SyntaxFix

Programs & Examples On #Hibernate session

A main Java interface to Hibernate persistence service.

org.hibernate.QueryException: could not resolve property: filename

Hibernate queries are case sensitive with property names (because they end up relying on getter/setter methods on the @Entity).

Make sure you refer to the property as fileName in the Criteria query, not filename.

Specifically, Hibernate will call the getter method of the filename property when executing that Criteria query, so it will look for a method called getFilename(). But the property is called FileName and the getter getFileName().

So, change the projection like so: 

criteria.setProjection(Projections.property("fileName"));

Unknown version of Tomcat was specified in Eclipse

Having installed tomcat with brew the solution for me was:

sudo chmod -R 777 /usr/local/Cellar/tomcat/<your_version>

How do I force a vertical scrollbar to appear?

Give your body tag an overflow: scroll;

body {
    overflow: scroll;
}

or if you only want a vertical scrollbar use overflow-y

body {
    overflow-y: scroll;
}

Convert and format a Date in JSP

 
<%@page import="java.text.SimpleDateFormat"%>
<%@page import="java.util.Date"%>
<%@page import="java.util.Locale"%>

<html>
<head>
<title>Date Format</title>
</head>
<body>
<%
String stringDate = "Fri May 13 2011 19:59:09 GMT 0530";
Date stringDate1 = new SimpleDateFormat("EEE MMM dd yyyy HH:mm:ss Z", Locale.ENGLISH).parse(stringDate);
String stringDate2 = new SimpleDateFormat("yyyy-MM-dd HH:mm:ss").format(stringDate1);

out.println(stringDate2);
%>
</body>
</html>

What is the most efficient way to check if a value exists in a NumPy array?

To check multiple values, you can use numpy.in1d(), which is an element-wise function version of the python keyword in. If your data is sorted, you can use numpy.searchsorted():

import numpy as np
data = np.array([1,4,5,5,6,8,8,9])
values = [2,3,4,6,7]
print np.in1d(values, data)

index = np.searchsorted(data, values)
print data[index] == values

What are the ways to make an html link open a folder

You can also copy the link address and paste it in a new window to get around the security. This works in chrome and firefox but you may have to add slashes in firefox.

Adding days to a date in Python

Here is a function of getting from now + specified days

import datetime

def get_date(dateFormat="%d-%m-%Y", addDays=0):

    timeNow = datetime.datetime.now()
    if (addDays!=0):
        anotherTime = timeNow + datetime.timedelta(days=addDays)
    else:
        anotherTime = timeNow

    return anotherTime.strftime(dateFormat)

Usage:

addDays = 3 #days
output_format = '%d-%m-%Y'
output = get_date(output_format, addDays)
print output

OPTION (RECOMPILE) is Always Faster; Why?

Often when there is a drastic difference from run to run of a query I find that it is often one of 5 issues.

  1. STATISTICS - Statistics are out of date. A database stores statistics on the range and distribution of the types of values in various column on tables and indexes. This helps the query engine to develop a "Plan" of attack for how it will do the query, for example the type of method it will use to match keys between tables using a hash or looking through the entire set. You can call Update Statistics on the entire database or just certain tables or indexes. This slows down the query from one run to another because when statistics are out of date, its likely the query plan is not optimal for the newly inserted or changed data for the same query (explained more later below). It may not be proper to Update Statistics immediately on a Production database as there will be some overhead, slow down and lag depending on the amount of data to sample. You can also choose to use a Full Scan or Sampling to update Statistics. If you look at the Query Plan, you can then also view the statistics on the Indexes in use such using the command DBCC SHOW_STATISTICS (tablename, indexname). This will show you the distribution and ranges of the keys that the query plan is using to base its approach on.

  2. PARAMETER SNIFFING - The query plan that is cached is not optimal for the particular parameters you are passing in, even though the query itself has not changed. For example, if you pass in a parameter which only retrieves 10 out of 1,000,000 rows, then the query plan created may use a Hash Join, however if the parameter you pass in will use 750,000 of the 1,000,000 rows, the plan created may be an index scan or table scan. In such a situation you can tell the SQL statement to use the option OPTION (RECOMPILE) or an SP to use WITH RECOMPILE. To tell the Engine this is a "Single Use Plan" and not to use a Cached Plan which likely does not apply. There is no rule on how to make this decision, it depends on knowing the way the query will be used by users.

  3. INDEXES - Its possible that the query haven't changed, but a change elsewhere such as the removal of a very useful index has slowed down the query.

  4. ROWS CHANGED - The rows you are querying drastically changes from call to call. Usually statistics are automatically updated in these cases. However if you are building dynamic SQL or calling SQL within a tight loop, there is a possibility you are using an outdated Query Plan based on the wrong drastic number of rows or statistics. Again in this case OPTION (RECOMPILE) is useful.

  5. THE LOGIC Its the Logic, your query is no longer efficient, it was fine for a small number of rows, but no longer scales. This usually involves more indepth analysis of the Query Plan. For example, you can no longer do things in bulk, but have to Chunk things and do smaller Commits, or your Cross Product was fine for a smaller set but now takes up CPU and Memory as it scales larger, this may also be true for using DISTINCT, you are calling a function for every row, your key matches don't use an index because of CASTING type conversion or NULLS or functions... Too many possibilities here.

In general when you write a query, you should have some mental picture of roughly how certain data is distributed within your table. A column for example, can have an evenly distributed number of different values, or it can be skewed, 80% of the time have a specific set of values, whether the distribution will varying frequently over time or be fairly static. This will give you a better idea of how to build an efficient query. But also when debugging query performance have a basis for building a hypothesis as to why it is slow or inefficient.

Disable / Check for Mock Location (prevent gps spoofing)

If you happened to know the general location of cell towers, you could check to see if the current cell tower matches the location given (within an error margin of something large, like 10 or more miles).

For example, if your app unlocks features only if the user is in a specific location (your store, for example), you could check gps as well as cell towers. Currently, no gps spoofing app also spoofs the cell towers, so you could see if someone across the country is simply trying to spoof their way into your special features (I'm thinking of the Disney Mobile Magic app, for one example).

This is how the Llama app manages location by default, since checking cell tower ids are much less battery intensive than gps. It isn't useful for very specific locations, but if home and work are several miles away, it can distinguish between the two general locations very easily.

Of course, this would require the user to have a cell signal at all. And you would have to know all the cell towers ids in the area --on all network providers-- or you would run the risk of a false negative.

Iterating over arrays in Python 3

While iterating over a list or array with this method:

ar = [10, 11, 12]
for i in ar:
    theSum = theSum + ar[i]

You are actually getting the values of list or array sequentially in i variable. If you print the variable i inside the for loop. You will get following output:

10
11
12

However, in your code you are confusing i variable with index value of array. Therefore, while doing ar[i] will mean ar[10] for the first iteration. Which is of course index out of range throwing IndexError

Edit You can read this for better understanding of different methods of iterating over array or list in Python

How can I group data with an Angular filter?

Update

I initially wrote this answer because the old version of the solution suggested by Ariel M. when combined with other $filters triggered an "Infite $diggest Loop Error" (infdig). Fortunately this issue has been solved in the latest version of the angular.filter.

I suggested the following implementation, that didn't have that issue:

angular.module("sbrpr.filters", [])
.filter('groupBy', function () {
  var results={};
    return function (data, key) {
        if (!(data && key)) return;
        var result;
        if(!this.$id){
            result={};
        }else{
            var scopeId = this.$id;
            if(!results[scopeId]){
                results[scopeId]={};
                this.$on("$destroy", function() {
                    delete results[scopeId];
                });
            }
            result = results[scopeId];
        }

        for(var groupKey in result)
          result[groupKey].splice(0,result[groupKey].length);

        for (var i=0; i<data.length; i++) {
            if (!result[data[i][key]])
                result[data[i][key]]=[];
            result[data[i][key]].push(data[i]);
        }

        var keys = Object.keys(result);
        for(var k=0; k<keys.length; k++){
          if(result[keys[k]].length===0)
            delete result[keys[k]];
        }
        return result;
    };
});

However, this implementation will only work with versions prior to Angular 1.3. (I will update this answer shortly providing a solution that works with all versions.)

I've actually wrote a post about the steps that I took to develop this $filter, the problems that I encountered and the things that I learned from it.

How to add a file to the last commit in git?

Yes, there's a command git commit --amend which is used to "fix" last commit.

In your case it would be called as:

git add the_left_out_file
git commit --amend --no-edit

The --no-edit flag allow to make amendment to commit without changing commit message.

EDIT: Warning You should never amend public commits, that you already pushed to public repository, because what amend does is actually removing from history last commit and creating new commit with combined changes from that commit and new added when amending.

Convert normal Java Array or ArrayList to Json Array in android

example key = "Name" value = "Xavier" and the value depends on number of array you pass in

 try
      {
      JSONArray jArry=new JSONArray();
      for (int i=0;i<3;i++)
      {
       JSONObject jObjd=new JSONObject();
       jObjd.put("key", value);
       jObjd.put("key", value);
       jArry.put(jObjd);
      }
      Log.e("Test", jArry.toString());
      }
 catch(JSONException ex)
     {

     }

Center Triangle at Bottom of Div

You could also use a CSS "calc" to get the same effect instead of using the negative margin or transform properties (in case you want to use those properties for anything else).

