as a default import.

So we get this:

// ts
import * as React from 'react'

// emitted js
var __importStar = (this && this.__importStar) || function (mod) {
    if (mod && mod.__esModule) return mod;
    var result = {};
    if (mod != null) for (var k in mod) if (Object.hasOwnProperty.call(mod, k)) result[k] = mod[k];
    result["default"] = mod;
    return result;
};
Object.defineProperty(exports, "__esModule", { value: true });
var React = __importStar(require("react"));

allowSyntheticDefaultImports is the companion to all of this, setting this to false will not change the emitted helpers (both of them will still look the same). But it will raise a typescript error if you are using default import for a commonjs module. So this import React from 'react' will raise the error Module '".../node_modules/@types/react/index"' has no default export. if allowSyntheticDefaultImports is false.

Launch custom android application from android browser

For example, You have next things:

A link to open your app: http://example.com

The package name of your app: com.example.mypackage

Then you need to do next:

  1. Add an intent filter to your Activity (Can be any activity you want. For more info check the documentation).

    <activity
         android:name=".MainActivity">
    
         <intent-filter android:label="@string/filter_title_view_app_from_web">
             <action android:name="android.intent.action.VIEW" />
             <category android:name="android.intent.category.DEFAULT" />
             <category android:name="android.intent.category.BROWSABLE" />
             <!-- Accepts URIs that begin with "http://example.com" -->
    
             <data
                 android:host="example.com"
                 android:scheme="http" />
         </intent-filter>
    
         <intent-filter>
             <action android:name="android.intent.action.MAIN" />
             <category android:name="android.intent.category.LAUNCHER" />
         </intent-filter>
    
     </activity> 
    
  2. Create a HTML file to test the link or use this methods.

    Open your Activity directly (just open your Activity, without a choosing dialog).

    Open this link with browser or your programm (by choosing dialog).

  3. Use Mobile Chrome to test

  4. That's it.

And its not necessary to publish app in market to test deep linking =)

Also, for more information, check documentation and useful presentation.

Error 415 Unsupported Media Type: POST not reaching REST if JSON, but it does if XML

Don't return Strings in your methods but Customer objects it self and let JAXB take care of the de/serialization.

Why is this error, 'Sequence contains no elements', happening?

Check again. Use debugger if must. My guess is that for some item in userResponseDetails this query finds no elements:

.Where(y => y.ResponseId.Equals(item.ResponseId))

so you can't call

.First()

on it. Maybe try

.FirstOrDefault()

if it solves the issue.

Do NOT return NULL value! This is purely so that you can see and diagnose where problem is. Handle these cases properly.

Function inside a function.?

function inside a function or so called nested functions are very usable if you need to do some recursion processes such as looping true multiple layer of array or a file tree without multiple loops or sometimes i use it to avoid creating classes for small jobs which require dividing and isolating functionality among multiple functions. but before you go for nested functions you have to understand that

  1. child function will not be available unless the main function is executed
  2. Once main function got executed the child functions will be globally available to access
  3. if you need to call the main function twice it will try to re define the child function and this will throw a fatal error

so is this mean you cant use nested functions? No, you can with the below workarounds

first method is to block the child function being re declaring into global function stack by using conditional block with function exists, this will prevent the function being declared multiple times into global function stack.

function myfunc($a,$b=5){
    if(!function_exists("child")){
        function child($x,$c){
            return $c+$x;   
        }
    }
    
    try{
        return child($a,$b);
    }catch(Exception $e){
        throw $e;
    }
    
}

//once you have invoke the main function you will be able to call the child function
echo myfunc(10,20)+child(10,10);

and the second method will be limiting the function scope of child to local instead of global, to do that you have to define the function as a Anonymous function and assign it to a local variable, then the function will only be available in local scope and will re declared and invokes every time you call the main function.

function myfunc($a,$b=5){
    $child = function ($x,$c){
        return $c+$x;   
    };
    
    try{
        return $child($a,$b);
    }catch(Exception $e){
        throw $e;
    }
    
}

echo myfunc(10,20);

remember the child will not be available outside the main function or global function stack

How does "cat << EOF" work in bash?

Long story short, EOF marker(but a different literal can be used as well) is a heredoc format that allows you to provide your input as multiline. A lot of confusion comes from how cat actually works it seems. You can use cat with >> or > as follows:

$ cat >> temp.txt
line 1
line 2

While cat can be used this way when writing manually into console, it's not convenient if I want to provide the input in a more declarative way so that it can be reused by tools and also to keep indentations, whitespaces, etc.
Heredoc allows to define your entire input as if you are not working with stdin but typing in a separate text editor. This is what Wikipedia article means by:

it is a section of a source code file that is treated as if it were a separate file.

Function to convert timestamp to human date in javascript

This is what I did for the instagram API. converted timestamp with date method by multiplying by 1000. and then added all entity individually like (year, months, etc)

created the custom month list name and mapped with getMonth() method which returns the index of the month.

convertStampDate(unixtimestamp){

// Unixtimestamp

// Months array
var months_arr = ['January','February','March','April','May','June','July','August','September','October','November','December'];

// Convert timestamp to milliseconds
var date = new Date(unixtimestamp*1000);

// Year
var year = date.getFullYear();

// Month
var month = months_arr[date.getMonth()];

// Day
var day = date.getDate();

// Hours
var hours = date.getHours();

// Minutes
var minutes = "0" + date.getMinutes();

// Seconds
var seconds = "0" + date.getSeconds();

// Display date time in MM-dd-yyyy h:m:s format
var fulldate = month+' '+day+'-'+year+' '+hours + ':' + minutes.substr(-2) + ':' + seconds.substr(-2);

// filtered fate
var convdataTime = month+' '+day;
return convdataTime;
}

Call with stamp argument convertStampDate('1382086394000')

and thats it.

How to throw std::exceptions with variable messages?

The following class might come quite handy:

struct Error : std::exception
{
    char text[1000];

    Error(char const* fmt, ...) __attribute__((format(printf,2,3))) {
        va_list ap;
        va_start(ap, fmt);
        vsnprintf(text, sizeof text, fmt, ap);
        va_end(ap);
    }

    char const* what() const throw() { return text; }
};

Usage example:

throw Error("Could not load config file '%s'", configfile.c_str());

How to have a a razor action link open in a new tab?

asp.net mvc ActionLink new tab with angular parameter

<a  target="_blank" class="btn" data-ng-href="@Url.Action("RunReport", "Performance")?hotelCode={{hotel.code}}">Select Room</a>

Application_Start not firing?

A late entry...

To test whether or not the IIS Application gets started before the debugger has had enough time to attach just add this to the top or bottom of your GLOBAL.ASAX's Application_Start.

throw new ApplicationException("Yup, it fired");

Google Maps API v3: How to remove all markers?

To remove all markers from map create functions something like this:

1.addMarker(location): this function used to add marker on map

2.clearMarkers(): this function remove all markers from map, not from array

3.setMapOnAll(map): this function used to add markers info in array

4.deleteMarkers(): this function Deletes all markers in the array by removing references to them.

// Adds a marker to the map and push to the array.
      function addMarker(location) {
        var marker = new google.maps.Marker({
          position: location,
          map: map
        });
        markers.push(marker);
      }


// Sets the map on all markers in the array.
      function setMapOnAll(map) {
        for (var i = 0; i < markers.length; i++) {
          markers[i].setMap(map);
        }
      }



// Removes the markers from the map, but keeps them in the array.
  function clearMarkers() {
    setMapOnAll(null);
  }

// Deletes all markers in the array by removing references to them.
      function deleteMarkers() {
        clearMarkers();
        markers = [];
      }

How get permission for camera in android.(Specifically Marshmallow)

Requesting Permissions In the following code, we will ask for camera permission:

in java

EasyPermissions is a wrapper library to simplify basic system permissions logic when targeting Android M or higher.

Installation EasyPermissions is installed by adding the following dependency to your build.gradle file:

dependencies {

    // For developers using AndroidX in their applications
    implementation 'pub.devrel:easypermissions:3.0.0'

    // For developers using the Android Support Library
    implementation 'pub.devrel:easypermissions:2.0.1'

}


private void askAboutCamera(){

        EasyPermissions.requestPermissions(
                this,
                "A partir deste ponto a permissão de câmera é necessária.",
                CAMERA_REQUEST_CODE,
                Manifest.permission.CAMERA );
}

How do I find where JDK is installed on my windows machine?

Powershell one liner:

$p='HKLM:\SOFTWARE\JavaSoft\Java Development Kit'; $v=(gp $p).CurrentVersion; (gp $p/$v).JavaHome

how to check for special characters php

preg_match('/'.preg_quote('^\'£$%^&*()}{@#~?><,@|-=-_+-¬', '/').'/', $string);

How to get enum value by string or int

I think you forgot the generic type definition:

public T GetEnumValue<T>(int intValue) where T : struct, IConvertible // <T> added

and you can improve it to be most convinient like e.g.:

public static T ToEnum<T>(this string enumValue) : where T : struct, IConvertible
{
    return (T)Enum.Parse(typeof(T), enumValue);
}

then you can do:

TestEnum reqValue = "Value1".ToEnum<TestEnum>();

Android: How to handle right to left swipe gestures

To add an onClick as well, here's what I did.

....
// in OnSwipeTouchListener class

private final class GestureListener extends SimpleOnGestureListener {

    .... // normal GestureListener  code

   @Override
    public boolean onSingleTapConfirmed(MotionEvent e) {
        onClick(); // my method
        return super.onSingleTapConfirmed(e);
    }

} // end GestureListener class

    public void onSwipeRight() {
    }

    public void onSwipeLeft() {
    }

    public void onSwipeTop() {
    }

    public void onSwipeBottom() {
    }

    public void onClick(){ 
    }


    // as normal
    @Override
    public boolean onTouch(View v, MotionEvent event) {
        return gestureDetector.onTouchEvent(event);
}

} // end OnSwipeTouchListener class

I'm using Fragments, so using getActivity() for context. This is how I implemented it - and it works.


myLayout.setOnTouchListener(new OnSwipeTouchListener(getActivity()) {
            public void onSwipeTop() {
                Toast.makeText(getActivity(), "top", Toast.LENGTH_SHORT).show();
            }
            public void onSwipeRight() {
                Toast.makeText(getActivity(), "right", Toast.LENGTH_SHORT).show();
            }
            public void onSwipeLeft() {
                Toast.makeText(getActivity(), "left", Toast.LENGTH_SHORT).show();
            }
            public void onSwipeBottom() {
                Toast.makeText(getActivity(), "bottom", Toast.LENGTH_SHORT).show();
            }

            public void onClick(){
                Toast.makeText(getActivity(), "clicked", Toast.LENGTH_SHORT).show();
            }
        });

How to get scrollbar position with Javascript?

I think the following function can help to have scroll coordinate values:

const getScrollCoordinate = (el = window) => ({
  x: el.pageXOffset || el.scrollLeft,
  y: el.pageYOffset || el.scrollTop,
});

I got this idea from this answer with a little change.

Easiest way to change font and font size

you can change that using label property in property panel. This screen shot is example that

Get index of element as child relative to parent

There's no need to require a big library like jQuery to accomplish this, if you don't want to. To achieve this with built-in DOM manipulation, get a collection of the li siblings in an array, and on click, check the indexOf the clicked element in that array.

_x000D_
_x000D_
const lis = [...document.querySelectorAll('#wizard > li')];_x000D_
lis.forEach((li) => {_x000D_
  li.addEventListener('click', () => {_x000D_
    const index = lis.indexOf(li);_x000D_
    console.log(index);_x000D_
  });_x000D_
});
_x000D_
<ul id="wizard">_x000D_
    <li>Step 1</li>_x000D_
    <li>Step 2</li>_x000D_
</ul>
_x000D_
_x000D_
_x000D_

Or, with event delegation:

_x000D_
_x000D_
const lis = [...document.querySelectorAll('#wizard li')];_x000D_
document.querySelector('#wizard').addEventListener('click', ({ target }) => {_x000D_
  // Make sure the clicked element is a <li> which is a child of wizard:_x000D_
  if (!target.matches('#wizard > li')) return;_x000D_
  _x000D_
  const index = lis.indexOf(target);_x000D_
  console.log(index);_x000D_
});
_x000D_
<ul id="wizard">_x000D_
    <li>Step 1</li>_x000D_
    <li>Step 2</li>_x000D_
</ul>
_x000D_
_x000D_
_x000D_

Or, if the child elements may change dynamically (like with a todo list), then you'll have to construct the array of lis on every click, rather than beforehand:

_x000D_
_x000D_
const wizard = document.querySelector('#wizard');_x000D_
wizard.addEventListener('click', ({ target }) => {_x000D_
  // Make sure the clicked element is a <li>_x000D_
  if (!target.matches('li')) return;_x000D_
  _x000D_
  const lis = [...wizard.children];_x000D_
  const index = lis.indexOf(target);_x000D_
  console.log(index);_x000D_
});
_x000D_
<ul id="wizard">_x000D_
    <li>Step 1</li>_x000D_
    <li>Step 2</li>_x000D_
</ul>
_x000D_
_x000D_
_x000D_

Hiding the address bar of a browser (popup)

There is no definite way to do that. JS may have the API, but the browser vendor may choose not to implement it or implement it in another way.

Also, as far as I remember, Opera even provides the user preferences to prevent JS from making such changes, like have the window move, change status bar content, and stuff like that.

How to create a pivot query in sql server without aggregate function

SELECT *
FROM
(
SELECT [Period], [Account], [Value]
FROM TableName
) AS source
PIVOT
(
    MAX([Value])
    FOR [Period] IN ([2000], [2001], [2002])
) as pvt

Another way,

SELECT ACCOUNT,
      MAX(CASE WHEN Period = '2000' THEN Value ELSE NULL END) [2000],
      MAX(CASE WHEN Period = '2001' THEN Value ELSE NULL END) [2001],
      MAX(CASE WHEN Period = '2002' THEN Value ELSE NULL END) [2002]
FROM tableName
GROUP BY Account

TypeScript hashmap/dictionary interface

The most simple and the correct way is to use Record type Record<string, string>

const myVar : Record<string, string> = {
   key1: 'val1',
   key2: 'val2',
}

Java: print contents of text file to screen

Every example here shows a solution using the FileReader. It is convenient if you do not need to care about a file encoding. If you use some other languages than english, encoding is quite important. Imagine you have file with this text

Príliš žlutoucký kun
úpel dábelské ódy

and the file uses windows-1250 format. If you use FileReader you will get this result:

P??li? ?lu?ou?k? k??
?p?l ??belsk? ?dy

So in this case you would need to specify encoding as Cp1250 (Windows Eastern European) but the FileReader doesn't allow you to do so. In this case you should use InputStreamReader on a FileInputStream.