.hero:after,
.hero:after {
    z-index: -1;
    position: absolute;
    top: 98.1%;
    left: calc(50% - 25px);
    content: '';
    width: 0;
    height: 0;
    border-top: solid 50px #e15915;
    border-left: solid 50px transparent;
    border-right: solid 50px transparent;
}

PHP Warning: PHP Startup: Unable to load dynamic library

I had the same problem on XAMPP for Windows10 when I try to install composer.

Unable to load dynamic library '/xampp/php/ext/php_bz2.dll'

Then follow this steps

  1. just open your current_xampp_containing_drive:\xampp(default_xampp_folder)\php\php.ini in texteditor (like notepad++)
  2. now just find - is the current_xampp_containing_drive:\xampp exist?
  3. if not then find the "extension_dir" and get the drive name(c,d or your desired drive) like.

extension_dir="F:\xampp731\php\ext" (here finded_drive_name_from_the_file is F)

  1. again replace with finded_drive_name_from_the_file:\xampp with current_xampp_containing_drive:\xampp and save.
  2. now again start the composer installation progress, i think your problem will be solved.

List comprehension on a nested list?

If you don't like nested list comprehensions, you can make use of the map function as well, 

>>> from pprint import pprint

>>> l = l = [['40', '20', '10', '30'], ['20', '20', '20', '20', '20', '30', '20'], ['30', '20', '30', '50', '10', '30', '20', '20', '20'], ['100', '100'], ['100', '100', '100', '100', '100'], ['100', '100', '100', '100']] 

>>> pprint(l)
[['40', '20', '10', '30'],
['20', '20', '20', '20', '20', '30', '20'],
['30', '20', '30', '50', '10', '30', '20', '20', '20'],
['100', '100'],
['100', '100', '100', '100', '100'],
['100', '100', '100', '100']]

>>> float_l = [map(float, nested_list) for nested_list in l]

>>> pprint(float_l)
[[40.0, 20.0, 10.0, 30.0],
[20.0, 20.0, 20.0, 20.0, 20.0, 30.0, 20.0],
[30.0, 20.0, 30.0, 50.0, 10.0, 30.0, 20.0, 20.0, 20.0],
[100.0, 100.0],
[100.0, 100.0, 100.0, 100.0, 100.0],
[100.0, 100.0, 100.0, 100.0]]

How to split a string in Java

You can try like this also

 String concatenated_String="hi^Hello";

 String split_string_array[]=concatenated_String.split("\\^");

PHP preg_match - only allow alphanumeric strings and - _ characters

\w\- is probably the best but here just another alternative
Use [:alnum:]

if(!preg_match("/[^[:alnum:]\-_]/",$str)) echo "valid";

demo1 | demo2

How can I select rows with most recent timestamp for each key value?

This can de done in a relatively elegant way using SELECT DISTINCT, as follows:

SELECT DISTINCT ON (sensorID)
sensorID, timestamp, sensorField1, sensorField2 
FROM sensorTable
ORDER BY sensorID, timestamp DESC;

The above works for PostgreSQL (some more info here) but I think also other engines. In case it's not obvious, what this does is sort the table by sensor ID and timestamp (newest to oldest), and then returns the first row (i.e. latest timestamp) for each unique sensor ID.

In my use case I have ~10M readings from ~1K sensors, so trying to join the table with itself on a timestamp-based filter is very resource-intensive; the above takes a couple of seconds.

Limit Get-ChildItem recursion depth

As of powershell 5.0, you can now use the -Depth parameter in Get-ChildItem!

You combine it with -Recurse to limit the recursion.

Get-ChildItem -Recurse -Depth 2

HTML: How to center align a form

simple way:Add a "center" tag before the form tag

Differences in boolean operators: & vs && and | vs ||

If an expression involving the Boolean & operator is evaluated, both operands are evaluated. Then the & operator is applied to the operand.

When an expression involving the && operator is evaluated, the first operand is evaluated. If the first operand evaluates to false, the evaluation of the second operand is skipped.

If the first operand returns a value of true then the second operand is evaluated. If the second operand returns a value of true then && operator is then applied to the first and second operands.

Similar for | and ||.

Python convert object to float

I eventually used:

weather["Temp"] = weather["Temp"].convert_objects(convert_numeric=True)

It worked just fine, except that I got the following message.

C:\ProgramData\Anaconda3\lib\site-packages\ipykernel_launcher.py:3: FutureWarning:
convert_objects is deprecated.  Use the data-type specific converters pd.to_datetime, pd.to_timedelta and pd.to_numeric.

Could not find com.google.android.gms:play-services:3.1.59 3.2.25 4.0.30 4.1.32 4.2.40 4.2.42 4.3.23 4.4.52 5.0.77 5.0.89 5.2.08 6.1.11 6.1.71 6.5.87

I too had the same problem and resolved.

As per the above-mentioned solutions by others, I tried all the things and it does not solve my problem.

Even if you have two SDK locations, no need to worry about it and check whether your android home is set to Android studio SDK (If you have the Android repository and everything in that SDK location).

Solution:

  • Go to Your project structure
  • Select your modules
  • Click the dependance tap on the right side
  • Add library dependency
  • "com.google.android.gms:play-service:+"

I hope it will solve your problem.

Checking if a list is empty with LINQ

Another idea:

if(enumerable.FirstOrDefault() != null)

However I like the Any() approach more.

How to turn a vector into a matrix in R?

Just use matrix:

matrix(vec,nrow = 7,ncol = 7)

One advantage of using matrix rather than simply altering the dimension attribute as Gavin points out, is that you can specify whether the matrix is filled by row or column using the byrow argument in matrix.

python JSON object must be str, bytes or bytearray, not 'dict

json.dumps() is used to decode JSON data

import json

# initialize different data
str_data = 'normal string'
int_data = 1
float_data = 1.50
list_data = [str_data, int_data, float_data]
nested_list = [int_data, float_data, list_data]
dictionary = {
    'int': int_data,
    'str': str_data,
    'float': float_data,
    'list': list_data,
    'nested list': nested_list
}

# convert them to JSON data and then print it
print('String :', json.dumps(str_data))
print('Integer :', json.dumps(int_data))
print('Float :', json.dumps(float_data))
print('List :', json.dumps(list_data))
print('Nested List :', json.dumps(nested_list, indent=4))
print('Dictionary :', json.dumps(dictionary, indent=4))  # the json data will be indented

output:

String : "normal string"
Integer : 1
Float : 1.5
List : ["normal string", 1, 1.5]
Nested List : [
    1,
    1.5,
    [
        "normal string",
        1,
        1.5
    ]
]
Dictionary : {
    "int": 1,
    "str": "normal string",
    "float": 1.5,
    "list": [
        "normal string",
        1,
        1.5
    ],
    "nested list": [
        1,
        1.5,
        [
            "normal string",
            1,
            1.5
        ]
    ]
}
  • Python Object to JSON Data Conversion
|                 Python                 |  JSON  |
|:--------------------------------------:|:------:|
|                  dict                  | object |
|               list, tuple              |  array |
|                   str                  | string |
| int, float, int- & float-derived Enums | number |
|                  True                  |  true  |
|                  False                 |  false |
|                  None                  |  null  |

json.loads() is used to convert JSON data into Python data.

import json

# initialize different JSON data
arrayJson = '[1, 1.5, ["normal string", 1, 1.5]]'
objectJson = '{"a":1, "b":1.5 , "c":["normal string", 1, 1.5]}'

# convert them to Python Data
list_data = json.loads(arrayJson)
dictionary = json.loads(objectJson)

print('arrayJson to list_data :\n', list_data)
print('\nAccessing the list data :')
print('list_data[2:] =', list_data[2:])
print('list_data[:1] =', list_data[:1])

print('\nobjectJson to dictionary :\n', dictionary)
print('\nAccessing the dictionary :')
print('dictionary[\'a\'] =', dictionary['a'])
print('dictionary[\'c\'] =', dictionary['c'])

output:

arrayJson to list_data :
 [1, 1.5, ['normal string', 1, 1.5]]

Accessing the list data :
list_data[2:] = [['normal string', 1, 1.5]]
list_data[:1] = [1]

objectJson to dictionary :
 {'a': 1, 'b': 1.5, 'c': ['normal string', 1, 1.5]}

Accessing the dictionary :
dictionary['a'] = 1
dictionary['c'] = ['normal string', 1, 1.5]
  • JSON Data to Python Object Conversion
|      JSON     | Python |
|:-------------:|:------:|
|     object    |  dict  |
|     array     |  list  |
|     string    |   str  |
|  number (int) |   int  |
| number (real) |  float |
|      true     |  True  |
|     false     |  False |

Node.js - SyntaxError: Unexpected token import

My project uses node v10.21.0, which still does not support ES6 import keyword. There are multiple ways to make node recognize import, one of them is to start node with node --experimental-modules index.mjs (The mjs extension is already covered in one of the answers here). But, this way, you will not be able to use node specific keyword like require in your code. If there is need to use both nodejs's require keyword along with ES6's import, then the way out is to use the esm npm package. After adding esm package as a dependency, node needs to be started with a special configuration like: node -r esm index.js

Multiple line comment in Python

Try this

'''
This is a multiline
comment. I can type here whatever I want.
'''

Python does have a multiline string/comment syntax in the sense that unless used as docstrings, multiline strings generate no bytecode -- just like #-prepended comments. In effect, it acts exactly like a comment.

On the other hand, if you say this behavior must be documented in the official docs to be a true comment syntax, then yes, you would be right to say it is not guaranteed as part of the language specification.

In any case your editor should also be able to easily comment-out a selected region (by placing a # in front of each line individually). If not, switch to an editor that does.

Programming in Python without certain text editing features can be a painful experience. Finding the right editor (and knowing how to use it) can make a big difference in how the Python programming experience is perceived.

Not only should the editor be able to comment-out selected regions, it should also be able to shift blocks of code to the left and right easily, and should automatically place the cursor at the current indentation level when you press Enter. Code folding can also be useful.

Insert multiple rows with one query MySQL

While inserting multiple rows with a single INSERT statement is generally faster, it leads to a more complicated and often unsafe code. Below I present the best practices when it comes to inserting multiple records in one go using PHP.

To insert multiple new rows into the database at the same time, one needs to follow the following 3 steps:

  1. Start transaction (disable autocommit mode)
  2. Prepare INSERT statement
  3. Execute it multiple times

Using database transactions ensures that the data is saved in one piece and significantly improves performance.

How to properly insert multiple rows using PDO

PDO is the most common choice of database extension in PHP and inserting multiple records with PDO is quite simple.

$pdo = new \PDO("mysql:host=localhost;dbname=test;charset=utf8mb4", 'user', 'password', [
    \PDO::ATTR_ERRMODE => \PDO::ERRMODE_EXCEPTION,
    \PDO::ATTR_EMULATE_PREPARES => false
]);

// Start transaction
$pdo->beginTransaction();

// Prepare statement
$stmt = $pdo->prepare('INSERT 
    INTO `pxlot` (realname,email,address,phone,status,regtime,ip) 
    VALUES (?,?,?,?,?,?,?)');

// Perform execute() inside a loop
// Sample data coming from a fictitious data set, but the data can come from anywhere
foreach ($dataSet as $data) {
    // All seven parameters are passed into the execute() in a form of an array
    $stmt->execute([$data['name'], $data['email'], $data['address'], getPhoneNo($data['name']), '0', $data['regtime'], $data['ip']]);
}

// Commit the data into the database
$pdo->commit();

How to properly insert multiple rows using mysqli

The mysqli extension is a little bit more cumbersome to use but operates on very similar principles. The function names are different and take slightly different parameters.

mysqli_report(MYSQLI_REPORT_ERROR | MYSQLI_REPORT_STRICT);
$mysqli = new \mysqli('localhost', 'user', 'password', 'database');
$mysqli->set_charset('utf8mb4');

// Start transaction
$mysqli->begin_transaction();

// Prepare statement
$stmt = $mysqli->prepare('INSERT 
    INTO `pxlot` (realname,email,address,phone,status,regtime,ip) 
    VALUES (?,?,?,?,?,?,?)');

// Perform execute() inside a loop
// Sample data coming from a fictitious data set, but the data can come from anywhere
foreach ($dataSet as $data) {
    // mysqli doesn't accept bind in execute yet, so we have to bind the data first
    // The first argument is a list of letters denoting types of parameters. It's best to use 's' for all unless you need a specific type
    // bind_param doesn't accept an array so we need to unpack it first using '...'
    $stmt->bind_param('sssssss', ...[$data['name'], $data['email'], $data['address'], getPhoneNo($data['name']), '0', $data['regtime'], $data['ip']]);
    $stmt->execute();
}

// Commit the data into the database
$mysqli->commit();

Performance

Both extensions offer the ability to use transactions. Executing prepared statement with transactions greatly improves performance, but it's still not as good as a single SQL query. However, the difference is so negligible that for the sake of conciseness and clean code it is perfectly acceptable to execute prepared statements multiple times. If you need a faster option to insert many records into the database at once, then chances are that PHP is not the right tool.

Adding a default value in dropdownlist after binding with database

The solution provided by Justin should work. To be sure making use of SelectedIndex property will also help.

ddlColor.DataSource = from p in db.ProductTypes
                      where p.ProductID == pID
                      orderby p.Color
                      select new { p.Color };

ddlColor.DataTextField = "Color";
ddlColor.DataBind();

ddlColor.Items.Insert(0, new ListItem("Select Color", ""); 
ddlColor.SelectedIndex = 0;

Factory Pattern. When to use factory methods?

It is important to clearly differentiate the idea behind using factory or factory method. Both are meant to address mutually exclusive different kind of object creation problems.

Let's be specific about "factory method":

First thing is that, when you are developing library or APIs which in turn will be used for further application development, then factory method is one of the best selections for creation pattern. Reason behind; We know that when to create an object of required functionality(s) but type of object will remain undecided or it will be decided ob dynamic parameters being passed.

Now the point is, approximately same can be achieved by using factory pattern itself but one huge drawback will introduce into the system if factory pattern will be used for above highlighted problem, it is that your logic of crating different objects(sub classes objects) will be specific to some business condition so in future when you need to extend your library's functionality for other platforms(In more technically, you need to add more sub classes of basic interface or abstract class so factory will return those objects also in addition to existing one based on some dynamic parameters) then every time you need to change(extend) the logic of factory class which will be costly operation and not good from design perspective. On the other side, if "factory method" pattern will be used to perform the same thing then you just need to create additional functionality(sub classes) and get it registered dynamically by injection which doesn't require changes in your base code.

interface Deliverable 
{
    /*********/
}

abstract class DefaultProducer 
{

    public void taskToBeDone() 
    {   
        Deliverable deliverable = factoryMethodPattern();
    }
    protected abstract Deliverable factoryMethodPattern();
}

class SpecificDeliverable implements Deliverable 
{
 /***SPECIFIC TASK CAN BE WRITTEN HERE***/
}

class SpecificProducer extends DefaultProducer 
{
    protected Deliverable factoryMethodPattern() 
    {
        return new SpecificDeliverable();
    }
}

public class MasterApplicationProgram 
{
    public static void main(String arg[]) 
    {
        DefaultProducer defaultProducer = new SpecificProducer();
        defaultProducer.taskToBeDone();
    }
}

Adding multiple class using ng-class

To apply different classes when different expressions evaluate to true:

<div ng-class="{class1 : expression1, class2 : expression2}">
    Hello World!
</div>

To apply multiple classes when an expression holds true:

<!-- notice expression1 used twice -->
<div ng-class="{class1 : expression1, class2 : expression1}">
    Hello World!
</div>

or quite simply:

<div ng-class="{'class1 class2' : expression1}">
    Hello World!
</div>

Notice the single quotes surrounding css classes.

What is the difference between .text, .value, and .value2?

Except first answer form Bathsheba, except MSDN information for:

.Value
.Value2
.Text

you could analyse these tables for better understanding of differences between analysed properties.

enter image description here

Better way to convert an int to a boolean

I assume 0 means false (which is the case in a lot of programming languages). That means true is not 0 (some languages use -1 some others use 1; doesn't hurt to be compatible to either). So assuming by "better" you mean less typing, you can just write:

bool boolValue = intValue != 0;

Send inline image in email

Some minimal c# code to embed an image, can be:

MailMessage mailWithImg = GetMailWithImg();
MySMTPClient.Send(mailWithImg); //* Set up your SMTPClient before!

private MailMessage GetMailWithImg() {
    MailMessage mail = new MailMessage();
    mail.IsBodyHtml = true;
    mail.AlternateViews.Add(GetEmbeddedImage("c:/image.png"));
    mail.From = new MailAddress("yourAddress@yourDomain");
    mail.To.Add("recipient@hisDomain");
    mail.Subject = "yourSubject";
    return mail;
}

private AlternateView GetEmbeddedImage(String filePath) {
    LinkedResource res = new LinkedResource(filePath);
    res.ContentId = Guid.NewGuid().ToString();
    string htmlBody = @"<img src='cid:" + res.ContentId + @"'/>";
    AlternateView alternateView = AlternateView.CreateAlternateViewFromString(htmlBody, null, MediaTypeNames.Text.Html);
    alternateView.LinkedResources.Add(res);
    return alternateView;
}

json Uncaught SyntaxError: Unexpected token :

I had the same problem and the solution was to encapsulate the json inside this function

jsonp(

.... your json ...

)

No 'Access-Control-Allow-Origin' header is present on the requested resource error

For development you can use https://cors-anywhere.herokuapp.com , for production is better to set up your own proxy

_x000D_
_x000D_ 
async function read() {_x000D_
   let r= await (await fetch('https://cors-anywhere.herokuapp.com/http://ajax.googleapis.com/ajax/services/feed/load?v=1.0&num=10&q=http://feeds.feedburner.com/mathrubhumi')).json();_x000D_
   console.log(r);_x000D_
}_x000D_
_x000D_
read();
_x000D_
_x000D_
_x000D_

Difference between nVidia Quadro and Geforce cards?

I have read that while the underlying chips are essentially the same, the design of the board is different.

Gamers want performance, and tend to favor overclocking and other things to get high frame rates but which maybe burn out the hardware occasionally.

Businesses want reliability, and tend to favor underclocking so they can be sure that their people can keep working.

Also, I have read that the quadro boards use ECC memory.