Example:

String encoding = "Cp1250";
File file = new File("foo.txt");

if (file.exists()) {
    try (BufferedReader br = new BufferedReader(new InputStreamReader(new FileInputStream(file), encoding))) {
        String line = null;
        while ((line = br.readLine()) != null) {
            System.out.println(line);
        }
    } catch (IOException e) {
        e.printStackTrace();
    }
}
else {
    System.out.println("file doesn't exist");
}

In case you want to read the file character after character do not use BufferedReader.

try (InputStreamReader isr = new InputStreamReader(new FileInputStream(file), encoding)) {
    int data = isr.read();
    while (data != -1) {
        System.out.print((char) data);
        data = isr.read();
    }
} catch (IOException e) {
    e.printStackTrace();
}

You need to use a Theme.AppCompat theme (or descendant) with this activity

Instead of all of this, about changing a lot of this in your app.. just do it simple as this video does.

https://www.youtube.com/watch?v=Bsm-BlXo2SI

I already use it so... it's a 100 percent effective.

How to get page content using cURL?

Try This:

$url = "http://www.google.com/search?q=".$strSearch."&hl=en&start=0&sa=N";
  $ch = curl_init();
  curl_setopt($ch, CURLOPT_HEADER, 0);
  curl_setopt($ch, CURLOPT_VERBOSE, 0);
  curl_setopt($ch, CURLOPT_RETURNTRANSFER, true);
  curl_setopt($ch, CURLOPT_USERAGENT, "Mozilla/4.0 (compatible;)");
  curl_setopt($ch, CURLOPT_URL, urlencode($url));
  $response = curl_exec($ch);
  curl_close($ch);

Checking character length in ruby

Ruby provides a built-in function for checking the length of a string. Say it's called s:

if s.length <= 25
  # We're OK
else
  # Too long
end

Java 8 Filter Array Using Lambda

Yes, you can do this by creating a DoubleStream from the array, filtering out the negatives, and converting the stream back to an array. Here is an example:

double[] d = {8, 7, -6, 5, -4};
d = Arrays.stream(d).filter(x -> x > 0).toArray();
//d => [8, 7, 5]

If you want to filter a reference array that is not an Object[] you will need to use the toArray method which takes an IntFunction to get an array of the original type as the result:

String[] a = { "s", "", "1", "", "" };
a = Arrays.stream(a).filter(s -> !s.isEmpty()).toArray(String[]::new);

TypeError: sequence item 0: expected string, int found

Replace

values = ",".join(value_list)

with

values = ','.join([str(i) for i in value_list])

OR

values = ','.join(str(value_list)[1:-1])

Update a submodule to the latest commit

My project should use the 'latest' for the submodule. On Mac OSX 10.11, git version 2.7.1, I did not need to go 'into' my submodule folder in order to collect its commits. I merely did a regular

git pull --rebase 

at the top level, and it correctly updated my submodule.

How do I handle ImeOptions' done button click?

While most people have answered the question directly, I wanted to elaborate more on the concept behind it. First, I was drawn to the attention of IME when I created a default Login Activity. It generated some code for me which included the following:

<EditText
  android:id="@+id/password"
  android:layout_width="match_parent"
  android:layout_height="wrap_content"
  android:hint="@string/prompt_password"
  android:imeActionId="@+id/login"
  android:imeActionLabel="@string/action_sign_in_short"
  android:imeOptions="actionUnspecified"
  android:inputType="textPassword"
  android:maxLines="1"
  android:singleLine="true"/>

You should already be familiar with the inputType attribute. This just informs Android the type of text expected such as an email address, password or phone number. The full list of possible values can be found here.

It was, however, the attribute imeOptions="actionUnspecified" that I didn't understand its purpose. Android allows you to interact with the keyboard that pops up from bottom of screen when text is selected using the InputMethodManager. On the bottom corner of the keyboard, there is a button, typically it says "Next" or "Done", depending on the current text field. Android allows you to customize this using android:imeOptions. You can specify a "Send" button or "Next" button. The full list can be found here.

With that, you can then listen for presses on the action button by defining a TextView.OnEditorActionListener for the EditText element. As in your example:

editText.setOnEditorActionListener(new EditText.OnEditorActionListener() {
    @Override
    public boolean onEditorAction(EditText v, int actionId, KeyEvent event) {
    if (actionId == EditorInfo.IME_ACTION_DONE) {
       //do here your stuff f
       return true;
    }
    return false;
    } 
});

Now in my example I had android:imeOptions="actionUnspecified" attribute. This is useful when you want to try to login a user when they press the enter key. In your Activity, you can detect this tag and then attempt the login:

    mPasswordView = (EditText) findViewById(R.id.password);
    mPasswordView.setOnEditorActionListener(new TextView.OnEditorActionListener() {
        @Override
        public boolean onEditorAction(TextView textView, int id, KeyEvent keyEvent) {
            if (id == R.id.login || id == EditorInfo.IME_NULL) {
                attemptLogin();
                return true;
            }
            return false;
        }
    });

Javascript: output current datetime in YYYY/mm/dd hh:m:sec format

With jQuery date format :

$.format.date(new Date(), 'yyyy/MM/dd HH:mm:ss');

https://github.com/phstc/jquery-dateFormat

Enjoy

ArrayList of int array in java

First of all, for initializing a container you cannot use a primitive type (i.e. int; you can use int[] but as you want just an array of integers, I see no use in that). Instead, you should use Integer, as follows:

ArrayList<Integer> arl = new ArrayList<Integer>();

For adding elements, just use the add function:

arl.add(1);  
arl.add(22);
arl.add(-2);

Last, but not least, for printing the ArrayList you may use the build-in functionality of toString():

System.out.println("Arraylist contains: " + arl.toString());  

If you want to access the i element, where i is an index from 0 to the length of the array-1, you can do a :

int i = 0; // Index 0 is of the first element
System.out.println("The first element is: " + arl.get(i));

I suggest reading first on Java Containers, before starting to work with them.

Import Google Play Services library in Android Studio

After hours of having the same problem, notice that if your jar is on the libs folder will cause problem once you set it upon the "Dependencies ", so i just comment the file tree dependencies and keep the one using

dependencies

//compile fileTree(dir: 'libs', include: ['*.jar'])  <-------- commented one 
compile 'com.google.android.gms:play-services:8.1.0'
compile 'com.android.support:appcompat-v7:22.2.1'

and the problem was solved.

How to update Git clone

If you want to fetch + merge, run

git pull

if you want simply to fetch :

git fetch

HttpContext.Current.User.Identity.Name is Empty

I struggled with this problem the past few days.

I suggest reading Scott Guthrie's blog post Recipe: Enabling Windows Authentication within an Intranet ASP.NET Web application

For me the problem was that although I had Windows Authentication enabled in IIS and I had <authentication mode="Windows" /> in the <system.web> section of web.config, I was not preventing anonymous access. This last part was the key. You need to prevent anonymous access to ensure that the browser sends the credentials.

You can either configure IIS in Control Panel so that your site (or machine) uses Windows authentication and denies anonymous access or you can add the following to your web.config in the system.web section:

<authentication mode="Windows" />

<authorization>
   <deny users="?"/>
</authorization>

npm ERR! network getaddrinfo ENOTFOUND

Make sure to use the latest npm version while installing packages using npm.

While installing JavaScript, mention the latest version of NodeJS. For example, while installing JavaScript using devtools, use the below code:

devtools i --javascript nodejs:10.15.1

This will download and install the mentioned NodeJS version. Try installing the packages with npm after updating the version. This worked for me.

Python pip install module is not found. How to link python to pip location?

If your python and pip binaries are from different versions, modules installed using pip will not be available to python.

Steps to resolve:

  1. Open up a fresh terminal with a default environment and locate the binaries for pip and python.
readlink $(which pip)
../Cellar/python@2/2.7.15_1/bin/pip

readlink $(which python)
/usr/local/bin/python3      <-- another symlink

readlink /usr/local/bin/python3
../Cellar/python/3.7.2/bin/python3

Here you can see an obvious mismatch between the versions 2.7.15_1 and 3.7.2 in my case.

  1. Replace the pip symlink with the pip binary which matches your current version of python. Use your python version in the following command.
ln -is /usr/local/Cellar/python/3.7.2/bin/pip3 $(which pip)

The -i flag promts you to overwrite if the target exists.

That should do the trick.

Function for 'does matrix contain value X?'

Many ways to do this. ismember is the first that comes to mind, since it is a set membership action you wish to take. Thus

X = primes(20);
ismember([15 17],X)
ans =
      0    1

Since 15 is not prime, but 17 is, ismember has done its job well here.

Of course, find (or any) will also work. But these are not vectorized in the sense that ismember was. We can test to see if 15 is in the set represented by X, but to test both of those numbers will take a loop, or successive tests.

~isempty(find(X == 15))
~isempty(find(X == 17))

or,

any(X == 15)
any(X == 17)

Finally, I would point out that tests for exact values are dangerous if the numbers may be true floats. Tests against integer values as I have shown are easy. But tests against floating point numbers should usually employ a tolerance.

tol = 10*eps;
any(abs(X - 3.1415926535897932384) <= tol)

How to "git clone" including submodules?

I had the same problem for a GitHub repository. My account was missing SSH Key. The process is

  1. Generate SSH Key
  2. Adding a new SSH key to your GitHub account

Then, you can clone the repository with submodules (git clone --recursive YOUR-GIT-REPO-URL)

or

Run git submodule init and git submodule update to fetch submodules in already cloned repository.

Android: how to make keyboard enter button say "Search" and handle its click?

by XML:

 <EditText
        android:id="@+id/search_edit"
        android:layout_width="match_parent"
        android:layout_height="wrap_content"
        android:hint="@string/search"
        android:imeOptions="actionSearch"
        android:inputType="text" />

By Java:

 editText.clearFocus();
    InputMethodManager in = (InputMethodManager)getSystemService(Context.INPUT_METHOD_SERVICE);
    in.hideSoftInputFromWindow(searchEditText.getWindowToken(), 0);

Font size relative to the user's screen resolution?

I've created a variant of https://stackoverflow.com/a/17845473/189411

where you can set min and max text size in relation of min and max size of box that you want "check" size. In addition you can check size of dom element different than box where you want apply text size.

You resize text between 19px and 25px on #size-2 element, based on 500px and 960px width of #size-2 element

resizeTextInRange(500,960,19,25,'#size-2');

You resize text between 13px and 20px on #size-1 element, based on 500px and 960px width of body element

resizeTextInRange(500,960,13,20,'#size-1','body');

complete code are there https://github.com/kiuz/sandbox-html-js-css/tree/gh-pages/text-resize-in-range-of-text-and-screen/src

function inRange (x,min,max) {
    return Math.min(Math.max(x, min), max);
}

function resizeTextInRange(minW,maxW,textMinS,textMaxS, elementApply, elementCheck=0) {

    if(elementCheck==0){elementCheck=elementApply;}

    var ww = $(elementCheck).width();
    var difW = maxW-minW;
    var difT = textMaxS- textMinS;
    var rapW = (ww-minW);
    var out=(difT/100)*(rapW/(difW/100))+textMinS;
    var normalizedOut = inRange(out, textMinS, textMaxS);
    $(elementApply).css('font-size',normalizedOut+'px');

    console.log(normalizedOut);

}

$(function () {
    resizeTextInRange(500,960,19,25,'#size-2');
    resizeTextInRange(500,960,13,20,'#size-1','body');
    $(window).resize(function () {
        resizeTextInRange(500,960,19,25,'#size-2');
        resizeTextInRange(500,960,13,20,'#size-1','body');
    });
});

Return background color of selected cell

You can use Cell.Interior.Color, I've used it to count the number of cells in a range that have a given background color (ie. matching my legend).

Import existing Gradle Git project into Eclipse

There is a simplest and quick way to import a Gradle project into Eclipse. Just download the Gradle plugin for Eclipse from here.
https://marketplace.eclipse.org/content/gradle-integration-eclipse-0

And then from import select Gradle and your project would be imported. Then you have to click on Build Model to run it.


EDIT
Above link for Gradle plugin is no more valid. You can use the link as mentioned in the comment by @vikramvi

https://marketplace.eclipse.org/content/buildship-gradle-integration

Regex to replace everything except numbers and a decimal point

Try this:

document.getElementById(target).value = newVal.replace(/^\d+(\.\d{0,2})?$/, "");

Android app unable to start activity componentinfo

Your null pointer exception seems to be on this line:

String url = intent.getExtras().getString("userurl");

because intent.getExtras() returns null when the intent doesn't have any extras.

You have to realize that this piece of code:

Intent Main = new Intent(this, ToClass.class);
Main.putExtra("userurl", url);
startActivity(Main);

doesn't start the activity you wrote in Main.java, it will attempt to start an activity called ToClass and if that doesn't exist, your app crashes.

Also, there is no such thing as "android.intent.action.start" so the manifest should look more like:

<activity android:name=".start" android:label="@string/app_name">
    <intent-filter>
        <action android:name="android.intent.action.MAIN" />
        <category android:name="android.intent.category.LAUNCHER" />
    </intent-filter>
</activity>
<activity android:name= ".Main">
</activity>

I hope this fixes some of the issues you are encountering but I strongly suggest you check out some "getting started" tutorials for android development and build up from there.

Class has no member named

I know this is a year old but I just came across it with the same problem. My problem was that I didn't have a constructor in my implementation file. I think the problem here could be the comment marks at the end of the header file after the #endif...

Change Color of Fonts in DIV (CSS)

To do links, you can do

.social h2 a:link {
  color: pink;
  font-size: 14px;   
}

You can change the hover, visited, and active link styling too. Just replace "link" with what you want to style. You can learn more at the w3schools page CSS Links.

Open terminal here in Mac OS finder

Ok, I realize that this is a bit late... maybe this alternative wasn't available at the moment of writing the post?

Anyway, I've found installing the pos package via Fink (a prerequisite in this case, maybe there is something similar for those who uses MacPorts?) to be the easiest solution. You get two commands:

  1. posd - which gives the current directory of the frontmost Finder window (for which you presumably make an alias cdf=cd posd)
  2. fdc - which switches the current directory of the frontmost Finder window to the Terminal pwd. This is slightly different from 'open .' which always opens a new finder window.

Yes, you have to switch to the Terminal window before writing cdf, but I suppose that's quite cheap comparing to clicking a button in the Finder toolbar. And it works with iTerm as well, you don't have to download a separate Finder toolbar button that opens an iTerm window. This is the same approach as proposed by PCheese, but you don't have to clutter your .bash_profile.

What is the "Upgrade-Insecure-Requests" HTTP header?

Short answer: it's closely related to the Content-Security-Policy: upgrade-insecure-requests response header, indicating that the browser supports it (and in fact prefers it).