If you don't know what ECC memory is about: it's a [relatively] well known fact that sometimes memory "flips bits (experiences errors)". This does not happen too often, but is an unavoidable consequence of the underlying physics of the memory cards and the world we live in. ECC memory adds a small percentage to the cost and a small penalty to the performance and has enough redundancy to correct occasional errors and to detect (but not correct) somewhat rarer errors. Gamers don't care about that kind of accuracy because for gamers those are just very rare visual glitches. Companies do care about that kind of accuracy because those glitches would wind up as glitches in their products or else would require more double or triple checking (which winds up being a 2x or 3x performance penalty for some part of their business).

Another issue I have read about has to do with hooking up the graphics card to third party hardware. In other words: sending the images to another card or to another machine instead of to the screen. Most gamers are just using canned software that doesn't have any use for such capabilities. Companies that use that kind of thing get orders of magnitude performance gains from the more direct connections.

super() raises "TypeError: must be type, not classobj" for new-style class

You can also use class TextParser(HTMLParser, object):. This makes TextParser a new-style class, and super() can be used.

Cannot implicitly convert type 'System.DateTime?' to 'System.DateTime'. An explicit conversion exists

dt is nullable you need to access its Value

if (datetime.HasValue)
    dt = datetime.Value;

It is important to remember that it can be NULL. That is why the nullablestruct has the HasValue property that tells you if it is NULL or not.

You can also use the null-coalescing operator ?? to assign a default value

dt = datetime ?? DateTime.Now;

This will assign the value on the right if the value on the left is NULL

Background Image for Select (dropdown) does not work in Chrome

 
select 
{
    -webkit-appearance: none;
}

If you need to you can also add an image that contains the arrow as part of the background.

NuGet: 'X' already has a dependency defined for 'Y'
  1. Go to Tools.
  2. Extensions and Updates.
  3. Update Nuget and any other important feature.
  4. Restart.

Done.

Class JavaLaunchHelper is implemented in two places

I have found the other workaround: to exclude libinstrument.dylib from project path. To do so, go to the Preferences -> Build, Execution and Deployment -> Compiler -> Excludes -> + and here add file by the path in error message.

Virtualenv Command Not Found

Make sure that you are using

sudo

In this case, at first you need to uninstall the pipenv and then install again using sudo command.

  1. pip uninstall pipenv
  2. sudo pip install pipenv

importing a CSV into phpmyadmin

In phpMyAdmin, click the table, and then click the Import tab at the top of the page.

Browse and open the csv file. Leave the charset as-is. Uncheck partial import unless you have a HUGE dataset (or slow server). The format should already have selected “CSV” after selecting your file, if not then select it (not using LOAD DATA). If you want to clear the whole table before importing, check “Replace table data with file”. Optionally check “Ignore duplicate rows” if you think you have duplicates in the CSV file. Now the important part, set the next four fields to these values:

Fields terminated by: ,
Fields enclosed by: “
Fields escaped by: \
Lines terminated by: auto

Currently these match the defaults except for “Fields terminated by”, which defaults to a semicolon.

Now click the Go button, and it should run successfully.

How do I deal with installing peer dependencies in Angular CLI?

NPM package libraries have a section in the package.json file named peerDependencies. For example; a library built in Angular 8, will usually list Angular 8 as a dependency. This is a true dependency for anyone running less than version 8. But for anyone running version 8, 9 or 10, it's questionable whether any concern should be pursued.

I have been safely ignoring these messages on Angular Updates, but then again we do have Unit and Cypress Tests!

Select query to get data from SQL Server

you have to add parameter also @zip

 SqlConnection conn = new SqlConnection("Data Source=;Initial Catalog=;Persist Security Info=True;User ID=;Password=");
      conn.Open();
      SqlCommand command = new SqlCommand("Select id from [table1] where name=@zip", conn);
      //
    // Add new SqlParameter to the command.
    //
      command.Parameters.AddWithValue("@zip","india");
      int result = (Int32) (command.ExecuteScalar());
      using (SqlDataReader reader = command.ExecuteReader())
      {
          // iterate your results here
       Console.WriteLine(String.Format("{0}",reader["id"]));

      }
      conn.Close();

How do I add a placeholder on a CharField in Django?

 
class FormClass(forms.ModelForm):
    class Meta:
        model = Book
        fields = '__all__'
        widgets = {
            'field_name': forms.TextInput(attrs={'placeholder': 'Type placeholder text here..'}),
        }

How do I solve this "Cannot read property 'appendChild' of null" error?

For all those facing a similar issue, I came across this same issue when i was trying to run a particular code snippet, shown below.

<html>
    <head>
        <script>
                var div, container = document.getElementById("container")
                for(var i=0;i<5;i++){
                    div = document.createElement("div");
                    div.onclick = function() { 
                        alert("This is a box #"+i);
                    };
                    container.appendChild(div);
                }
            </script>

    </head>
    <body>
        <div id="container"></div>
    </body>
 </html>

https://codepen.io/pcwanderer/pen/MMEREr

Looking at the error in the console for the above code.

Since the document.getElementById is returning a null and as null does not have a attribute named appendChild, therefore a error is thrown. To solve the issue see the code below.

<html>
    <head>
        <style>
        #container{
            height: 200px;
            width: 700px;
            background-color: red;
            margin: 10px;
        }


        div{
            height: 100px;
            width: 100px;
            background-color: purple;
            margin: 20px;
            display: inline-block;
        }
        </style>
    </head>
    <body>
        <div id="container"></div>
        <script>
                var div, container = document.getElementById("container")
                for(let i=0;i<5;i++){
                    div = document.createElement("div");
                    div.onclick = function() { 
                        alert("This is a box #"+i);
                    };
                    container.appendChild(div);
                }
            </script>
    </body>
</html>

https://codepen.io/pcwanderer/pen/pXWBQL

I hope this helps. :)

Right HTTP status code to wrong input

Codes starting with 4 (4xx) are meant for client errors. Maybe 400 (Bad Request) could be suitable to this case? Definition in http://www.w3.org/Protocols/rfc2616/rfc2616-sec10.html says:

"The request could not be understood by the server due to malformed syntax. The client SHOULD NOT repeat the request without modifications. "

PHP: convert spaces in string into %20?

I believe that, if you need to use the %20 variant, you could perhaps use rawurlencode().

Make error: missing separator

My error was on a variable declaration line with a multi-line extension. I have a trailing space after the "\" which made that an invalid line continuation.

MY_VAR = \
   val1 \ <-- 0x20 there caused the error.
   val2

What is the difference between FragmentPagerAdapter and FragmentStatePagerAdapter?

FragmentStatePagerAdapter:

  • with FragmentStatePagerAdapter,your unneeded fragment is destroyed.A transaction is committed to completely remove the fragment from your activity's FragmentManager.

  • The state in FragmentStatePagerAdapter comes from the fact that it will save out your fragment's Bundle from savedInstanceState when it is destroyed.When the user navigates back,the new fragment will be restored using the fragment's state.

FragmentPagerAdapter:

  • By comparision FragmentPagerAdapter does nothing of the kind.When the fragment is no longer needed.FragmentPagerAdapter calls detach(Fragment) on the transaction instead of remove(Fragment).

  • This destroy's the fragment's view but leaves the fragment's instance alive in the FragmentManager.so the fragments created in the FragmentPagerAdapter are never destroyed.

syntax error near unexpected token `('

Try

sudo -su db2inst1 /opt/ibm/db2/V9.7/bin/db2 force application \(1995\)

"While .. End While" doesn't work in VBA?

VBA is not VB/VB.NET

The correct reference to use is Do..Loop Statement (VBA). Also see the article Excel VBA For, Do While, and Do Until. One way to write this is:

Do While counter < 20
    counter = counter + 1
Loop

(But a For..Next might be more appropriate here.)

Happy coding.

ORA-00942: table or view does not exist (works when a separate sql, but does not work inside a oracle function)

Either u dont have permission to that schema/table OR table does exist. Mostly this issue occurred if you are using other schema tables in your stored procedures. Eg. If you are running Stored Procedure from user/schema ABC and in the same PL/SQL there are tables which is from user/schema XYZ. In this case ABC should have GRANT i.e. privileges of XYZ tables

Grant All On To ABC; 

Select * From Dba_Tab_Privs Where Owner = 'XYZ'and Table_Name = <Table_Name>;

Why is my JavaScript function sometimes "not defined"?

I had this function not being recognized as defined in latest Firefox for Linux, though Chromium was dealing fine with it.

What happened in my case was that I had a former SCRIPT block, before the block that defined the function with problem, stated in the following way:

<SCRIPT src="mycode.js"/>

(That is, without the closing tag.)

I had to redeclare this block in the following way.

<SCRIPT src="mycode.js"></SCRIPT>

And then what followed worked fine... weird huh?

Understanding typedefs for function pointers in C

This is the simplest example of function pointers and function pointer arrays that I wrote as an exercise.

    typedef double (*pf)(double x);  /*this defines a type pf */

    double f1(double x) { return(x+x);}
    double f2(double x) { return(x*x);}

    pf pa[] = {f1, f2};


    main()
    {
        pf p;

        p = pa[0];
        printf("%f\n", p(3.0));
        p = pa[1];
        printf("%f\n", p(3.0));
    }

Add disabled attribute to input element using Javascript

If you're using jQuery then there are a few different ways to set the disabled attribute.

var $element = $(...);
    $element.prop('disabled', true);
    $element.attr('disabled', true); 

    // The following do not require jQuery
    $element.get(0).disabled = true;
    $element.get(0).setAttribute('disabled', true);
    $element[0].disabled = true;
    $element[0].setAttribute('disabled', true);

How to access SVG elements with Javascript

If you are using an <img> tag for the SVG, then you cannot manipulate its contents (as far as I know).

As the accepted answer shows, using <object> is an option.

I needed this recently and used gulp-inject during my gulp build to inject the contents of an SVG file directly into the HTML document as an <svg> element, which is then very easy to work with using CSS selectors and querySelector/getElementBy*.

What is the difference between bottom-up and top-down?

rev4: A very eloquent comment by user Sammaron has noted that, perhaps, this answer previously confused top-down and bottom-up. While originally this answer (rev3) and other answers said that "bottom-up is memoization" ("assume the subproblems"), it may be the inverse (that is, "top-down" may be "assume the subproblems" and "bottom-up" may be "compose the subproblems"). Previously, I have read on memoization being a different kind of dynamic programming as opposed to a subtype of dynamic programming. I was quoting that viewpoint despite not subscribing to it. I have rewritten this answer to be agnostic of the terminology until proper references can be found in the literature. I have also converted this answer to a community wiki. Please prefer academic sources. List of references: {Web: 1,2} {Literature: 5}

Recap

Dynamic programming is all about ordering your computations in a way that avoids recalculating duplicate work. You have a main problem (the root of your tree of subproblems), and subproblems (subtrees). The subproblems typically repeat and overlap.

For example, consider your favorite example of Fibonnaci. This is the full tree of subproblems, if we did a naive recursive call:

TOP of the tree
fib(4)
 fib(3)...................... + fib(2)
  fib(2)......... + fib(1)       fib(1)........... + fib(0)
   fib(1) + fib(0)   fib(1)       fib(1)              fib(0)
    fib(1)   fib(0)
BOTTOM of the tree

(In some other rare problems, this tree could be infinite in some branches, representing non-termination, and thus the bottom of the tree may be infinitely large. Furthermore, in some problems you might not know what the full tree looks like ahead of time. Thus, you might need a strategy/algorithm to decide which subproblems to reveal.)

Memoization, Tabulation

There are at least two main techniques of dynamic programming which are not mutually exclusive:

  • Memoization - This is a laissez-faire approach: You assume that you have already computed all subproblems and that you have no idea what the optimal evaluation order is. Typically, you would perform a recursive call (or some iterative equivalent) from the root, and either hope you will get close to the optimal evaluation order, or obtain a proof that you will help you arrive at the optimal evaluation order. You would ensure that the recursive call never recomputes a subproblem because you cache the results, and thus duplicate sub-trees are not recomputed.

    • example: If you are calculating the Fibonacci sequence fib(100), you would just call this, and it would call fib(100)=fib(99)+fib(98), which would call fib(99)=fib(98)+fib(97), ...etc..., which would call fib(2)=fib(1)+fib(0)=1+0=1. Then it would finally resolve fib(3)=fib(2)+fib(1), but it doesn't need to recalculate fib(2), because we cached it.
    • This starts at the top of the tree and evaluates the subproblems from the leaves/subtrees back up towards the root.

  • Tabulation - You can also think of dynamic programming as a "table-filling" algorithm (though usually multidimensional, this 'table' may have non-Euclidean geometry in very rare cases*). This is like memoization but more active, and involves one additional step: You must pick, ahead of time, the exact order in which you will do your computations. This should not imply that the order must be static, but that you have much more flexibility than memoization.

    • example: If you are performing fibonacci, you might choose to calculate the numbers in this order: fib(2),fib(3),fib(4)... caching every value so you can compute the next ones more easily. You can also think of it as filling up a table (another form of caching).
    • I personally do not hear the word 'tabulation' a lot, but it's a very decent term. Some people consider this "dynamic programming".
    • Before running the algorithm, the programmer considers the whole tree, then writes an algorithm to evaluate the subproblems in a particular order towards the root, generally filling in a table.
    • *footnote: Sometimes the 'table' is not a rectangular table with grid-like connectivity, per se. Rather, it may have a more complicated structure, such as a tree, or a structure specific to the problem domain (e.g. cities within flying distance on a map), or even a trellis diagram, which, while grid-like, does not have a up-down-left-right connectivity structure, etc. For example, user3290797 linked a dynamic programming example of finding the maximum independent set in a tree, which corresponds to filling in the blanks in a tree.

(At it's most general, in a "dynamic programming" paradigm, I would say the programmer considers the whole tree, then writes an algorithm that implements a strategy for evaluating subproblems which can optimize whatever properties you want (usually a combination of time-complexity and space-complexity). Your strategy must start somewhere, with some particular subproblem, and perhaps may adapt itself based on the results of those evaluations. In the general sense of "dynamic programming", you might try to cache these subproblems, and more generally, try avoid revisiting subproblems with a subtle distinction perhaps being the case of graphs in various data structures. Very often, these data structures are at their core like arrays or tables. Solutions to subproblems can be thrown away if we don't need them anymore.)

[Previously, this answer made a statement about the top-down vs bottom-up terminology; there are clearly two main approaches called Memoization and Tabulation that may be in bijection with those terms (though not entirely). The general term most people use is still "Dynamic Programming" and some people say "Memoization" to refer to that particular subtype of "Dynamic Programming." This answer declines to say which is top-down and bottom-up until the community can find proper references in academic papers. Ultimately, it is important to understand the distinction rather than the terminology.]

Pros and cons

Ease of coding

Memoization is very easy to code (you can generally* write a "memoizer" annotation or wrapper function that automatically does it for you), and should be your first line of approach. The downside of tabulation is that you have to come up with an ordering.

*(this is actually only easy if you are writing the function yourself, and/or coding in an impure/non-functional programming language... for example if someone already wrote a precompiled fib function, it necessarily makes recursive calls to itself, and you can't magically memoize the function without ensuring those recursive calls call your new memoized function (and not the original unmemoized function))

Recursiveness

Note that both top-down and bottom-up can be implemented with recursion or iterative table-filling, though it may not be natural.

Practical concerns

With memoization, if the tree is very deep (e.g. fib(10^6)), you will run out of stack space, because each delayed computation must be put on the stack, and you will have 10^6 of them.

Optimality

Either approach may not be time-optimal if the order you happen (or try to) visit subproblems is not optimal, specifically if there is more than one way to calculate a subproblem (normally caching would resolve this, but it's theoretically possible that caching might not in some exotic cases). Memoization will usually add on your time-complexity to your space-complexity (e.g. with tabulation you have more liberty to throw away calculations, like using tabulation with Fib lets you use O(1) space, but memoization with Fib uses O(N) stack space).

Advanced optimizations

If you are also doing a extremely complicated problems, you might have no choice but to do tabulation (or at least take a more active role in steering the memoization where you want it to go). Also if you are in a situation where optimization is absolutely critical and you must optimize, tabulation will allow you to do optimizations which memoization would not otherwise let you do in a sane way. In my humble opinion, in normal software engineering, neither of these two cases ever come up, so I would just use memoization ("a function which caches its answers") unless something (such as stack space) makes tabulation necessary... though technically to avoid a stack blowout you can 1) increase the stack size limit in languages which allow it, or 2) eat a constant factor of extra work to virtualize your stack (ick), or 3) program in continuation-passing style, which in effect also virtualizes your stack (not sure the complexity of this, but basically you will effectively take the deferred call chain from the stack of size N and de-facto stick it in N successively nested thunk functions... though in some languages without tail-call optimization you may have to trampoline things to avoid a stack blowout).

More complicated examples

Here we list examples of particular interest, that are not just general DP problems, but interestingly distinguish memoization and tabulation. For example, one formulation might be much easier than the other, or there may be an optimization which basically requires tabulation:

  • the algorithm to calculate edit-distance[4], interesting as a non-trivial example of a two-dimensional table-filling algorithm

Accessing last x characters of a string in Bash

Last three characters of string:

${string: -3}

or

${string:(-3)}

(mind the space between : and -3 in the first form).

Please refer to the Shell Parameter Expansion in the reference manual:

${parameter:offset}
${parameter:offset:length}

Expands to up to length characters of parameter starting at the character
specified by offset. If length is omitted, expands to the substring of parameter
starting at the character specified by offset. length and offset are arithmetic
expressions (see Shell Arithmetic). This is referred to as Substring Expansion.

If offset evaluates to a number less than zero, the value is used as an offset
from the end of the value of parameter. If length evaluates to a number less than
zero, and parameter is not ‘@’ and not an indexed or associative array, it is
interpreted as an offset from the end of the value of parameter rather than a
number of characters, and the expansion is the characters between the two
offsets. If parameter is ‘@’, the result is length positional parameters
beginning at offset. If parameter is an indexed array name subscripted by ‘@’ or
‘*’, the result is the length members of the array beginning with
${parameter[offset]}. A negative offset is taken relative to one greater than the
maximum index of the specified array. Substring expansion applied to an
associative array produces undefined results.

Note that a negative offset must be separated from the colon by at least one
space to avoid being confused with the ‘:-’ expansion. Substring indexing is
zero-based unless the positional parameters are used, in which case the indexing
starts at 1 by default. If offset is 0, and the positional parameters are used,
$@ is prefixed to the list.