It took me 30mins of Googling, but I finally found it buried in the W3 spec.

The confusion comes because the header in the spec was HTTPS: 1, and this is how Chromium implemented it, but after this broke lots of websites that were poorly coded (particularly WordPress and WooCommerce) the Chromium team apologized:

"I apologize for the breakage; I apparently underestimated the impact based on the feedback during dev and beta."
— Mike West, in Chrome Issue 501842

Their fix was to rename it to Upgrade-Insecure-Requests: 1, and the spec has since been updated to match.

Anyway, here is the explanation from the W3 spec (as it appeared at the time)...

The HTTPS HTTP request header field sends a signal to the server expressing the client’s preference for an encrypted and authenticated response, and that it can successfully handle the upgrade-insecure-requests directive in order to make that preference as seamless as possible to provide.

...

When a server encounters this preference in an HTTP request’s headers, it SHOULD redirect the user to a potentially secure representation of the resource being requested.

When a server encounters this preference in an HTTPS request’s headers, it SHOULD include a Strict-Transport-Security header in the response if the request’s host is HSTS-safe or conditionally HSTS-safe [RFC6797].

How do I get the classes of all columns in a data frame?

Hello was looking for the same, and it could be also

unlist(lapply(mtcars,class))

SqlBulkCopy - The given value of type String from the data source cannot be converted to type money of the specified target column

For the people stumbling across this question and getting a similar error message in regards to an nvarchar instead of money:

The given value of type String from the data source cannot be converted to type nvarchar of the specified target column.

This could be caused by a too-short column.

For example, if your column is defined as nvarchar(20) and you have a 40 character string, you may get this error.

Source

Removing a non empty directory programmatically in C or C++

How to delete a non empty folder using unlinkat() in c?

Here is my work on it:

    /*
     * Program to erase the files/subfolders in a directory given as an input
     */

    #include <stdio.h>
    #include <stdlib.h>
    #include <string.h>
    #include <dirent.h>
    #include <unistd.h>
    #include <sys/types.h>
    #include <sys/stat.h>
    #include <fcntl.h>
    void remove_dir_content(const char *path)
    {
        struct dirent *de;
        char fname[300];
        DIR *dr = opendir(path);
        if(dr == NULL)
        {
            printf("No file or directory found\n");
            return;
        }
        while((de = readdir(dr)) != NULL)
        {
            int ret = -1;
            struct stat statbuf;
            sprintf(fname,"%s/%s",path,de->d_name);
            if (!strcmp(de->d_name, ".") || !strcmp(de->d_name, ".."))
                        continue;
            if(!stat(fname, &statbuf))
            {
                if(S_ISDIR(statbuf.st_mode))
                {
                    printf("Is dir: %s\n",fname);
                    printf("Err: %d\n",ret = unlinkat(dirfd(dr),fname,AT_REMOVEDIR));
                    if(ret != 0)
                    {
                        remove_dir_content(fname);
                        printf("Err: %d\n",ret = unlinkat(dirfd(dr),fname,AT_REMOVEDIR));
                    }
                }
                else
                {
                    printf("Is file: %s\n",fname);
                    printf("Err: %d\n",unlink(fname));
                }
            }
        }
        closedir(dr);
    }
    void main()
    {
        char str[10],str1[20] = "../",fname[300]; // Use str,str1 as your directory path where it's files & subfolders will be deleted.
        printf("Enter the dirctory name: ");
        scanf("%s",str);
        strcat(str1,str);
        printf("str1: %s\n",str1);
        remove_dir_content(str1); //str1 indicates the directory path
    }

css rotate a pseudo :after or :before content:""

.process-list:after{
    content: "\2191";
    position: absolute;
    top:50%;
    right:-8px;
    background-color: #ea1f41;
    width:35px;
    height: 35px;
    border:2px solid #ffffff;
    border-radius: 5px;
    color: #ffffff;
    z-index: 10000;
    -webkit-transform: rotate(50deg) translateY(-50%);
    -moz-transform: rotate(50deg) translateY(-50%);
    -ms-transform: rotate(50deg) translateY(-50%);
    -o-transform: rotate(50deg) translateY(-50%);
    transform: rotate(50deg) translateY(-50%);
}

you can check this code . i hope you will easily understand.

How to change permissions for a folder and its subfolders/files in one step?

For anyone still struggling with permission issues, navigate up one directory level cd .. from the root directory of your project, then add yourself (user) to the directory and give permission to edit everything inside (tested on Mac OS).

To do that you would run this command (preferred):

sudo chown -R username: foldername .*

note: for currently unsaved changes, might need to restart the code editor first to be able to save without being asked for a password.

Also, please remember you can press tab to see the options while typing username and folder to make it easier for yourself.


or simply:

sudo chmod -R 755 foldername

but as mentioned above, need to be careful with the second method.

Getting Django admin url for an object

For pre 1.1 django it is simple (for default admin site instance):

reverse('admin_%s_%s_change' % (app_label, model_name), args=(object_id,))

How to create a sleep/delay in nodejs that is Blocking?

Node is asynchronous by nature, and that's what's great about it, so you really shouldn't be blocking the thread, but as this seems to be for a project controlling LED's, I'll post a workaraound anyway, even if it's not a very good one and shouldn't be used (seriously).

A while loop will block the thread, so you can create your own sleep function

function sleep(time, callback) {
    var stop = new Date().getTime();
    while(new Date().getTime() < stop + time) {
        ;
    }
    callback();
}

to be used as

sleep(1000, function() {
   // executes after one second, and blocks the thread
});

I think this is the only way to block the thread (in principle), keeping it busy in a loop, as Node doesn't have any blocking functionality built in, as it would sorta defeat the purpose of the async behaviour.

python: how to get information about a function?

In python: help(my_list.append) for example, will give you the docstring of the function.

>>> my_list = []
>>> help(my_list.append)

    Help on built-in function append:

    append(...)
        L.append(object) -- append object to end

How to upload and parse a CSV file in php

You want the handling file uploads section of the PHP manual, and you would also do well to look at fgetcsv() and explode().

iPhone App Icons - Exact Radius?

The corner radius of the 57 x 57 pixel icon is 9 pixels.

How do I remove duplicate items from an array in Perl?

My usual way of doing this is:

my %unique = ();
foreach my $item (@myarray)
{
    $unique{$item} ++;
}
my @myuniquearray = keys %unique;

If you use a hash and add the items to the hash. You also have the bonus of knowing how many times each item appears in the list.

How to copy part of an array to another array in C#?

Note: I found this question looking for one of the steps in the answer to how to resize an existing array.

So I thought I would add that information here, in case anyone else was searching for how to do a ranged copy as a partial answer to the question of resizing an array.

For anyone else finding this question looking for the same thing I was, it is very simple:

Array.Resize<T>(ref arrayVariable, newSize);

where T is the type, i.e. where arrayVariable is declared:

T[] arrayVariable;

That method handles null checks, as well as newSize==oldSize having no effect, and of course silently handles the case where one of the arrays is longer than the other.

See the MSDN article for more.

Running CMake on Windows

The default generator for Windows seems to be set to NMAKE. Try to use:

cmake -G "MinGW Makefiles"

Or use the GUI, and select MinGW Makefiles when prompted for a generator. Don't forget to cleanup the directory where you tried to run CMake, or delete the cache in the GUI. Otherwise, it will try again with NMAKE.

How can I generate a unique ID in Python?

here you can find an implementation :

def __uniqueid__():
    """
      generate unique id with length 17 to 21.
      ensure uniqueness even with daylight savings events (clocks adjusted one-hour backward).

      if you generate 1 million ids per second during 100 years, you will generate 
      2*25 (approx sec per year) * 10**6 (1 million id per sec) * 100 (years) = 5 * 10**9 unique ids.

      with 17 digits (radix 16) id, you can represent 16**17 = 295147905179352825856 ids (around 2.9 * 10**20).
      In fact, as we need far less than that, we agree that the format used to represent id (seed + timestamp reversed)
      do not cover all numbers that could be represented with 35 digits (radix 16).

      if you generate 1 million id per second with this algorithm, it will increase the seed by less than 2**12 per hour
      so if a DST occurs and backward one hour, we need to ensure to generate unique id for twice times for the same period.
      the seed must be at least 1 to 2**13 range. if we want to ensure uniqueness for two hours (100% contingency), we need 
      a seed for 1 to 2**14 range. that's what we have with this algorithm. You have to increment seed_range_bits if you
      move your machine by airplane to another time zone or if you have a glucky wallet and use a computer that can generate
      more than 1 million ids per second.

      one word about predictability : This algorithm is absolutely NOT designed to generate unpredictable unique id.
      you can add a sha-1 or sha-256 digest step at the end of this algorithm but you will loose uniqueness and enter to collision probability world.
      hash algorithms ensure that for same id generated here, you will have the same hash but for two differents id (a pair of ids), it is
      possible to have the same hash with a very little probability. You would certainly take an option on a bijective function that maps
      35 digits (or more) number to 35 digits (or more) number based on cipher block and secret key. read paper on breaking PRNG algorithms 
      in order to be convinced that problems could occur as soon as you use random library :)

      1 million id per second ?... on a Intel(R) Core(TM)2 CPU 6400 @ 2.13GHz, you get :

      >>> timeit.timeit(uniqueid,number=40000)
      1.0114529132843018

      an average of 40000 id/second
    """
    mynow=datetime.now
    sft=datetime.strftime
    # store old datetime each time in order to check if we generate during same microsecond (glucky wallet !)
    # or if daylight savings event occurs (when clocks are adjusted backward) [rarely detected at this level]
    old_time=mynow() # fake init - on very speed machine it could increase your seed to seed + 1... but we have our contingency :)
    # manage seed
    seed_range_bits=14 # max range for seed
    seed_max_value=2**seed_range_bits - 1 # seed could not exceed 2**nbbits - 1
    # get random seed
    seed=random.getrandbits(seed_range_bits)
    current_seed=str(seed)
    # producing new ids
    while True:
        # get current time 
        current_time=mynow()
        if current_time <= old_time:
            # previous id generated in the same microsecond or Daylight saving time event occurs (when clocks are adjusted backward)
            seed = max(1,(seed + 1) % seed_max_value)
            current_seed=str(seed)
        # generate new id (concatenate seed and timestamp as numbers)
        #newid=hex(int(''.join([sft(current_time,'%f%S%M%H%d%m%Y'),current_seed])))[2:-1]
        newid=int(''.join([sft(current_time,'%f%S%M%H%d%m%Y'),current_seed]))
        # save current time
        old_time=current_time
        # return a new id
        yield newid

""" you get a new id for each call of uniqueid() """
uniqueid=__uniqueid__().next

import unittest
class UniqueIdTest(unittest.TestCase):
    def testGen(self):
        for _ in range(3):
            m=[uniqueid() for _ in range(10)]
            self.assertEqual(len(m),len(set(m)),"duplicates found !")

hope it helps !

ssh: Could not resolve hostname github.com: Name or service not known; fatal: The remote end hung up unexpectedly

Recently, I have seen this problem too. Below, you have my solution:

  1. ping github.com, if ping failed. it is DNS error.
  2. sudo vim /etc/resolv.conf, the add: nameserver 8.8.8.8 nameserver 8.8.4.4

Or it can be a genuine network issue. Restart your network-manager using sudo service network-manager restart or fix it up


I have just received this error after switching from HTTPS to SSH (for my origin remote). To fix, I simply ran the following command (for each repo):

ssh -T [email protected]

Upon receiving a successful response, I could fetch/push to the repo with ssh.

I took that command from Git's Testing your SSH connection guide, which is part of the greater Connecting to GitHub with with SSH guide.

Can I call curl_setopt with CURLOPT_HTTPHEADER multiple times to set multiple headers?

/**
 * If $header is an array of headers
 * It will format and return the correct $header
 * $header = [
 *  'Accept' => 'application/json',
 *  'Content-Type' => 'application/x-www-form-urlencoded'
 * ];
 */
$i_header = $header;
if(is_array($i_header) === true){
    $header = [];
    foreach ($i_header as $param => $value) {
        $header[] = "$param: $value";
    }
}

Getting the last argument passed to a shell script

Just use !$.

$ mkdir folder
$ cd !$ # will run: cd folder

Check if one date is between two dates

Date.parse supports the format mm/dd/yyyy not dd/mm/yyyy. For the latter, either use a library like moment.js or do something as shown below

var dateFrom = "02/05/2013";
var dateTo = "02/09/2013";
var dateCheck = "02/07/2013";

var d1 = dateFrom.split("/");
var d2 = dateTo.split("/");
var c = dateCheck.split("/");

var from = new Date(d1[2], parseInt(d1[1])-1, d1[0]);  // -1 because months are from 0 to 11
var to   = new Date(d2[2], parseInt(d2[1])-1, d2[0]);
var check = new Date(c[2], parseInt(c[1])-1, c[0]);

console.log(check > from && check < to)

Add padding to HTML text input field

padding-right works for me in Firefox/Chrome on Windows but not in IE. Welcome to the wonderful world of IE standards non-compliance.

See: http://jsfiddle.net/SfPju/466/

HTML

<input type="text" class="foo" value="abcdefghijklmnopqrstuvwxyz"/>

CSS

.foo
{
    padding-right: 20px;
}

How to create a date object from string in javascript

You definitely want to use the second expression since months in JS are enumerated from 0.

Also you may use Date.parse method, but it uses different date format:

var timestamp = Date.parse("11/30/2011");
var dateObject = new Date(timestamp);

What is SELF JOIN and when would you use it?

You use a self join when a table references data in itself.

E.g., an Employee table may have a SupervisorID column that points to the employee that is the boss of the current employee.

To query the data and get information for both people in one row, you could self join like this:

select e1.EmployeeID, 
    e1.FirstName, 
    e1.LastName,
    e1.SupervisorID, 
    e2.FirstName as SupervisorFirstName, 
    e2.LastName as SupervisorLastName
from Employee e1
left outer join Employee e2 on e1.SupervisorID = e2.EmployeeID

Detect whether Office is 32bit or 64bit via the registry

Outlook Bitness registry key does not exist on my machine.

One way to determine Outlook Bitness is by examining Outlook.exe, itself and determine if it is 32bit or 64bit.

Specifically, you can check the [IMAGE_FILE_HEADER.Machine][1] type and this will return a value indicating processor type.

For an excellent background of this discussion, on reading the PE Header of a file read this (outdated link), which states;

The IMAGE_NT_HEADERS structure is the primary location where specifics of the PE file are stored. Its offset is given by the e_lfanew field in the IMAGE_DOS_HEADER at the beginning of the file. There are actually two versions of the IMAGE_NT_HEADER structure, one for 32-bit executables and the other for 64-bit versions. The differences are so minor that I'll consider them to be the same for the purposes of this discussion. The only correct, Microsoft-approved way of differentiating between the two formats is via the value of the Magic field in the IMAGE_OPTIONAL_HEADER (described shortly).

An IMAGE_NT_HEADER is comprised of three fields:

typedef struct _IMAGE_NT_HEADERS { DWORD Signature; IMAGE_FILE_HEADER FileHeader; IMAGE_OPTIONAL_HEADER32 OptionalHeader; } IMAGE_NT_HEADERS32, *PIMAGE_NT_HEADERS32;

and you can get the c# code here.

The Magic field is at the start of the IMAGE_OPTIONAL_HEADER structure, 2 bytes at offset 24 from the start of the _IMAGE_NT_HEADERS. It has values of 0x10B for 32-bit and 0x20B for 64-bit.

Youtube API Limitations

Version 3 of the YouTube Data API has concrete quota numbers listed in the Google API Console where you register for your API Key. You can use 10,000 units per day. Projects that had enabled the YouTube Data API before April 20, 2016, have a default quota of 50M/day.

You can read about what a unit is here: https://developers.google.com/youtube/v3/getting-started#quota

  • A simple read operation that only retrieves the ID of each returned resource has a cost of approximately 1 unit.
  • A write operation has a cost of approximately 50 units.
  • A video upload has a cost of approximately 1600 units.

If you hit the limits, Google will stop returning results until your quota is reset. You can apply for more than 1M requests per day, but you will have to pay for those extra requests.

Also, you can read about why Google has deferred support to StackOverflow on their YouTube blog here: https://youtube-eng.googleblog.com/2012/09/the-youtube-api-on-stack-overflow_14.html

There are a number of active members on the YouTube Developer Relations team here including Jeff Posnick, Jarek Wilkiewicz, and Ibrahim Ulukaya who all have knowledge of Youtube internals...

UPDATE: Increased the quota numbers to reflect current limits on December 10, 2013.

UPDATE: Decreased the quota numbers from 50M to 1M per day to reflect current limits on May 13, 2016.

UPDATE: Decreased the quota numbers from 1M to 10K per day as of January 11, 2019.

How do I check if a string contains another string in Objective-C?

An improved version of P i's solution, a category on NSString, that not only will tell, if a string is found within another string, but also takes a range by reference, is:

@interface NSString (Contains)
-(BOOL)containsString: (NSString*)substring
              atRange:(NSRange*)range;

-(BOOL)containsString:(NSString *)substring;
@end

@implementation NSString (Contains)

-(BOOL)containsString:(NSString *)substring
              atRange:(NSRange *)range{

    NSRange r = [self rangeOfString : substring];
    BOOL found = ( r.location != NSNotFound );
    if (range != NULL) *range = r;
    return found;
}

-(BOOL)containsString:(NSString *)substring
{
    return [self containsString:substring
                        atRange:NULL];
}

@end

Use it like:

NSString *string = @"Hello, World!";

//If you only want to ensure a string contains a certain substring
if ([string containsString:@"ello" atRange:NULL]) {
    NSLog(@"YES");
}

// Or simply
if ([string containsString:@"ello"]) {
    NSLog(@"YES");
}

//If you also want to know substring's range
NSRange range;
if ([string containsString:@"ello" atRange:&range]) {
    NSLog(@"%@", NSStringFromRange(range));
}

Why functional languages?

Functional programming has been around for a long time, since LISP was one of the earliest languages to have a compiler, and since MIT's LISP machines. It's not a new paradigm (OO is much newer) but the dominant software platforms have tended to be written in languages that translate easily to assembly language, and their APIs heavily favor imperative code (UNIX with C, Windows with C, and Macintosh with Pascal and later C).

I think the new innovation in the last few years is for a diversity of APIs to catch on, particularly for things like web development where the platform APIs are irrelevant. Since you're not coding directly to the Win32 API or the POSIX API, that gives people the freedom to try out functional languages.

How to clear cache in Yarn?

Run yarn cache clean.


Run yarn help cache in your bash, and you will see:

Usage: yarn cache [ls|clean] [flags]

Options: -h, --help output usage information -V, --version output the version number --offline
--prefer-offline
--strict-semver
--json
--global-folder [path]
--modules-folder [path] rather than installing modules into the node_modules folder relative to the cwd, output them here
--packages-root [path] rather than storing modules into a global packages root, store them here
--mutex [type][:specifier] use a mutex to ensure only one yarn instance is executing

Visit http://yarnpkg.com/en/docs/cli/cache for documentation about this command.

Multiple aggregate functions in HAVING clause

For your example query, the only possible value greater than 2 and less than 4 is 3, so we simplify:

GROUP BY meetingID
HAVING COUNT(caseID) = 3

In your general case:

GROUP BY meetingID
HAVING COUNT(caseID) > x AND COUNT(caseID) < 7

Or (possibly easier to read?),

GROUP BY meetingID
HAVING COUNT(caseID) BETWEEN x+1 AND 6

How do I get the total Json record count using JQuery?

What you're looking for is

j.d.length

The d is the key. At least it is in my case, I'm using a .NET webservice.

 $.ajax({
            type: "POST",
            url: "CantTellU.asmx",
            data: "{'userID' : " + parseInt($.query.get('ID')) + " }",
            contentType: "application/json; charset=utf-8",
            dataType: "json",
            success: function(msg, status) {
                ApplyTemplate(msg);
                alert(msg.d.length);
            }
        });

.htaccess redirect www to non-www with SSL/HTTPS

www to non www with https

RewriteEngine on

RewriteCond %{HTTP_HOST} ^www\.(.*)$ [NC]
RewriteRule ^(.*)$ https://%1/$1 [R=301,L]

RewriteCond %{ENV:HTTPS} !on
RewriteRule ^(.*)$ https://%{HTTP_HOST}%{REQUEST_URI} [R=301,L]

How to change a <select> value from JavaScript

document.getElementById("select").selectedIndex = 0 will work

How to get a subset of a javascript object's properties

  1. convert arguments to array

  2. use Array.forEach() to pick the property

    Object.prototype.pick = function(...args) {
       var obj = {};
       args.forEach(k => obj[k] = this[k])
       return obj
    }
    var a = {0:"a",1:"b",2:"c"}
    var b = a.pick('1','2')  //output will be {1: "b", 2: "c"}
    

Android MediaPlayer Stop and Play

To stop the Media Player without the risk of an Illegal State Exception, you must do

  try {
        mp.reset();
        mp.prepare();
        mp.stop();
        mp.release();
        mp=null;
       }
  catch (Exception e)
         {
           e.printStackTrace();
         }

rather than just

try {
       mp.stop();
       mp.release();
       mp=null;
    } 
catch (Exception e) 
    {
      e.printStackTrace();
    }

CHECK constraint in MySQL is not working

The CHECK constraint doesn't seem to be implemented in MySQL.

See this bug report: https://bugs.mysql.com/bug.php?id=3464

How can I output a UTF-8 CSV in PHP that Excel will read properly?

In my case following works very nice to make CSV file with UTF-8 chars displayed correctly in Excel.

$out = fopen('php://output', 'w');
fprintf($out, chr(0xEF).chr(0xBB).chr(0xBF));
fputcsv($out, $some_csv_strings);

The 0xEF 0xBB 0xBF BOM header will let Excel know the correct encoding.

where does MySQL store database files?

another way from MySQL Workbench:

enter image description here

TypeError: unhashable type: 'dict'

A possible solution might be to use the JSON dumps() method, so you can convert the dictionary to a string ---

import json

a={"a":10, "b":20}
b={"b":20, "a":10}
c = [json.dumps(a), json.dumps(b)]


set(c)
json.dumps(a) in c

Output -

set(['{"a": 10, "b": 20}'])
True

Uninitialized Constant MessagesController

Your model is @Messages, change it to @message.

To change it like you should use migration:

def change   rename_table :old_table_name, :new_table_name end 

Of course do not create that file by hand but use rails generator:

rails g migration ChangeMessagesToMessage 

That will generate new file with proper timestamp in name in 'db dir. Then run:

rake db:migrate 

And your app should be fine since then.

How to pass in password to pg_dump?

Backup over ssh with password using temporary .pgpass credentials and push to S3:

#!/usr/bin/env bash
cd "$(dirname "$0")"

DB_HOST="*******.*********.us-west-2.rds.amazonaws.com"
DB_USER="*******"
SSH_HOST="[email protected]_domain.com"
BUCKET_PATH="bucket_name/backup"

if [ $# -ne 2 ]; then
    echo "Error: 2 arguments required"
    echo "Usage:"
    echo "  my-backup-script.sh <DB-name> <password>"
    echo "  <DB-name> = The name of the DB to backup"
    echo "  <password> = The DB password, which is also used for GPG encryption of the backup file"
    echo "Example:"
    echo "  my-backup-script.sh my_db my_password"
    exit 1
fi

DATABASE=$1
PASSWORD=$2

echo "set remote PG password .."
echo "$DB_HOST:5432:$DATABASE:$DB_USER:$PASSWORD" | ssh "$SSH_HOST" "cat > ~/.pgpass; chmod 0600 ~/.pgpass"
echo "backup over SSH and gzip the backup .."
ssh "$SSH_HOST" "pg_dump -U $DB_USER -h $DB_HOST -C --column-inserts $DATABASE" | gzip > ./tmp.gz
echo "unset remote PG password .."
echo "*********" | ssh "$SSH_HOST" "cat > ~/.pgpass"
echo "encrypt the backup .."
gpg --batch --passphrase "$PASSWORD" --cipher-algo AES256 --compression-algo BZIP2 -co "$DATABASE.sql.gz.gpg" ./tmp.gz

# Backing up to AWS obviously requires having your credentials to be set locally
# EC2 instances can use instance permissions to push files to S3
DATETIME=`date "+%Y%m%d-%H%M%S"`
aws s3 cp ./"$DATABASE.sql.gz.gpg" s3://"$BUCKET_PATH"/"$DATABASE"/db/"$DATETIME".sql.gz.gpg
# s3 is cheap, so don't worry about a little temporary duplication here
# "latest" is always good to have because it makes it easier for dev-ops to use
aws s3 cp ./"$DATABASE.sql.gz.gpg" s3://"$BUCKET_PATH"/"$DATABASE"/db/latest.sql.gz.gpg

echo "local clean-up .."
rm ./tmp.gz
rm "$DATABASE.sql.gz.gpg"

echo "-----------------------"
echo "To decrypt and extract:"
echo "-----------------------"
echo "gpg -d ./$DATABASE.sql.gz.gpg | gunzip > tmp.sql"
echo

Just substitute the first couple of config lines with whatever you need - obviously. For those not interested in the S3 backup part, take it out - obviously.

This script deletes the credentials in .pgpass afterward because in some environments, the default SSH user can sudo without a password, for example an EC2 instance with the ubuntu user, so using .pgpass with a different host account in order to secure those credential, might be pointless.

docker unauthorized: authentication required - upon push with successful login

Try docker logout first, then relogin with docker login

Primitive type 'short' - casting in Java

Any data type which is lower than "int" (except Boolean) is implicitly converts to "int".

In your case:

short a = 2;
short b = 3;
short c = a + b;

The result of (a+b) is implicitly converted to an int. And now you are assigning it to "short".So that you are getting the error.

short,byte,char --for all these we will get same error.

SQL Update Multiple Fields FROM via a SELECT Statement

You should be able to do something along the lines of the following

UPDATE s
SET
    OrgAddress1 = bd.OrgAddress1,
    OrgAddress2 = bd.OrgAddress2,
    ...
    DestZip = bd.DestZip
FROM
    Shipment s, ProfilerTest.dbo.BookingDetails bd
WHERE
    bd.MyID = @MyId AND s.MyID2 = @MyID2

FROM statement can be made more optimial (using more specific joins), but the above should do the trick. Also, a nice side benefit to writing it this way, to see a preview of the UPDATE change UPDATE s SET to read SELECT! You will then see that data as it would appear if the update had taken place.

Create a sample login page using servlet and JSP?

You aren't really using the doGet() method. When you're opening the page, it issues a GET request, not POST.

Try changing doPost() to service() instead... then you're using the same method to handle GET and POST requests.

...

What is the difference between "expose" and "publish" in Docker?

Short answer:

  • EXPOSE is a way of documenting
  • --publish (or -p) is a way of mapping a host port to a running container port

Notice below that:

  • EXPOSE is related to Dockerfiles ( documenting )
  • --publish is related to docker run ... ( execution / run-time )

Exposing and publishing ports

In Docker networking, there are two different mechanisms that directly involve network ports: exposing and publishing ports. This applies to the default bridge network and user-defined bridge networks.

  • You expose ports using the EXPOSE keyword in the Dockerfile or the --expose flag to docker run. Exposing ports is a way of documenting which ports are used, but does not actually map or open any ports. Exposing ports is optional.

  • You publish ports using the --publish or --publish-all flag to docker run. This tells Docker which ports to open on the container’s network interface. When a port is published, it is mapped to an available high-order port (higher than 30000) on the host machine, unless you specify the port to map to on the host machine at runtime. You cannot specify the port to map to on the host machine when you build the image (in the Dockerfile), because there is no way to guarantee that the port will be available on the host machine where you run the image.

from: Docker container networking

Update October 2019: the above piece of text is no longer in the docs but an archived version is here: docs.docker.com/v17.09/engine/userguide/networking/#exposing-and-publishing-ports

Maybe the current documentation is the below:

Published ports

By default, when you create a container, it does not publish any of its ports to the outside world. To make a port available to services outside of Docker, or to Docker containers which are not connected to the container's network, use the --publish or -p flag. This creates a firewall rule which maps a container port to a port on the Docker host.

and can be found here: docs.docker.com/config/containers/container-networking/#published-ports

Also,

EXPOSE

...The EXPOSE instruction does not actually publish the port. It functions as a type of documentation between the person who builds the image and the person who runs the container, about which ports are intended to be published.

from: Dockerfile reference






Service access when EXPOSE / --publish are not defined:

At @Golo Roden's answer it is stated that::

"If you do not specify any of those, the service in the container will not be accessible from anywhere except from inside the container itself."

Maybe that was the case at the time the answer was being written, but now it seems that even if you do not use EXPOSE or --publish, the host and other containers of the same network will be able to access a service you may start inside that container.

How to test this:

I've used the following Dockerfile. Basically, I start with ubuntu and install a tiny web-server:

FROM ubuntu
RUN apt-get update && apt-get install -y mini-httpd

I build the image as "testexpose" and run a new container with:

docker run --rm -it testexpose bash

Inside the container, I launch a few instances of mini-httpd:

root@fb8f7dd1322d:/# mini_httpd -p 80
root@fb8f7dd1322d:/# mini_httpd -p 8080
root@fb8f7dd1322d:/# mini_httpd -p 8090

I am then able to use curl from the host or other containers to fetch the home page of mini-httpd.