Since this answer gets a few regular views, let me add a possibility to address John Rix's comment; as he mentions, if your string has length less than 3, ${string: -3} expands to the empty string. If, in this case, you want the expansion of string, you may use:

${string:${#string}<3?0:-3}

This uses the ?: ternary if operator, that may be used in Shell Arithmetic; since as documented, the offset is an arithmetic expression, this is valid.

Update for a POSIX-compliant solution

The previous part gives the best option when using Bash. If you want to target POSIX shells, here's an option (that doesn't use pipes or external tools like cut):

# New variable with 3 last characters removed
prefix=${string%???}
# The new string is obtained by removing the prefix a from string
newstring=${string#"$prefix"}

One of the main things to observe here is the use of quoting for prefix inside the parameter expansion. This is mentioned in the POSIX ref (at the end of the section):

The following four varieties of parameter expansion provide for substring processing. In each case, pattern matching notation (see Pattern Matching Notation), rather than regular expression notation, shall be used to evaluate the patterns. If parameter is '#', '*', or '@', the result of the expansion is unspecified. If parameter is unset and set -u is in effect, the expansion shall fail. Enclosing the full parameter expansion string in double-quotes shall not cause the following four varieties of pattern characters to be quoted, whereas quoting characters within the braces shall have this effect. In each variety, if word is omitted, the empty pattern shall be used.

This is important if your string contains special characters. E.g. (in dash),

$ string="hello*ext"
$ prefix=${string%???}
$ # Without quotes (WRONG)
$ echo "${string#$prefix}"
*ext
$ # With quotes (CORRECT)
$ echo "${string#"$prefix"}"
ext

Of course, this is usable only when then number of characters is known in advance, as you have to hardcode the number of ? in the parameter expansion; but when it's the case, it's a good portable solution.

PHP foreach loop key value

You can access your array keys like so:

foreach ($array as $key => $value)

How to create a sticky navigation bar that becomes fixed to the top after scrolling

//in html

<nav class="navbar navbar-default" id="mainnav">
<nav>

// add in jquery

$(document).ready(function() {
  var navpos = $('#mainnav').offset();
  console.log(navpos.top);
    $(window).bind('scroll', function() {
      if ($(window).scrollTop() > navpos.top) {
       $('#mainnav').addClass('navbar-fixed-top');
       }
       else {
         $('#mainnav').removeClass('navbar-fixed-top');
       }
    });
});

Here is the jsfiddle to play around : -http://jsfiddle.net/shubhampatwa/46ovg69z/

EDIT: if you want to apply this code only for mobile devices the you can use:

   var newWindowWidth = $(window).width();
    if (newWindowWidth < 481) {
        //Place code inside it...
       }

DBCC SHRINKFILE on log file not reducing size even after BACKUP LOG TO DISK

I tried many ways but this works.

Sample code is availalbe in DBCC SHRINKFILE

USE DBName;  
GO  
-- Truncate the log by changing the database recovery model to SIMPLE.  
ALTER DATABASE DBName  
SET RECOVERY SIMPLE;  
GO  
-- Shrink the truncated log file to 1 MB.  
DBCC SHRINKFILE (DBName_log, 1);  --File name SELECT * FROM sys.database_files; query to get the file name
GO  
-- Reset the database recovery model.  
ALTER DATABASE DBName  
SET RECOVERY FULL;  
GO

How to change Toolbar home icon color

Instead of style changes, just put these two lines of code to your activity.

getSupportActionBar().setDisplayHomeAsUpEnabled(true);
getSupportActionBar().setHomeAsUpIndicator(R.drawable.arrowleft);

Unix tail equivalent command in Windows Powershell

Probably too late for an answere but, try this one

Get-Content <filename> -tail <number of items wanted>

How to implement OnFragmentInteractionListener

In addition to @user26409021 's answer, If you have added a ItemFragment, The message in the ItemFragment is;

Activities containing this fragment MUST implement the {@link OnListFragmentInteractionListener} interface.

And You should add in your activity;

public class MainActivity extends AppCompatActivity
    implements NavigationView.OnNavigationItemSelectedListener, ItemFragment.OnListFragmentInteractionListener {

//the code is omitted

 public void onListFragmentInteraction(DummyContent.DummyItem uri){
    //you can leave it empty
}

Here the dummy item is what you have on the bottom of your ItemFragment

How to set a binding in Code?

Replace:

myBinding.Source = ViewModel.SomeString;

with:

myBinding.Source = ViewModel;

Example:

Binding myBinding = new Binding();
myBinding.Source = ViewModel;
myBinding.Path = new PropertyPath("SomeString");
myBinding.Mode = BindingMode.TwoWay;
myBinding.UpdateSourceTrigger = UpdateSourceTrigger.PropertyChanged;
BindingOperations.SetBinding(txtText, TextBox.TextProperty, myBinding);

Your source should be just ViewModel, the .SomeString part is evaluated from the Path (the Path can be set by the constructor or by the Path property).

Is there 'byte' data type in C++?

 
namespace std
{
  // define std::byte
  enum class byte : unsigned char {};

};

This if your C++ version does not have std::byte will define a byte type in namespace std. Normally you don't want to add things to std, but in this case it is a standard thing that is missing.

std::byte from the STL does much more operations.

Setting the target version of Java in ant javac

You may also set {{ant.build.javac.target=1.5}} ant property to update default target version of task. See http://ant.apache.org/manual/javacprops.html#target

Base64: java.lang.IllegalArgumentException: Illegal character

I encountered this error since my encoded image started with data:image/png;base64,iVBORw0....

This answer led me to the solution:

String partSeparator = ",";
if (data.contains(partSeparator)) {
  String encodedImg = data.split(partSeparator)[1];
  byte[] decodedImg = Base64.getDecoder().decode(encodedImg.getBytes(StandardCharsets.UTF_8));
  Path destinationFile = Paths.get("/path/to/imageDir", "myImage.jpg");
  Files.write(destinationFile, decodedImg);
}

What does cmd /C mean?

The part you should be interested in is the /? part, which should solve most other questions you have with the tool.

Microsoft Windows XP [Version 5.1.2600]
(C) Copyright 1985-2001 Microsoft Corp.

C:\>cmd /?
Starts a new instance of the Windows XP command interpreter

CMD [/A | /U] [/Q] [/D] [/E:ON | /E:OFF] [/F:ON | /F:OFF] [/V:ON | /V:OFF]
    [[/S] [/C | /K] string]

/C      Carries out the command specified by string and then terminates
/K      Carries out the command specified by string but remains
/S      Modifies the treatment of string after /C or /K (see below)
/Q      Turns echo off
/D      Disable execution of AutoRun commands from registry (see below)
/A      Causes the output of internal commands to a pipe or file to be ANSI
/U      Causes the output of internal commands to a pipe or file to be
        Unicode
/T:fg   Sets the foreground/background colors (see COLOR /? for more info)
/E:ON   Enable command extensions (see below)
/E:OFF  Disable command extensions (see below)
/F:ON   Enable file and directory name completion characters (see below)
/F:OFF  Disable file and directory name completion characters (see below)
/V:ON   Enable delayed environment variable expansion using ! as the
        delimiter. For example, /V:ON would allow !var! to expand the
        variable var at execution time.  The var syntax expands variables
        at input time, which is quite a different thing when inside of a FOR
        loop.
/V:OFF  Disable delayed environment expansion.

How can I create a two dimensional array in JavaScript?

Performance

Today 2020.02.05 I perform tests on MacOs HighSierra 10.13.6 on Chrome v79.0, Safari v13.0.4 and Firefox v72.0, for chosen solutions.

Conclusions for non-initialised 2d array

  • esoteric solution {}/arr[[i,j]] (N) is fastest for big and small arrays and it looks like it is good choice for big sparse arrays
  • solutions based on for-[]/while (A,G) are fast and they are good choice for small arrays.
  • solutions for-[] (B,C) are fast and they are good choice for big arrays
  • solutions based on Array..map/from/fill (I,J,K,L,M) are quite slow for small arrays, and quite fast for big arrays
  • surprinsingly for-Array(n) (B,C) is much slower on safari than for-[] (A)
  • surprinsingly for-[] (A) for big array is slow on all browsers
  • solutions K is slow for small arrays for all browsers
  • solutions A,E,G are slow for big arrays for all browsers
  • solution M is slowest for all arrays on all browsers

enter image description here

Conclusions for initialised 2d array

  • solutions based on for/while (A,B,C,D,E,G) are fastest/quite fast for small arrays on all browsers
  • solutions based on for (A,B,C,E) are fastest/quite fast for big arrays on all browsers
  • solutions based on Array..map/from/fill (I,J,K,L,M) are medium fast or slow for small arrays on all browsers
  • solutions F,G,H,I,J,K,L for big arrays are medium or fast on chrome and safari but slowest on firefox.
  • esoteric solution {}/arr[[i,j]] (N) is slowest for small and big arrays on all browsers

enter image description here

Details

Test for solutions which not fill (initialise) output array

We test speed of solutions for

  • small arrays (12 elements) - you can perform tests on your machine HERE
  • big arrays (1 million elements) arrays - you can perform tests on your machine HERE