Further reading

Very detailed articles on the subject by Ivan Pepelnjak:

How to list all the available keyspaces in Cassandra?

[cqlsh 4.1.0 | Cassandra 2.0.4 | CQL spec 3.1.1 | Thrift protocol 19.39.0]

Currently, the command to use is:

DESCRIBE keyspaces;

First Heroku deploy failed `error code=H10`

I got the same above error as "app crashed" and H10 error and the heroku app logs is not showing much info related to the error msg reasons. Then I restarted the dynos in heroku and then it showed the error saying additional curly brace in one of the index.js files in my setup. The issue got fixed once it is removed and redeployed the app on heroku.

NullPointerException in Java with no StackTrace

Here is an explanation : Hotspot caused exceptions to lose their stack traces in production – and the fix

I've tested it on Mac OS X

  • java version "1.6.0_26"
  • Java(TM) SE Runtime Environment (build 1.6.0_26-b03-383-11A511)
  • Java HotSpot(TM) 64-Bit Server VM (build 20.1-b02-383, mixed mode)

    Object string = "abcd";
    int i = 0;
    while (i < 12289) {
        i++;
        try {
            Integer a = (Integer) string;
        } catch (Exception e) {
            e.printStackTrace();
        }
    }
    

For this specific fragment of code, 12288 iterations (+frequency?) seems to be the limit where JVM has decided to use preallocated exception...

How does one create an InputStream from a String?

Instead of CharSet.forName, using com.google.common.base.Charsets from Google's Guava (http://code.google.com/p/guava-libraries/wiki/StringsExplained#Charsets) is is slightly nicer:

InputStream is = new ByteArrayInputStream( myString.getBytes(Charsets.UTF_8) );

Which CharSet you use depends entirely on what you're going to do with the InputStream, of course.

What is the 'open' keyword in Swift?

open is only for another module for example: cocoa pods, or unit test, we can inherit or override

Invert colors of an image in CSS or JavaScript

Can be done in major new broswers using the code below

.img {
    -webkit-filter:invert(100%);
     filter:progid:DXImageTransform.Microsoft.BasicImage(invert='1');
}

However, if you want it to work across all browsers you need to use Javascript. Something like this gist will do the job.

React.js: onChange event for contentEditable

Edit 2015

Someone has made a project on NPM with my solution: https://github.com/lovasoa/react-contenteditable

Edit 06/2016: I've just encoutered a new problem that occurs when the browser tries to "reformat" the html you just gave him, leading to component always re-rendering. See

Edit 07/2016: here's my production contentEditable implementation. It has some additional options over react-contenteditable that you might want, including:

  • locking
  • imperative API allowing to embed html fragments
  • ability to reformat the content

Summary:

FakeRainBrigand's solution has worked quite fine for me for some time until I got new problems. ContentEditables are a pain, and are not really easy to deal with React...

This JSFiddle demonstrates the problem.

As you can see, when you type some characters and click on Clear, the content is not cleared. This is because we try to reset the contenteditable to the last known virtual dom value.

So it seems that:

  • You need shouldComponentUpdate to prevent caret position jumps
  • You can't rely on React's VDOM diffing algorithm if you use shouldComponentUpdate this way.

So you need an extra line so that whenever shouldComponentUpdate returns yes, you are sure the DOM content is actually updated.

So the version here adds a componentDidUpdate and becomes:

var ContentEditable = React.createClass({
    render: function(){
        return <div id="contenteditable"
            onInput={this.emitChange} 
            onBlur={this.emitChange}
            contentEditable
            dangerouslySetInnerHTML={{__html: this.props.html}}></div>;
    },

    shouldComponentUpdate: function(nextProps){
        return nextProps.html !== this.getDOMNode().innerHTML;
    },

    componentDidUpdate: function() {
        if ( this.props.html !== this.getDOMNode().innerHTML ) {
           this.getDOMNode().innerHTML = this.props.html;
        }
    },

    emitChange: function(){
        var html = this.getDOMNode().innerHTML;
        if (this.props.onChange && html !== this.lastHtml) {
            this.props.onChange({
                target: {
                    value: html
                }
            });
        }
        this.lastHtml = html;
    }
});

The Virtual dom stays outdated, and it may not be the most efficient code, but at least it does work :) My bug is resolved


Details:

1) If you put shouldComponentUpdate to avoid caret jumps, then the contenteditable never rerenders (at least on keystrokes)

2) If the component never rerenders on key stroke, then React keeps an outdated virtual dom for this contenteditable.

3) If React keeps an outdated version of the contenteditable in its virtual dom tree, then if you try to reset the contenteditable to the value outdated in the virtual dom, then during the virtual dom diff, React will compute that there are no changes to apply to the DOM!

This happens mostly when:

  • you have an empty contenteditable initially (shouldComponentUpdate=true,prop="",previous vdom=N/A),
  • the user types some text and you prevent renderings (shouldComponentUpdate=false,prop=text,previous vdom="")
  • after user clicks a validation button, you want to empty that field (shouldComponentUpdate=false,prop="",previous vdom="")
  • as both the newly produced and old vdom are "", React does not touch the dom.

Get child node index

<body>
    <section>
        <section onclick="childIndex(this)">child a</section>
        <section onclick="childIndex(this)">child b</section>
        <section onclick="childIndex(this)">child c</section>
    </section>
    <script>
        function childIndex(e){
            let i = 0;
            while (e.parentNode.children[i] != e) i++;
            alert('child index '+i);
        }
    </script>
</body>

How to get an array of specific "key" in multidimensional array without looping

PHP 5.5+

Starting PHP5.5+ you have array_column() available to you, which makes all of the below obsolete.

PHP 5.3+

$ids = array_map(function ($ar) {return $ar['id'];}, $users);

Solution by @phihag will work flawlessly in PHP starting from PHP 5.3.0, if you need support before that, you will need to copy that wp_list_pluck.

PHP < 5.3

Wordpress 3.1+

In Wordpress there is a function called wp_list_pluck If you're using Wordpress that solves your problem.

PHP < 5.3

If you're not using Wordpress, since the code is open source you can copy paste the code in your project (and rename the function to something you prefer, like array_pick). View source here

How could I use requests in asyncio?

DISCLAMER: Following code creates different threads for each function.

This might be useful for some of the cases as it is simpler to use. But know that it is not async but gives illusion of async using multiple threads, even though decorator suggests that.

To make any function non blocking, simply copy the decorator and decorate any function with a callback function as parameter. The callback function will receive the data returned from the function.

import asyncio
import requests


def run_async(callback):
    def inner(func):
        def wrapper(*args, **kwargs):
            def __exec():
                out = func(*args, **kwargs)
                callback(out)
                return out

            return asyncio.get_event_loop().run_in_executor(None, __exec)

        return wrapper

    return inner


def _callback(*args):
    print(args)


# Must provide a callback function, callback func will be executed after the func completes execution !!
@run_async(_callback)
def get(url):
    return requests.get(url)


get("https://google.com")
print("Non blocking code ran !!")

How to convert HH:mm:ss.SSS to milliseconds?

If you want to use SimpleDateFormat, you could write:

private final SimpleDateFormat sdf =
    new SimpleDateFormat("yyyy-MM-dd HH:mm:ss.SSS");
    { sdf.setTimeZone(TimeZone.getTimeZone("GMT")); }

private long parseTimeToMillis(final String time) throws ParseException
    { return sdf.parse("1970-01-01 " + time).getTime(); }

But a custom method would be much more efficient. SimpleDateFormat, because of all its calendar support, time-zone support, daylight-savings-time support, and so on, is pretty slow. The slowness is worth it if you actually need some of those features, but since you don't, it might not be. (It depends how often you're calling this method, and whether efficiency is a concern for your application.)

Also, SimpleDateFormat is non-thread-safe, which is sometimes a pain. (Without knowing anything about your application, I can't guess whether that matters.)

Personally, I'd probably write a custom method.

How to change the color of header bar and address bar in newest Chrome version on Lollipop?

From the Official documentation,

For example, to set the background color to orange:

<meta name="theme-color" content="#db5945">

In addition, Chrome will show beautiful high-res favicons when they’re provided. Chrome for Android picks the highest res icon that you provide, and we recommend providing a 192×192px PNG file. For example:

<link rel="icon" sizes="192x192" href="nice-highres.png">

How to define relative paths in Visual Studio Project?

I have used a syntax like this before:

$(ProjectDir)..\headers

or

..\headers

As other have pointed out, the starting directory is the one your project file is in(vcproj or vcxproj), not where your main code is located.

Unzipping files in Python

If you want to do it in shell, instead of writing code.

 python3 -m zipfile -e myfiles.zip myfiles/

myfiles.zip is the zip archive and myfiles is the path to extract the files.

How to find children of nodes using BeautifulSoup

There's a super small section in the DOCs that shows how to find/find_all direct children.

https://www.crummy.com/software/BeautifulSoup/bs4/doc/#the-recursive-argument

In your case as you want link1 which is first direct child:

# for only first direct child
soup.find("li", { "class" : "test" }).find("a", recursive=False)

If you want all direct children:

# for all direct children
soup.find("li", { "class" : "test" }).findAll("a", recursive=False)

ActivityCompat.requestPermissions not showing dialog box

Here's an example of using requestPermissions():

First, define the permission (as you did in your post) in the manifest, otherwise, your request will automatically be denied:

<uses-permission android:name="android.permission.READ_PHONE_STATE" />

Next, define a value to handle the permission callback, in onRequestPermissionsResult():

private final int REQUEST_PERMISSION_PHONE_STATE=1;

Here's the code to call requestPermissions():

private void showPhoneStatePermission() {
    int permissionCheck = ContextCompat.checkSelfPermission(
            this, Manifest.permission.READ_PHONE_STATE);
    if (permissionCheck != PackageManager.PERMISSION_GRANTED) {
        if (ActivityCompat.shouldShowRequestPermissionRationale(this,
                Manifest.permission.READ_PHONE_STATE)) {
            showExplanation("Permission Needed", "Rationale", Manifest.permission.READ_PHONE_STATE, REQUEST_PERMISSION_PHONE_STATE);
        } else {
            requestPermission(Manifest.permission.READ_PHONE_STATE, REQUEST_PERMISSION_PHONE_STATE);
        }
    } else {
        Toast.makeText(MainActivity.this, "Permission (already) Granted!", Toast.LENGTH_SHORT).show();
    }
}

First, you check if you already have permission (remember, even after being granted permission, the user can later revoke the permission in the App Settings.)

And finally, this is how you check if you received permission or not:

@Override
public void onRequestPermissionsResult(
        int requestCode,
        String permissions[],
        int[] grantResults) {
    switch (requestCode) {
        case REQUEST_PERMISSION_PHONE_STATE:
            if (grantResults.length > 0
                    && grantResults[0] == PackageManager.PERMISSION_GRANTED) {
                Toast.makeText(MainActivity.this, "Permission Granted!", Toast.LENGTH_SHORT).show();
            } else {
                Toast.makeText(MainActivity.this, "Permission Denied!", Toast.LENGTH_SHORT).show();
            }
    }
}

private void showExplanation(String title,
                             String message,
                             final String permission,
                             final int permissionRequestCode) {
    AlertDialog.Builder builder = new AlertDialog.Builder(this);
    builder.setTitle(title)
            .setMessage(message)
            .setPositiveButton(android.R.string.ok, new DialogInterface.OnClickListener() {
                public void onClick(DialogInterface dialog, int id) {
                    requestPermission(permission, permissionRequestCode);
                }
            });
    builder.create().show();
}

private void requestPermission(String permissionName, int permissionRequestCode) {
    ActivityCompat.requestPermissions(this,
            new String[]{permissionName}, permissionRequestCode);
}

jQuery change URL of form submit

Send the data from the form:

$("#change_section_type").live "change", ->
url = $(this).attr("data-url")
postData = $(this).parents("#contract_setting_form").serializeArray()
$.ajax
  type: "PUT"
  url: url
  dataType: "script"
  data: postData

Arrays.fill with multidimensional array in Java

Arrays.fill(arr, new double[4]);

When creating a service with sc.exe how to pass in context parameters?

It also important taking in account how you access the Arguments in the code of the application.

In my c# application I used the ServiceBase class:

 class MyService : ServiceBase
{

    protected override void OnStart(string[] args)
    {
       }
 }

I registered my service using

sc create myService binpath= "MeyService.exe arg1 arg2"

But I couldn't access the arguments through the args variable when I run it as a service.

The MSDN documentation suggests not using the Main method to retrieve the binPath or ImagePath arguments. Instead it suggests placing your logic in the OnStart method and then using (C#) Environment.GetCommandLineArgs();.

To access the first arguments arg1 I need to do like this:

class MyService : ServiceBase
 {

    protected override void OnStart(string[] args)
    {

                log.Info("arg1 == "+Environment.GetCommandLineArgs()[1]);

       }
 }

this would print

       arg1 == arg1

Environment variables in Eclipse

You can also start eclipse within a shell.

You export the enronment, before calling eclipse.

Example :

#!/bin/bash
export MY_VAR="ADCA"
export PATH="/home/lala/bin;$PATH"
$ECLIPSE_HOME/eclipse -data $YOUR_WORK_SPACE_PATH

Then you can have multiple instances on eclipse with their own custome environment including workspace.

Mac OS X and multiple Java versions

New commands for installing Java via Homebrew:

  • brew cask install adoptopenjdk/openjdk/adoptopenjdk8
  • brew cask install adoptopenjdk/openjdk/adoptopenjdk11

See the homebrew-openjdk repo for the latest commands.

Installing Java

You can install Java via Homebrew, Jabba, SDKMAN or manually. See this answer for details on all the commands.

Switching Java versions*

You can switch Java versions with jenv Jabba, SDKMAN or manually. See details on all the switching commands here.

Best solutions

  • Jabba is designed to work on multiple platforms, so it's a good option if you want a solution that'll also work on Windows
  • Using Homebrew to download Java versions and jenv to switch versions provides a nice workflow. jenv makes it easy to work with Java versions stored in any directory on your machine, so it's a good alternative if you're interested in storing Java in non-default directories.
  • Using SDKMAN to download Javas and switch versions is another great alternative
  • Manually switching should be avoided because it's an unnecessary headache.

Function to manually switch Java versions

Here's the Bash / ZSH function for manually switching Java versions (by OpenJDK):

jdk() {
        version=$1
        export JAVA_HOME=$(/usr/libexec/java_home -v"$version");
        java -version
 }

There are great tools for switching Java versions, so I highly recommend against doing it manually.

How To Add An "a href" Link To A "div"?

Your solutions don't seem to be working for me, I have the following code. How to put link into the last two divs.

<html xmlns="http://www.w3.org/1999/xhtml" xmlns:v="urn:schemas-microsoft-com:vml" xmlns:o="urn:schemas-microsoft-com:office:office">

<style>
/* Import */
@import url(https://fonts.googleapis.com/css?family=Quicksand:300,400);
* {
  font-family: "Quicksand", sans-serif; 
  font-weight: bold; 
  text-align: center;  
  text-transform: uppercase; 
  -webkit-transition: all 0.25s ease; 
  -moz-transition: all 0.25s ease; 
  -ms-transition: all 0.25s ease; 
  -o-transition: all 0.025s ease; 
}

/* Colors */

#ora {
  background-color: #e67e22; 
}

#red {
  background-color: #e74c3c; 
}

#orab {
  background-color: white; 
  border: 5px solid #e67e22; 
}

#redb {
  background-color: white; 
  border: 5px solid #e74c3c; 
}
/* End of Colors */

.B {
  width: 240px; 
  height: 55px; 
  margin: auto; 
  line-height: 45px; 
  display: inline-block; 
  box-sizing: border-box; 
  -webkit-box-sizing: border-box; 
  -moz-box-sizing: border-box; 
  -ms-box-sizing: border-box; 
  -o-box-sizing: border-box; 
} 

#orab:hover {
  background-color: #e67e22; 
}

#redb:hover {
  background-color: #e74c3c; 
}
#whib:hover {
  background-color: #ecf0f1; 
}

/* End of Border

.invert:hover {
  -webkit-filter: invert(1);
  -moz-filter: invert(1);
  -ms-filter: invert(1);
  -o-filter: invert(1);
}
</style>
<h1>Flat and Modern Buttons</h1>
<h2>Border Stylin'</h2> 

<div class="B bo" id="orab">See the movies list</div></a>
<div class="B bo" id="redb">Avail a free rental day</div>

</html>

What does axis in pandas mean?

Let's visualize (you gonna remember always), enter image description here

In Pandas:

  1. axis=0 means along "indexes". It's a row-wise operation.

Suppose, to perform concat() operation on dataframe1 & dataframe2, we will take dataframe1 & take out 1st row from dataframe1 and place into the new DF, then we take out another row from dataframe1 and put into new DF, we repeat this process until we reach to the bottom of dataframe1. Then, we do the same process for dataframe2.

Basically, stacking dataframe2 on top of dataframe1 or vice a versa.

E.g making a pile of books on a table or floor

  1. axis=1 means along "columns". It's a column-wise operation.

Suppose, to perform concat() operation on dataframe1 & dataframe2, we will take out the 1st complete column(a.k.a 1st series) of dataframe1 and place into new DF, then we take out the second column of dataframe1 and keep adjacent to it (sideways), we have to repeat this operation until all columns are finished. Then, we repeat the same process on dataframe2. Basically, stacking dataframe2 sideways.

E.g arranging books on a bookshelf.

More to it, since arrays are better representations to represent a nested n-dimensional structure compared to matrices! so below can help you more to visualize how axis plays an important role when you generalize to more than one dimension. Also, you can actually print/write/draw/visualize any n-dim array but, writing or visualizing the same in a matrix representation(3-dim) is impossible on a paper more than 3-dimensions.

enter image description here

TypeError: Cannot read property 'then' of undefined

TypeError: Cannot read property 'then' of undefined when calling a Django service using AngularJS.

If you are calling a Python service, the code will look like below:

this.updateTalentSupplier=function(supplierObj){
  var promise = $http({
    method: 'POST',
      url: bbConfig.BWS+'updateTalentSupplier/',
      data:supplierObj,
      withCredentials: false,
      contentType:'application/json',
      dataType:'json'
    });
    return promise; //Promise is returned 
}

We are using MongoDB as the database(I know it doesn't matter. But if someone is searching with MongoDB + Python (Django) + AngularJS the result should come.

Using any() and all() to check if a list contains one set of values or another

Generally speaking:

all and any are functions that take some iterable and return True, if

  • in the case of all(), no values in the iterable are falsy;
  • in the case of any(), at least one value is truthy.

A value x is falsy iff bool(x) == False. A value x is truthy iff bool(x) == True.

Any non-booleans in the iterable will be fine — bool(x) will coerce any x according to these rules: 0, 0.0, None, [], (), [], set(), and other empty collections will yield False, anything else True. The docstring for bool uses the terms 'true'/'false' for 'truthy'/'falsy', and True/False for the concrete boolean values.


In your specific code samples:

You misunderstood a little bit how these functions work. Hence, the following does something completely not what you thought:

if any(foobars) == big_foobar:

...because any(foobars) would first be evaluated to either True or False, and then that boolean value would be compared to big_foobar, which generally always gives you False (unless big_foobar coincidentally happened to be the same boolean value).

Note: the iterable can be a list, but it can also be a generator/generator expression (˜ lazily evaluated/generated list) or any other iterator.

What you want instead is:

if any(x == big_foobar for x in foobars):

which basically first constructs an iterable that yields a sequence of booleans—for each item in foobars, it compares the item to big_foobar and emits the resulting boolean into the resulting sequence:

tmp = (x == big_foobar for x in foobars)

then any walks over all items in tmp and returns True as soon as it finds the first truthy element. It's as if you did the following:

In [1]: foobars = ['big', 'small', 'medium', 'nice', 'ugly']                                        

In [2]: big_foobar = 'big'                                                                          

In [3]: any(['big' == big_foobar, 'small' == big_foobar, 'medium' == big_foobar, 'nice' == big_foobar, 'ugly' == big_foobar])        
Out[3]: True

Note: As DSM pointed out, any(x == y for x in xs) is equivalent to y in xs but the latter is more readable, quicker to write and runs faster.

Some examples:

In [1]: any(x > 5 for x in range(4))
Out[1]: False

In [2]: all(isinstance(x, int) for x in range(10))
Out[2]: True

In [3]: any(x == 'Erik' for x in ['Erik', 'John', 'Jane', 'Jim'])
Out[3]: True

In [4]: all([True, True, True, False, True])
Out[4]: False

See also: http://docs.python.org/2/library/functions.html#all

How to highlight cell if value duplicate in same column for google spreadsheet?

Highlight duplicates (in column C):

=COUNTIF(C:C, C1) > 1

Explanation: The C1 here doesn't refer to the first row in C. Because this formula is evaluated by a conditional format rule, instead, when the formula is checked to see if it applies, the C1 effectively refers to whichever row is currently being evaluated to see if the highlight should be applied. (So it's more like INDIRECT(C &ROW()), if that means anything to you!). Essentially, when evaluating a conditional format formula, anything which refers to row 1 is evaluated against the row that the formula is being run against. (And yes, if you use C2 then you asking the rule to check the status of the row immediately below the one currently being evaluated.)

So this says, count up occurences of whatever is in C1 (the current cell being evaluated) that are in the whole of column C and if there is more than 1 of them (i.e. the value has duplicates) then: apply the highlight (because the formula, overall, evaluates to TRUE).

Highlight the first duplicate only:

=AND(COUNTIF(C:C, C1) > 1, COUNTIF(C$1:C1, C1) = 1)

Explanation: This only highlights if both of the COUNTIFs are TRUE (they appear inside an AND()).

The first term to be evaluated (the COUNTIF(C:C, C1) > 1) is the exact same as in the first example; it's TRUE only if whatever is in C1 has a duplicate. (Remember that C1 effectively refers to the current row being checked to see if it should be highlighted).

The second term (COUNTIF(C$1:C1, C1) = 1) looks similar but it has three crucial differences:

It doesn't search the whole of column C (like the first one does: C:C) but instead it starts the search from the first row: C$1 (the $ forces it to look literally at row 1, not at whichever row is being evaluated).

And then it stops the search at the current row being evaluated C1.

Finally it says = 1.

So, it will only be TRUE if there are no duplicates above the row currently being evaluated (meaning it must be the first of the duplicates).

Combined with that first term (which will only be TRUE if this row has duplicates) this means only the first occurrence will be highlighted.

Highlight the second and onwards duplicates:

=AND(COUNTIF(C:C, C1) > 1, NOT(COUNTIF(C$1:C1, C1) = 1), COUNTIF(C1:C, C1) >= 1)

Explanation: The first expression is the same as always (TRUE if the currently evaluated row is a duplicate at all).

The second term is exactly the same as the last one except it's negated: It has a NOT() around it. So it ignores the first occurence.

Finally the third term picks up duplicates 2, 3 etc. COUNTIF(C1:C, C1) >= 1 starts the search range at the currently evaluated row (the C1 in the C1:C). Then it only evaluates to TRUE (apply highlight) if there is one or more duplicates below this one (and including this one): >= 1 (it must be >= not just > otherwise the last duplicate is ignored).

How to execute an Oracle stored procedure via a database link

for me, this worked

exec utl_mail.send@myotherdb(
  sender => '[email protected]',recipients => '[email protected], 
  cc => null, subject => 'my subject', message => 'my message'
); 

How to make Java Set?

Like this:

import java.util.*;
Set<Integer> a = new HashSet<Integer>();
a.add( 1);
a.add( 2);
a.add( 3);

Or adding from an Array/ or multiple literals; wrap to a list, first.

Integer[] array = new Integer[]{ 1, 4, 5};
Set<Integer> b = new HashSet<Integer>();
b.addAll( Arrays.asList( b));         // from an array variable
b.addAll( Arrays.asList( 8, 9, 10));  // from literals

To get the intersection:

// copies all from A;  then removes those not in B.
Set<Integer> r = new HashSet( a);
r.retainAll( b);
// and print;   r.toString() implied.
System.out.println("A intersect B="+r);

Hope this answer helps. Vote for it!

How do you specify a byte literal in Java?

What about overriding the method with

void f(int value)
{
  f((byte)value);
}

this will allow for f(0)

Why is my asynchronous function returning Promise { <pending> } instead of a value?

I know this question was asked 2 years ago, but I run into the same issue and the answer for the problem is since ES2017, that you can simply await the functions return value (as of now, only works in async functions), like:

let AuthUser = function(data) {
  return google.login(data.username, data.password).then(token => { return token } )
}

let userToken = await AuthUser(data)
console.log(userToken) // your data

How to convert a single char into an int

The answers provided are great as long as you only want to handle Arabic numerals, and are working in an encoding where those numerals are sequential, and in the same place as ASCII.

This is almost always the case.

If it isn't then you need a proper library to help you.

Let's start with ICU.

  1. First convert the byte-string to a unicode string. (Left as an exercise for the reader).
  2. Then use uchar.h to look at each character.
  3. if we the character is UBool u_isdigit (UChar32 c)
  4. then the value is int32_t u_charDigitValue ( UChar32 c )

Or maybe ICU has some function to do it for you - I haven't looked at it in detail.

Add MIME mapping in web.config for IIS Express

I was having a problem getting my ASP.NET 5.0/MVC 6 app to serve static binary file types or browse virtual directories. It looks like this is now done in Configure() at startup. See http://docs.asp.net/en/latest/fundamentals/static-files.html for a quick primer.

Reset C int array to zero : the fastest way?

Here's the function I use:

template<typename T>
static void setValue(T arr[], size_t length, const T& val)
{
    std::fill(arr, arr + length, val);
}

template<typename T, size_t N>
static void setValue(T (&arr)[N], const T& val)
{
    std::fill(arr, arr + N, val);
}

You can call it like this:

//fixed arrays
int a[10];
setValue(a, 0);

//dynamic arrays
int *d = new int[length];
setValue(d, length, 0);

Above is more C++11 way than using memset. Also you get compile time error if you use dynamic array with specifying the size.

JSON order mixed up

Real answer can be found in specification, json is unordered. However as a human reader I ordered my elements in order of importance. Not only is it a more logic way, it happened to be easier to read. Maybe the author of the specification never had to read JSON, I do.. So, Here comes a fix:

/**
 * I got really tired of JSON rearranging added properties.
 * Specification states:
 * "An object is an unordered set of name/value pairs"
 * StackOverflow states:
 * As a consequence, JSON libraries are free to rearrange the order of the elements as they see fit.
 * I state:
 * My implementation will freely arrange added properties, IN SEQUENCE ORDER!
 * Why did I do it? Cause of readability of created JSON document!
 */
private static class OrderedJSONObjectFactory {
    private static Logger log = Logger.getLogger(OrderedJSONObjectFactory.class.getName());
    private static boolean setupDone = false;
    private static Field JSONObjectMapField = null;

    private static void setupFieldAccessor() {
        if( !setupDone ) {
            setupDone = true;
            try {
                JSONObjectMapField = JSONObject.class.getDeclaredField("map");
                JSONObjectMapField.setAccessible(true);
            } catch (NoSuchFieldException ignored) {
                log.warning("JSONObject implementation has changed, returning unmodified instance");
            }
        }
    }

    private static JSONObject create() {
        setupFieldAccessor();
        JSONObject result = new JSONObject();
        try {
            if (JSONObjectMapField != null) {
                JSONObjectMapField.set(result, new LinkedHashMap<>());
            }
        }catch (IllegalAccessException ignored) {}
        return result;
    }
}

How to open up a form from another form in VB.NET?

You can also use showdialog

Private Sub Button3_Click(sender As System.Object, e As System.EventArgs) _
                      Handles Button3.Click

     dim mydialogbox as new aboutbox1
     aboutbox1.showdialog()

End Sub

Cannot connect to local SQL Server with Management Studio

Try to see, if the service "SQL Server (MSSQLSERVER)" it's started, this solved my problem.

How to custom switch button?

However, I might not be taking the best approach, but this is how I have created some Switch like UIs in few of my apps. Here is the code -

<RadioGroup
        android:checkedButton="@+id/offer"
        android:id="@+id/toggle"
        android:layout_width="match_parent"
        android:layout_height="30dp"
        android:layout_marginBottom="@dimen/margin_medium"
        android:layout_marginLeft="50dp"
        android:layout_marginRight="50dp"
        android:layout_marginTop="@dimen/margin_medium"
        android:background="@drawable/pink_out_line"
        android:orientation="horizontal">

        <RadioButton
            android:layout_marginTop="1dp"
            android:layout_marginBottom="1dp"
            android:layout_marginLeft="1dp"
            android:id="@+id/search"
            android:background="@drawable/toggle_widget_background"
            android:layout_width="0dp"
            android:layout_height="match_parent"
            android:layout_weight="1"
            android:button="@null"
            android:gravity="center"
            android:text="Search"
            android:textColor="@color/white" />

        <RadioButton
            android:layout_marginRight="1dp"
            android:layout_marginTop="1dp"
            android:layout_marginBottom="1dp"
            android:id="@+id/offer"
            android:layout_width="0dp"
            android:layout_height="match_parent"
            android:layout_weight="1"
            android:background="@drawable/toggle_widget_background"
            android:button="@null"
            android:gravity="center"
            android:text="Offers"
            android:textColor="@color/white" />
    </RadioGroup>

pink_out_line.xml

<shape xmlns:android="http://schemas.android.com/apk/res/android"
    android:shape="rectangle">
    <corners android:radius="2dp" />
    <solid android:color="#80000000" />
    <stroke
        android:width="1dp"
        android:color="@color/pink" />
</shape>

toggle_widget_background.xml

<?xml version="1.0" encoding="UTF-8" standalone="no"?>
<selector xmlns:android="http://schemas.android.com/apk/res/android">
    <item android:drawable="@color/pink" android:state_checked="true" />
    <item android:drawable="@color/dark_pink" android:state_pressed="true" />
    <item android:drawable="@color/transparent" />
</selector>

And here is the output -enter image description here

Android Device not recognized by adb

I recently had this issue (but before that debug over wifi was working fine) and since none of the above answers helped me let me share what I did.