_x000D_
_x000D_ 
function A(r) {_x000D_
  var arr = [];_x000D_
  for (var i = 0; i < r; i++) arr[i] = [];_x000D_
  return arr;_x000D_
}_x000D_
_x000D_
function B(r, c) {_x000D_
  var arr = new Array(r);_x000D_
  for (var i = 0; i < arr.length; i++) arr[i] = new Array(c);_x000D_
  return arr;_x000D_
}_x000D_
_x000D_
function C(r, c) {_x000D_
  var arr = Array(r);_x000D_
  for (var i = 0; i < arr.length; i++) arr[i] = Array(c);_x000D_
  return arr;_x000D_
}_x000D_
_x000D_
function D(r, c) {_x000D_
  // strange, but works_x000D_
  var arr = [];_x000D_
  for (var i = 0; i < r; i++) {_x000D_
    arr.push([]);_x000D_
    arr[i].push(Array(c));_x000D_
  }_x000D_
  return arr;_x000D_
}_x000D_
_x000D_
function E(r, c) {_x000D_
  let array = [[]];_x000D_
  for (var x = 0; x < c; x++) {_x000D_
    array[x] = [];_x000D_
    for (var y = 0; y < r; y++) array[x][y] = [0];_x000D_
  }_x000D_
  return array;_x000D_
}_x000D_
_x000D_
function F(r, c) {_x000D_
  var makeArray = function(dims, arr) {_x000D_
    if (dims[1] === undefined) {_x000D_
      return Array(dims[0]);_x000D_
    }_x000D_
_x000D_
    arr = Array(dims[0]);_x000D_
_x000D_
    for (var i = 0; i < dims[0]; i++) {_x000D_
      arr[i] = Array(dims[1]);_x000D_
      arr[i] = makeArray(dims.slice(1), arr[i]);_x000D_
    }_x000D_
_x000D_
    return arr;_x000D_
  }_x000D_
  return makeArray([r, c]);_x000D_
}_x000D_
_x000D_
function G(r) {_x000D_
  var a = [];_x000D_
  while (a.push([]) < r);_x000D_
  return a;_x000D_
}_x000D_
_x000D_
function H(r,c) {_x000D_
  function createArray(length) {_x000D_
    var arr = new Array(length || 0),_x000D_
        i = length;_x000D_
_x000D_
    if (arguments.length > 1) {_x000D_
        var args = Array.prototype.slice.call(arguments, 1);_x000D_
        while(i--) arr[length-1 - i] = createArray.apply(this, args);_x000D_
    }_x000D_
_x000D_
    return arr;_x000D_
  }_x000D_
  return createArray(r,c);_x000D_
}_x000D_
_x000D_
function I(r, c) {_x000D_
  return [...Array(r)].map(x => Array(c));_x000D_
}_x000D_
_x000D_
function J(r, c) {_x000D_
  return Array(r).fill(0).map(() => Array(c));_x000D_
}_x000D_
_x000D_
function K(r, c) {_x000D_
  return Array.from(Array(r), () => Array(c));_x000D_
}_x000D_
_x000D_
function L(r, c) {_x000D_
  return Array.from({length: r}).map(e => Array(c));_x000D_
}_x000D_
_x000D_
function M(r, c) {_x000D_
  return Array.from({length: r}, () => Array.from({length: c}, () => {}));_x000D_
}_x000D_
_x000D_
function N(r, c) {_x000D_
  return {}_x000D_
}_x000D_
_x000D_
_x000D_
_x000D_
// -----------------------------------------------_x000D_
// SHOW_x000D_
// -----------------------------------------------_x000D_
_x000D_
log = (t, f) => {_x000D_
  let A = f(3, 4); // create array with 3 rows and 4 columns_x000D_
  A[1][2] = 6 // 2-nd row 3nd column set to 6_x000D_
  console.log(`${t}[1][2]: ${A[1][2]}, full: ${JSON.stringify(A).replace(/null/g,'x')}`);_x000D_
}_x000D_
_x000D_
log2 = (t, f) => {_x000D_
  let A = f(3, 4); // create array with 3 rows and 4 columns_x000D_
  A[[1,2]] = 6 // 2-nd row 3nd column set to 6_x000D_
  console.log(`${t}[1][2]: ${A[[1,2]]}, full: ${JSON.stringify(A).replace(/null/g,'x')}`);_x000D_
}_x000D_
_x000D_
log('A', A);_x000D_
log('B', B);_x000D_
log('C', C);_x000D_
log('D', D);_x000D_
log('E', E);_x000D_
log('F', F);_x000D_
log('G', G);_x000D_
log('H', H);_x000D_
log('I', I);_x000D_
log('J', J);_x000D_
log('K', K);_x000D_
log('L', L);_x000D_
log('M', M);_x000D_
log2('N', N);
_x000D_ 
This is presentation of solutions - not benchmark
_x000D_
_x000D_
_x000D_

Test for solutions which fill (initialise) output array

We test speed of solutions for

  • small arrays (12 elements) - you can perform tests on your machine HERE
  • big arrays (1 million elements) arrays - you can perform tests on your machine HERE

_x000D_
_x000D_ 
function A(r, c, def) {_x000D_
  var arr = [];_x000D_
  for (var i = 0; i < r; i++) arr[i] = Array(c).fill(def);_x000D_
  return arr;_x000D_
}_x000D_
_x000D_
function B(r, c, def) {_x000D_
  var arr = new Array(r);_x000D_
  for (var i = 0; i < arr.length; i++) arr[i] = new Array(c).fill(def);_x000D_
  return arr;_x000D_
}_x000D_
_x000D_
function C(r, c, def) {_x000D_
  var arr = Array(r);_x000D_
  for (var i = 0; i < arr.length; i++) arr[i] = Array(c).fill(def);_x000D_
  return arr;_x000D_
}_x000D_
_x000D_
function D(r, c, def) {_x000D_
  // strange, but works_x000D_
  var arr = [];_x000D_
  for (var i = 0; i < r; i++) {_x000D_
    arr.push([]);_x000D_
    arr[i].push(Array(c));_x000D_
  }_x000D_
  for (var i = 0; i < r; i++) for (var j = 0; j < c; j++) arr[i][j]=def_x000D_
  return arr;_x000D_
}_x000D_
_x000D_
function E(r, c, def) {_x000D_
  let array = [[]];_x000D_
  for (var x = 0; x < c; x++) {_x000D_
    array[x] = [];_x000D_
    for (var y = 0; y < r; y++) array[x][y] = def;_x000D_
  }_x000D_
  return array;_x000D_
}_x000D_
_x000D_
function F(r, c, def) {_x000D_
  var makeArray = function(dims, arr) {_x000D_
    if (dims[1] === undefined) {_x000D_
      return Array(dims[0]).fill(def);_x000D_
    }_x000D_
_x000D_
    arr = Array(dims[0]);_x000D_
_x000D_
    for (var i = 0; i < dims[0]; i++) {_x000D_
      arr[i] = Array(dims[1]);_x000D_
      arr[i] = makeArray(dims.slice(1), arr[i]);_x000D_
    }_x000D_
_x000D_
    return arr;_x000D_
  }_x000D_
  return makeArray([r, c]);_x000D_
}_x000D_
_x000D_
function G(r, c, def) {_x000D_
  var a = [];_x000D_
  while (a.push(Array(c).fill(def)) < r);_x000D_
  return a;_x000D_
}_x000D_
_x000D_
function H(r,c, def) {_x000D_
  function createArray(length) {_x000D_
    var arr = new Array(length || 0),_x000D_
        i = length;_x000D_
_x000D_
    if (arguments.length > 1) {_x000D_
        var args = Array.prototype.slice.call(arguments, 1);_x000D_
        while(i--) arr[length-1 - i] = createArray.apply(this, args).fill(def);_x000D_
    }_x000D_
_x000D_
    return arr;_x000D_
  }_x000D_
  return createArray(r,c);_x000D_
}_x000D_
_x000D_
function I(r, c, def) {_x000D_
  return [...Array(r)].map(x => Array(c).fill(def));_x000D_
}_x000D_
_x000D_
function J(r, c, def) {_x000D_
  return Array(r).fill(0).map(() => Array(c).fill(def));_x000D_
}_x000D_
_x000D_
function K(r, c, def) {_x000D_
  return Array.from(Array(r), () => Array(c).fill(def));_x000D_
}_x000D_
_x000D_
function L(r, c, def) {_x000D_
  return Array.from({length: r}).map(e => Array(c).fill(def));_x000D_
}_x000D_
_x000D_
function M(r, c, def) {_x000D_
  return Array.from({length: r}, () => Array.from({length: c}, () => def));_x000D_
}_x000D_
_x000D_
function N(r, c, def) {_x000D_
  let arr={};_x000D_
  for (var i = 0; i < r; i++) for (var j = 0; j < c; j++) arr[[i,j]]=def;_x000D_
  return arr;_x000D_
}_x000D_
_x000D_
_x000D_
_x000D_
// -----------------------------------------------_x000D_
// SHOW_x000D_
// -----------------------------------------------_x000D_
_x000D_
log = (t, f) => {_x000D_
  let A = f(1000,1000,7); // create array with 1000 rows and 1000 columns, _x000D_
                          // each array cell initilised by 7_x000D_
  A[800][900] = 5         // 800nd row and 901nd column set to 5_x000D_
  console.log(`${t}[1][2]: ${A[1][2]}, ${t}[800][901]: ${A[800][900]}`);_x000D_
}_x000D_
_x000D_
log2 = (t, f) => {_x000D_
  let A = f(1000,1000,7); // create array with 1000 rows and 1000 columns, _x000D_
                          // each array cell initilised by 7_x000D_
  A[[800,900]] = 5            // 800nd row 900nd column set to 5_x000D_
  console.log(`${t}[1][2]: ${A[[1,2]]}, ${t}[800][900]: ${A[[800,900]]}`);_x000D_
}_x000D_
_x000D_
log('A', A);_x000D_
log('B', B);_x000D_
log('C', C);_x000D_
log('D', D);_x000D_
log('E', E);_x000D_
log('F', F);_x000D_
log('G', G);_x000D_
log('H', H);_x000D_
log('I', I);_x000D_
log('J', J);_x000D_
log('K', K);_x000D_
log('L', L);_x000D_
log('M', M);_x000D_
log2('N', N);
_x000D_ 
This is presentation of solutions - not benchmark
_x000D_
_x000D_
_x000D_

enter image description here

What is %timeit in python?