  1. Go to developer options
  2. Find Select USB configurations and click it
  3. Choose MTP (Media Transfer Protocol)

Note: If it's set to this option chose another option such as PTP first then set it to MTP again.

UPDATE:

PTP stands for “Picture Transfer Protocol.” When Android uses this protocol, it appears to the computer as a digital camera.

MTP is actually based on PTP, but adds more features, or “extensions.” PTP works similarly to MTP and is commonly used by digital cameras.

How to pass a value from Vue data to href?

Or you can do that with ES6 template literal:

<a :href="`/job/${r.id}`"

Set opacity of background image without affecting child elements

To really fine-tune things, I recommend placing the appropriate selections in browser-targeting wrappers. This was the only thing that worked for me when I could not get IE7 and IE8 to "play nicely with others" (as I am currently working for a software company who continues to support them).

/* color or background image for all browsers, of course */            
#myBackground {
    background-color:#666; 
}
/* target chrome & safari without disrupting IE7-8 */
@media screen and (-webkit-min-device-pixel-ratio:0) {
    #myBackground {
        -khtml-opacity:.50; 
        opacity:.50;
    }
}
/* target firefox without disrupting IE */
@-moz-document url-prefix() {
    #myBackground {
        -moz-opacity:.50;
        opacity:0.5;
    }
}
/* and IE last so it doesn't blow up */
#myBackground {
    opacity:.50;
    filter:alpha(opacity=50);
    filter: progid:DXImageTransform.Microsoft.Alpha(opacity=0.5);
}

I may have redundancies in the above code -- if anyone wishes to clean it up further, feel free!

trim left characters in sql server?

use "LEFT"

 select left('Hello World', 5)

or use "SUBSTRING"

 select substring('Hello World', 1, 5)

How to clear an ImageView in Android?

I tried this for to clear Image and DrawableCache in ImageView

ImgView.setImageBitmap(null);
ImgView.destroyDrawingCache();

I hope this works for you !

In JPA 2, using a CriteriaQuery, how to count results

With Spring Data Jpa, we can use this method:

    /*
     * (non-Javadoc)
     * @see org.springframework.data.jpa.repository.JpaSpecificationExecutor#count(org.springframework.data.jpa.domain.Specification)
     */
    @Override
    public long count(@Nullable Specification<T> spec) {
        return executeCountQuery(getCountQuery(spec, getDomainClass()));
    }

Service Temporarily Unavailable Magento?

If you run into this problem (like I did) and NO maintenance.flag file exists anywhere, it's the Redis cache that's causing the problem; clear it.

I had to clear the Redis cache by contacting my hosting company and let them do it because I don't have access to that cache.

I figured this out using this answer: https://magento.stackexchange.com/a/55814/77803

How to define and use function inside Jenkins Pipeline config?

Solved! The call build job: project, parameters: params fails with an error java.lang.UnsupportedOperationException: must specify $class with an implementation of interface java.util.List when params = [:]. Replacing it with params = null solved the issue. Here the working code below.

def doCopyMibArtefactsHere(projectName) {
    step ([
        $class: 'CopyArtifact',
        projectName: projectName,
        filter: '**/**.mib',
        fingerprintArtifacts: true, 
        flatten: true
    ]);
}

def BuildAndCopyMibsHere(projectName, params = null) {
    build job: project, parameters: params
    doCopyMibArtefactsHere(projectName)
}
node { 
    stage('Prepare Mib'){
        BuildAndCopyMibsHere('project1')
    }
}

How can I "reset" an Arduino board?

Here's what I did in Linux to be able to program my Arduino Micro which was stuck in a loop sending the 0 key when connected by USB;

# while true; do xinput float $(xinput --list | grep -i Arduino | awk '{print $7}' | cut -d'=' -f 2); done

Your output might be slightly different so just try running;

# watch xinput --list

then plug in the Arduino and see how the output is formatted.

This stopped X from accepting the keypresses and allowed the Arduino IDE to program finally!

change type of input field with jQuery

One step solution

$('#password').get(0).type = 'text';

Replace words in the body text

Try to apply the above suggested solution on pretty big document, replacing pretty short strings which might be present in innerHTML or even innerText, and your html design becomes broken at best

Therefore I firstly pickup only text node elements via HTML DOM nodes, like this

function textNodesUnder(node){
  var all = [];
  for (node=node.firstChild;node;node=node.nextSibling){
    if (node.nodeType==3) all.push(node);
    else all = all.concat(textNodesUnder(node));
  }
  return all;
}

textNodes=textNodesUnder(document.body)
for (i in textNodes) { textNodes[i].nodeValue = textNodes[i].nodeValue.replace(/hello/g, 'hi');    

`and followingly I applied the replacement on all of them in cycle

How to find out what character key is pressed?

"Clear" JavaScript:

_x000D_
_x000D_
function myKeyPress(e){
  var keynum;

  if(window.event) { // IE                  
    keynum = e.keyCode;
  } else if(e.which){ // Netscape/Firefox/Opera                 
    keynum = e.which;
  }

  alert(String.fromCharCode(keynum));
}
_x000D_
<input type="text" onkeypress="return myKeyPress(event)" />
_x000D_
_x000D_
_x000D_

JQuery:

_x000D_
_x000D_
$("input").keypress(function(event){
  alert(String.fromCharCode(event.which)); 
});
_x000D_
<script src="https://cdnjs.cloudflare.com/ajax/libs/jquery/3.3.1/jquery.min.js"></script>
<input/>
_x000D_
_x000D_
_x000D_

lexers vs parsers

To answer the question as asked (without repeating unduly what appears in other answers)

Lexers and parsers are not very different, as suggested by the accepted answer. Both are based on simple language formalisms: regular languages for lexers and, almost always, context-free (CF) languages for parsers. They both are associated with fairly simple computational models, the finite state automaton and the push-down stack automaton. Regular languages are a special case of context-free languages, so that lexers could be produced with the somewhat more complex CF technology. But it is not a good idea for at least two reasons.

A fundamental point in programming is that a system component should be buit with the most appropriate technology, so that it is easy to produce, to understand and to maintain. The technology should not be overkill (using techniques much more complex and costly than needed), nor should it be at the limit of its power, thus requiring technical contortions to achieve the desired goal.

That is why "It seems fashionable to hate regular expressions". Though they can do a lot, they sometimes require very unreadable coding to achieve it, not to mention the fact that various extensions and restrictions in implementation somewhat reduce their theoretical simplicity. Lexers do not usually do that, and are usually a simple, efficient, and appropriate technology to parse token. Using CF parsers for token would be overkill, though it is possible.

Another reason not to use CF formalism for lexers is that it might then be tempting to use the full CF power. But that might raise sructural problems regarding the reading of programs.

Fundamentally, most of the structure of program text, from which meaning is extracted, is a tree structure. It expresses how the parse sentence (program) is generated from syntax rules. Semantics is derived by compositional techniques (homomorphism for the mathematically oriented) from the way syntax rules are composed to build the parse tree. Hence the tree structure is essential. The fact that tokens are identified with a regular set based lexer does not change the situation, because CF composed with regular still gives CF (I am speaking very loosely about regular transducers, that transform a stream of characters into a stream of token).

However, CF composed with CF (via CF transducers ... sorry for the math), does not necessarily give CF, and might makes things more general, but less tractable in practice. So CF is not the appropriate tool for lexers, even though it can be used.

One of the major differences between regular and CF is that regular languages (and transducers) compose very well with almost any formalism in various ways, while CF languages (and transducers) do not, not even with themselves (with a few exceptions).

(Note that regular transducers may have others uses, such as formalization of some syntax error handling techniques.)

BNF is just a specific syntax for presenting CF grammars.

EBNF is a syntactic sugar for BNF, using the facilities of regular notation to give terser version of BNF grammars. It can always be transformed into an equivalent pure BNF.

However, the regular notation is often used in EBNF only to emphasize these parts of the syntax that correspond to the structure of lexical elements, and should be recognized with the lexer, while the rest with be rather presented in straight BNF. But it is not an absolute rule.

To summarize, the simpler structure of token is better analyzed with the simpler technology of regular languages, while the tree oriented structure of the language (of program syntax) is better handled by CF grammars.

I would suggest also looking at AHR's answer.

But this leaves a question open: Why trees?

Trees are a good basis for specifying syntax because

  • they give a simple structure to the text

  • there are very convenient for associating semantics with the text on the basis of that structure, with a mathematically well understood technology (compositionality via homomorphisms), as indicated above. It is a fundamental algebraic tool to define the semantics of mathematical formalisms.

Hence it is a good intermediate representation, as shown by the success of Abstract Syntax Trees (AST). Note that AST are often different from parse tree because the parsing technology used by many professionals (Such as LL or LR) applies only to a subset of CF grammars, thus forcing grammatical distorsions which are later corrected in AST. This can be avoided with more general parsing technology (based on dynamic programming) that accepts any CF grammar.

Statement about the fact that programming languages are context-sensitive (CS) rather than CF are arbitrary and disputable.

The problem is that the separation of syntax and semantics is arbitrary. Checking declarations or type agreement may be seen as either part of syntax, or part of semantics. The same would be true of gender and number agreement in natural languages. But there are natural languages where plural agreement depends on the actual semantic meaning of words, so that it does not fit well with syntax.

Many definitions of programming languages in denotational semantics place declarations and type checking in the semantics. So stating as done by Ira Baxter that CF parsers are being hacked to get a context sensitivity required by syntax is at best an arbitrary view of the situation. It may be organized as a hack in some compilers, but it does not have to be.

Also it is not just that CS parsers (in the sense used in other answers here) are hard to build, and less efficient. They are are also inadequate to express perspicuously the kinf of context-sensitivity that might be needed. And they do not naturally produce a syntactic structure (such as parse-trees) that is convenient to derive the semantics of the program, i.e. to generate the compiled code.

Page redirect with successful Ajax request

Another option is:

window.location.replace("your_url")

Can I compile all .cpp files in src/ to .o's in obj/, then link to binary in ./?

Makefile part of the question

This is pretty easy, unless you don't need to generalize try something like the code below (but replace space indentation with tabs near g++)

SRC_DIR := .../src
OBJ_DIR := .../obj
SRC_FILES := $(wildcard $(SRC_DIR)/*.cpp)
OBJ_FILES := $(patsubst $(SRC_DIR)/%.cpp,$(OBJ_DIR)/%.o,$(SRC_FILES))
LDFLAGS := ...
CPPFLAGS := ...
CXXFLAGS := ...

main.exe: $(OBJ_FILES)
   g++ $(LDFLAGS) -o $@ $^

$(OBJ_DIR)/%.o: $(SRC_DIR)/%.cpp
   g++ $(CPPFLAGS) $(CXXFLAGS) -c -o $@ $<

Automatic dependency graph generation

A "must" feature for most make systems. With GCC in can be done in a single pass as a side effect of the compilation by adding -MMD flag to CXXFLAGS and -include $(OBJ_FILES:.o=.d) to the end of the makefile body:

CXXFLAGS += -MMD
-include $(OBJ_FILES:.o=.d)

And as guys mentioned already, always have GNU Make Manual around, it is very helpful.

Using lodash to compare jagged arrays (items existence without order)

PURE JS (works also when arrays and subarrays has more than 2 elements with arbitrary order). If strings contains , use as join('-') parametr character (can be utf) which is not used in strings

array1.map(x=>x.sort()).sort().join() === array2.map(x=>x.sort()).sort().join()

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_x000D_
var array1 = [['a', 'b'], ['b', 'c']];_x000D_
var array2 = [['b', 'c'], ['b', 'a']];_x000D_
_x000D_
var r = array1.map(x=>x.sort()).sort().join() === array2.map(x=>x.sort()).sort().join();_x000D_
_x000D_
console.log(r);
_x000D_
_x000D_
_x000D_

How to completely remove a dialog on close

This is worked for me

$('<div>We failed</div>')
    .dialog(
    {
        title: 'Error',
        close: function(event, ui)
        {
            $(this).dialog("close");
            $(this).remove();
        }
    });

Cheers!

PS: I had a somewhat similar problem and the above approach solved it.

How to use CSS to surround a number with a circle?

HTML EXAMPLE

<h3><span class="numberCircle">1</span> Regiones del Interior</h3>

CODE

    .numberCircle { 

    border-radius:50%;
    width:40px;
    height:40px;
    display:block;
    float:left;
    border:2px solid #000000;
    color:#000000;
    text-align:center;
    margin-right:5px;

}

Set height of chart in Chart.js

Needed the chart to fill the parent element 100%, rather than setting height manually, and the problem was to force parent div to always fill remaining space.

After setting responsive and ratio options (check out related chartjs doc), the following css did the trick:

html

<div class="panel">
  <div class="chart-container">
    <canvas id="chart"></canvas>
  </div>
</div>

scss:

.panel {
  display: flex;

  .chart-container {
    position: relative;
    flex-grow: 1;
    min-height: 0;
  }
}

Python dictionary replace values

If you iterate over a dictionary you get the keys, so assuming your dictionary is in a variable called data and you have some function find_definition() which gets the definition, you can do something like the following:

for word in data:
    data[word] = find_definition(word)

Submitting HTML form using Jquery AJAX

Quick Description of AJAX

AJAX is simply Asyncronous JSON or XML (in most newer situations JSON). Because we are doing an ASYNC task we will likely be providing our users with a more enjoyable UI experience. In this specific case we are doing a FORM submission using AJAX.

Really quickly there are 4 general web actions GET, POST, PUT, and DELETE; these directly correspond with SELECT/Retreiving DATA, INSERTING DATA, UPDATING/UPSERTING DATA, and DELETING DATA. A default HTML/ASP.Net webform/PHP/Python or any other form action is to "submit" which is a POST action. Because of this the below will all describe doing a POST. Sometimes however with http you might want a different action and would likely want to utilitize .ajax.

My code specifically for you (described in code comments):

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_x000D_
/* attach a submit handler to the form */
$("#formoid").submit(function(event) {

  /* stop form from submitting normally */
  event.preventDefault();

  /* get the action attribute from the <form action=""> element */
  var $form = $(this),
    url = $form.attr('action');

  /* Send the data using post with element id name and name2*/
  var posting = $.post(url, {
    name: $('#name').val(),
    name2: $('#name2').val()
  });

  /* Alerts the results */
  posting.done(function(data) {
    $('#result').text('success');
  });
  posting.fail(function() {
    $('#result').text('failed');
  });
});
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<script src="https://cdnjs.cloudflare.com/ajax/libs/jquery/3.3.1/jquery.min.js"></script>

<form id="formoid" action="studentFormInsert.php" title="" method="post">
  <div>
    <label class="title">First Name</label>
    <input type="text" id="name" name="name">
  </div>
  <div>
    <label class="title">Last Name</label>
    <input type="text" id="name2" name="name2">
  </div>
  <div>
    <input type="submit" id="submitButton" name="submitButton" value="Submit">
  </div>
</form>

<div id="result"></div>
_x000D_
_x000D_
_x000D_


Documentation

From jQuery website $.post documentation.

Example: Send form data using ajax requests

$.post("test.php", $("#testform").serialize());

Example: Post a form using ajax and put results in a div

<!DOCTYPE html>
<html>
    <head>
        <script src="http://code.jquery.com/jquery-1.9.1.js"></script>
    </head>
    <body>
        <form action="/" id="searchForm">
            <input type="text" name="s" placeholder="Search..." />
            <input type="submit" value="Search" />
        </form>
        <!-- the result of the search will be rendered inside this div -->
        <div id="result"></div>
        <script>
            /* attach a submit handler to the form */
            $("#searchForm").submit(function(event) {

                /* stop form from submitting normally */
                event.preventDefault();

                /* get some values from elements on the page: */
                var $form = $(this),
                    term = $form.find('input[name="s"]').val(),
                    url = $form.attr('action');

                /* Send the data using post */
                var posting = $.post(url, {
                    s: term
                });

                /* Put the results in a div */
                posting.done(function(data) {
                    var content = $(data).find('#content');
                    $("#result").empty().append(content);
                });
            });
        </script>
    </body>
</html>

Important Note

Without using OAuth or at minimum HTTPS (TLS/SSL) please don't use this method for secure data (credit card numbers, SSN, anything that is PCI, HIPAA, or login related)

Does MS SQL Server's "between" include the range boundaries?

It does includes boundaries.

declare @startDate date = cast('15-NOV-2016' as date) 
declare @endDate date = cast('30-NOV-2016' as date)
create table #test (c1 date)
insert into #test values(cast('15-NOV-2016' as date))
insert into #test values(cast('20-NOV-2016' as date))
insert into #test values(cast('30-NOV-2016' as date))
select * from #test where c1 between @startDate and @endDate
drop table #test
RESULT    c1
2016-11-15
2016-11-20
2016-11-30


declare @r1 int  = 10
declare @r2 int  = 15
create table #test1 (c1 int)
insert into #test1 values(10)
insert into #test1 values(15)
insert into #test1 values(11)
select * from #test1 where c1 between @r1 and @r2
drop table #test1
RESULT c1
10
11
15

TypeError: $.ajax(...) is not a function?

If you are using bootstrap html template remember to remove the link to jquery slim at the bottom of the template. I post this detail here as I cannot comment answers yet..

Can (domain name) subdomains have an underscore "_" in it?

Clarifying bortzmeyer and David Tonhofer, domain name and subdomain name labels can contain leading underscores, but nowhere else.

As David Tonhofer wrote, labels are the in-between-the-periods parts and should follow the LDH rule except when specifying service labels and port labels to differentiate them from regular labels. Then they must occur at the beginning of the label which should be the "Short Names" from the Service Name and Port Number Registry, the port number with no leading 0s, or the protocol (ie. tcp, udp). These service labels are further limited to 15 characters.

  • RFC2782 specifies prefixing service record subdomains with underscores.
  • RFC6698 specifies prefixing port numbers with underscores in TLSA certificate records.

Contrary to David Tonhofer's answer, IDN does not allows for encoding underscore ('_' U+005F LOW LINE) or any other invalid ASCII character.

From RFC5890

[..] two new subsets of LDH labels are created by the introduction of IDNA. These are called Reserved LDH labels (R-LDH labels) and Non-Reserved LDH labels (NR-LDH labels). Reserved LDH labels, known as "tagged domain names" in some other contexts, have the property that they contain "--" in the third and fourth characters but which otherwise conform to LDH label rules.

Punycode encodes all ASCII codepoints as ASCII directly, including underscore. The resulting R-LDH would not conform the the LDH label rules. For example, S_.com would be encoded as xn--_-zmb.com which violates the rules. There may be a homographic codepoint which looks like an underscore that can be coded legally (perhaps '_' U+FF3F fullwidth low line), but these kinds of codepoints would be categorized as DISALLOWED by RFC5892 under 2.3 IgnorableProperties as a Noncharacter_Code_Point.

RACE (the other proposed IDN encoding scheme) was not accepted as a standard by IETF and should not be used.

500 Internal Server Error for php file not for html

Google guides me here but it didn't fix mine, this is a very general question and there are various causes, so I post my problem and solution here for reference in case anyone might read this later.

Another possible cause of 500 error is syntax error in header(...) function, like this one:

header($_SERVER['SERVER_PROTOCOL'] . '200 OK');

Be aware there should be space between server protocol and status code, so it should be:

header($_SERVER['SERVER_PROTOCOL'] . ' 200 OK');

So I suggest check your http header call if you have it in your code.

List comprehension vs. lambda + filter

Although filter may be the "faster way", the "Pythonic way" would be not to care about such things unless performance is absolutely critical (in which case you wouldn't be using Python!).

Bootstrap 3: Keep selected tab on page refresh

This one use HTML5 localStorage to store active tab

$('a[data-toggle="tab"]').on('shown.bs.tab', function(e) {
    localStorage.setItem('activeTab', $(e.target).attr('href'));
});
var activeTab = localStorage.getItem('activeTab');
if (activeTab) {
   $('#navtab-container a[href="' + activeTab + '"]').tab('show');
}

ref: http://www.tutorialrepublic.com/faq/how-to-keep-the-current-tab-active-on-page-reload-in-bootstrap.php https://www.w3schools.com/bootstrap/bootstrap_ref_js_tab.asp

How to write URLs in Latex?

You just need to escape characters that have special meaning: # $ % & ~ _ ^ \ { }

So

http://stack_overflow.com/~foo%20bar#link

would be

http://stack\_overflow.com/\~foo\%20bar\#link

How to enter special characters like "&" in oracle database?

Justin's answer is the way to go, but also as an FYI you can use the chr() function with the ascii value of the character you want to insert. For this example it would be:

INSERT INTO STUDENT(name, class_id) VALUES ('Samantha', 'Java_22 '||chr(38)||' Oracle_14'); 

Failed to resolve: com.android.support:appcompat-v7:26.0.0

My issue got resolved with the help of following steps:

For gradle 3.0.0 and above version

  1. add google() below jcenter()
  2. Change the compileSdkVersion to 26 and buildToolsVersion to 26.0.2
  3. Change to gradle-4.2.1-all.zip in the gradle_wrapper.properties file

vertical align middle in <div>

This Code Is for Vertical Middle and Horizontal Center Align without specify fixed height:

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_x000D_
.parent-class-name {_x000D_
  position: relative;_x000D_
}_x000D_
_x000D_
.className {_x000D_
  position: absolute;_x000D_
  top: 50%;_x000D_
  left: 0;_x000D_
  right: 0;_x000D_
  margin: 0 auto;_x000D_
  transform: translateY(-50%);_x000D_
  -moz-transform: translateY(-50%);_x000D_
  -webkit-transform: translateY(-50%);_x000D_
}
_x000D_
_x000D_
_x000D_

Babel 6 regeneratorRuntime is not defined

babel-regenerator-runtime is now deprecated, instead one should use regenerator-runtime.

To use the runtime generator with webpack and babel v7:

install regenerator-runtime:

npm i -D regenerator-runtime

And then add within webpack configuration :

entry: [
  'regenerator-runtime/runtime',
  YOUR_APP_ENTRY
]

Change select box option background color

If you really want to style the within a , consider switching to a Javascript/CSS based drop down such as http://getbootstrap.com/2.3.2/components.html#dropdowns or https://silviomoreto.github.io/bootstrap-select/examples/. This because browsers such as IE do not allow styling of options within elements. Chrome/OSX also has this problem - you cannot style options.

However a warning is attached to that approach. These types of menus work very differently on mobile platforms because native elements aren't used. They can have annoying quirks on desktop as well. My advice is 1) don't write your own and 2) find a library that's been really well tested.

Getting Excel to refresh data on sheet from within VBA

This should do the trick...

'recalculate all open workbooks
Application.Calculate

'recalculate a specific worksheet
Worksheets(1).Calculate

' recalculate a specific range
Worksheets(1).Columns(1).Calculate

How to change SmartGit's licensing option after 30 days of commercial use on ubuntu?

I went on the internet and I found this:

To alter the license. First, go to

Windows: %APPDATA%\syntevo\SmartGit&lt;main-smartgit-version>

Windows portable: SmartGit\.settings\preferences.yml

OS X: ~/Library/Preferences/SmartGit/<main-smartgit-version>

Unix/Linux: ~/.smartgit/<main-smartgit-version>

and remove the file settings.xml.

If you have updated many times, you may need to remove the updates folder as well.

It helped me on Windows, hope it helps you on other systems as well.

Difference between [routerLink] and routerLink

Router Link

routerLink with brackets and none - simple explanation.

The difference between routerLink= and [routerLink] is mostly like relative and absolute path.

Similar to a href you may want to navigate to ./about.html or https://your-site.com/about.html.

When you use without brackets then you navigate relative and without params;

my-app.com/dashboard/client

"jumping" from my-app.com/dashboard to my-app.com/dashboard/client

<a routerLink="client/{{ client.id }}" .... rest the same

When you use routerLink with brackets then you execute app to navigate absolute and you can add params how is the puzzle of your new link

first of all it will not include the "jump" from dashboard/ to dashboard/client/client-id and bring you data of client/client-id which is more helpful for EDIT CLIENT

<a [routerLink]="['/client', client.id]" ... rest the same

The absolute way or brackets routerLink require additional set up of you components and app.routing.module.ts

The code without error will "tell you more/what is the purpose of []" when you make the test. Just check this with or without []. Than you may experiments with selectors which - as mention above - helps with dynamics routing.

Angular.io Selectors

See whats the routerLink construct

https://angular.io/api/router/RouterLink#selectors

Calling a function in jQuery with click()

$("#closeLink").click(closeIt);

Let's say you want to call your function passing some args to it i.e., closeIt(1, false). Then, you should build an anonymous function and call closeIt from it.

$("#closeLink").click(function() {
    closeIt(1, false);
});

How do I get and set Environment variables in C#?

Use the System.Environment class.

The methods

var value = System.Environment.GetEnvironmentVariable(variable [, Target])

and

System.Environment.SetEnvironmentVariable(variable, value [, Target])

will do the job for you.

The optional parameter Target is an enum of type EnvironmentVariableTarget and it can be one of: Machine, Process, or User. If you omit it, the default target is the current process.

What is the difference between json.dumps and json.load?

dumps takes an object and produces a string:

>>> a = {'foo': 3}
>>> json.dumps(a)
'{"foo": 3}'

load would take a file-like object, read the data from that object, and use that string to create an object:

with open('file.json') as fh:
    a = json.load(fh)

Note that dump and load convert between files and objects, while dumps and loads convert between strings and objects. You can think of the s-less functions as wrappers around the s functions:

def dump(obj, fh):
    fh.write(dumps(obj))

def load(fh):
    return loads(fh.read())

Regex pattern including all special characters

To find any number of special characters use the following regex pattern: ([^(A-Za-z0-9 )]{1,})

[^(A-Za-z0-9 )] this means any character except the alphabets, numbers, and space. {1,0} this means one or more characters of the previous block.

Multiple INSERT statements vs. single INSERT with multiple VALUES

I ran into a similar situation trying to convert a table with several 100k rows with a C++ program (MFC/ODBC).

Since this operation took a very long time, I figured bundling multiple inserts into one (up to 1000 due to MSSQL limitations). My guess that a lot of single insert statements would create an overhead similar to what is described here.

However, it turns out that the conversion took actually quite a bit longer:

        Method 1       Method 2     Method 3 
        Single Insert  Multi Insert Joined Inserts
Rows    1000           1000         1000
Insert  390 ms         765 ms       270 ms
per Row 0.390 ms       0.765 ms     0.27 ms

So, 1000 single calls to CDatabase::ExecuteSql each with a single INSERT statement (method 1) are roughly twice as fast as a single call to CDatabase::ExecuteSql with a multi-line INSERT statement with 1000 value tuples (method 2).

Update: So, the next thing I tried was to bundle 1000 separate INSERT statements into a single string and have the server execute that (method 3). It turns out this is even a bit faster than method 1.

Edit: I am using Microsoft SQL Server Express Edition (64-bit) v10.0.2531.0

Rails: FATAL - Peer authentication failed for user (PG::Error)

For permanent solution:

The problem is with your pg_hba. This line:

local   all             postgres                                peer

Should be

local   all             postgres                                md5

Then restart your postgresql server after changing this file.

If you're on Linux, command would be

sudo service postgresql restart

checking if a number is divisible by 6 PHP

So you want the next multiple of 6, is that it?

You can divide your number by 6, then ceil it, and multiply it again:

$answer = ceil($foo / 6) * 6;

javascript cell number validation

function IsMobileNumber(txtMobId) {
    var mob = /^[1-9]{1}[0-9]{9}$/;
    var txtMobile = document.getElementById(txtMobId);
    if (mob.test(txtMobile.value) == false) {
        alert("Please enter valid mobile number.");
        txtMobile.focus();
        return false;
    }
    return true;
}

Calling Validation Mobile Number Function HTML Code -

How to determine a user's IP address in node

If using express...

req.ip

I was looking this up then I was like wait, I'm using express. Duh.

The instance of entity type cannot be tracked because another instance of this type with the same key is already being tracked

public async Task<Product> GetValue(int id)
    {
        Product Products = await _context.Products.AsNoTracking().FirstOrDefaultAsync(x => x.Id == id);
        return Products;
    }

AsNoTracking()

What parameters should I use in a Google Maps URL to go to a lat-lon?

This works to zoom into an area more then drop a pin: https://www.google.com/maps/@30.2,17.9820525,9z

And the params are:

@lat,lng,zoom