Line magics are prefixed with the % character and work much like OS command-line calls: they get as an argument the rest of the line, where arguments are passed without parentheses or quotes. Cell magics are prefixed with a double %%, and they are functions that get as an argument not only the rest of the line, but also the lines below it in a separate argument.

sqlite3.ProgrammingError: Incorrect number of bindings supplied. The current statement uses 1, and there are 74 supplied

 
cursor.execute(sql,array)

Only takes two arguments.
It will iterate the "array"-object and match ? in the sql-string.
(with sanity checks to avoid sql-injection)

Does Notepad++ show all hidden characters?

In newer versions of Notepad++ (currently 5.9), this option is under:

View->Show Symbol->Show All Characters

or

View->Show Symbol->Show White Space and Tab

How to extract the substring between two markers?

In python, extracting substring form string can be done using findall method in regular expression (re) module.

>>> import re
>>> s = 'gfgfdAAA1234ZZZuijjk'
>>> ss = re.findall('AAA(.+)ZZZ', s)
>>> print ss
['1234']

Export table from database to csv file

Here is an option I found to export to Excel (can be modified for CSV I believe)

insert into OPENROWSET('Microsoft.Jet.OLEDB.4.0', 
'Excel 8.0;Database=D:\testing.xls;', 
'SELECT * FROM [SheetName$]') select * from SQLServerTable

JavaScript moving element in the DOM

.before and .after

Use modern vanilla JS! Way better/cleaner than previously. No need to reference a parent.

const div1 = document.getElementById("div1");
const div2 = document.getElementById("div2");
const div3 = document.getElementById("div3");

div2.after(div1);
div2.before(div3);

Browser Support - 95% Global as of Oct '20

What's the difference between git reset --mixed, --soft, and --hard?

Three types of regret

A lot of the existing answers don't seem to answer the actual question. They are about what the commands do, not about what you (the user) want — the use case. But that is what the OP asked about!

It might be more helpful to couch the description in terms of what it is precisely that you regret at the time you give a git reset command. Let's say we have this:

A - B - C - D <- HEAD

Here are some possible regrets and what to do about them:

1. I regret that B, C, and D are not one commit.

git reset --soft A. I can now immediately commit and presto, all the changes since A are one commit.

2. I regret that B, C, and D are not ten commits.

git reset --mixed A. The commits are gone and the index is back at A, but the work area still looks as it did after D. So now I can add-and-commit in a whole different grouping.

3. I regret that B, C, and D happened on this branch; I wish I had branched after A and they had happened on that other branch.

Make a new branch otherbranch, and then git reset --hard A. The current branch now ends at A, with otherbranch stemming from it.

(Of course you could also use a hard reset because you wish B, C, and D had never happened at all.)

What is LDAP used for?

LDAP is also used to store your credentials in a network security system and retrieve it with your password and decrypted key giving you access to the services.

MySql sum elements of a column

 
select
  sum(a) as atotal,
  sum(b) as btotal,
  sum(c) as ctotal
from
  yourtable t
where
  t.id in (1, 2, 3)

Pushing value of Var into an Array

Perhaps $('#fruit').val(); is not returning an array and you need something like:

$("#fruit").val() || []

http://docs.jquery.com/Attributes/val

How to find count of Null and Nan values for each column in a PySpark dataframe efficiently?

You can use method shown here and replace isNull with isnan:

from pyspark.sql.functions import isnan, when, count, col

df.select([count(when(isnan(c), c)).alias(c) for c in df.columns]).show()
+-------+----------+---+
|session|timestamp1|id2|
+-------+----------+---+
|      0|         0|  3|
+-------+----------+---+

or

df.select([count(when(isnan(c) | col(c).isNull(), c)).alias(c) for c in df.columns]).show()
+-------+----------+---+
|session|timestamp1|id2|
+-------+----------+---+
|      0|         0|  5|
+-------+----------+---+

Calculating Page Table Size

Since the Logical Address space is 32-bit long that means program size is 2^32 bytes i.e. 4GB. Now we have the page size of 4KB i.e.2^12 bytes.Thus the number of pages in program are 2^20.(no. of pages in program = program size/page size).Now the size of page table entry is 4 byte hence the size of page table is 2^20*4 = 4MB(size of page table = no. of pages in program * page table entry size). Hence 4MB space is required in Memory to store the page table.

day of the week to day number (Monday = 1, Tuesday = 2)

 
$day_number = date('N', $date);

This will return a 1 for Monday to 7 for Sunday, for the date that is stored in $date. Omitting the second argument will cause date() to return the number for the current day.

How to get a Color from hexadecimal Color String

In Xamarin Use this

Control.SetBackgroundColor(global::Android.Graphics.Color.ParseColor("#F5F1F1"));

Is there a common Java utility to break a list into batches?

Similar to OP without streams and libs, but conciser:

public <T> List<List<T>> getBatches(List<T> collection, int batchSize) {
    List<List<T>> batches = new ArrayList<>();
    for (int i = 0; i < collection.size(); i += batchSize) {
        batches.add(collection.subList(i, Math.min(i + batchSize, collection.size())));
    }
    return batches;
}

How to get the type of a variable in MATLAB?

Another related function is whos. It will list all sorts of information (dimensions, byte size, type) for the variables in a given workspace.

>> a = [0 0 7];
>> whos a
  Name      Size            Bytes  Class     Attributes

  a         1x3                24  double              

>> b = 'James Bond';
>> whos b
  Name      Size            Bytes  Class    Attributes

  b         1x10               20  char

dyld: Library not loaded ... Reason: Image not found

For my framework I was using an Xcode subproject added as a git submodule.

I believe I was getting this error because I was signing the framework with a different signing Team than my main app. (switched teams for app; forgot to switch for framework)

Solution is to not sign within the framework project. Instead, in the main app's Target > General > Frameworks, Libraries, and Embedded Content section, sign the framework via Embed & Sign.

If I select Do not Embed or Embed Without Signing I instead get the error:

FRAMEWORK not valid for use in process using Library Validation: mapped file has no cdhash, completely unsigned? Code has to be at least ad-hoc signed.

Oracle - What TNS Names file am I using?

By default, tnsnames.ora is located in the $ORACLE_HOME/network/admin directory on UNIX operating systems and in the ORACLE_HOME\network\admin directory on Windows operating systems. tnsnames.ora can also be stored the following locations:

The directory specified by the TNS_ADMIN environment variable (or registry value)

On UNIX operating systems, the global configuration directory. For example, on the Solaris Operating System, this directory is /var/opt/oracle

If you have multiple ORACLE_HOMES, be aware of which one you are using, as the location of the tnsnames.ora file can vary from one ORACLE_HOME to the next.

For the person who mentioned the TWO_TASK environment variable, that is used to set a default database service name to connect to (which could be a database on another server). The service name you set TWO_TASK to is then looked up in the tnsnames.ora file when you connect.

Configuration with name 'default' not found. Android Studio

For one, it doesn't do good to have more than one settings.gradle file -- it only looks at the top-level one.

When you get this "Configuration with name 'default' not found" error, it's really confusing, but what it means is that Gradle is looking for a module (or a build.gradle) file someplace, and it's not finding it. In your case, you have this in your settings.gradle file:

include ':libraries:Android-Bootstrap',':Android-Bootstrap'

which is making Gradle look for a library at FTPBackup/libraries/Android-Bootstrap. If you're on a case-sensitive filesystem (and you haven't mistyped Libraries in your question when you meant libraries), it may not find FTPBackup/Libraries/Android-Bootstrap because of the case difference. It's also looking for another library at FTPBackup/Android-Bootstrap, and it's definitely not going to find one because that directory isn't there.

This should work:

include ':Libraries:Android-Bootstrap'

You need the same case-sensitive spec in your dependencies block:

compile project (':Libraries:Android-Bootstrap')

How to clear memory to prevent "out of memory error" in excel vba?

Answer is you can't explicitly but you should be freeing memory in your routines.

Some tips though to help memory

  • Make sure you set object to null before exiting your routine.
  • Ensure you call Close on objects if they require it.
  • Don't use global variables unless absolutely necessary

I would recommend checking the memory usage after performing the routine again and again you may have a memory leak.

How to run JUnit tests with Gradle?

How do I add a junit 4 dependency correctly?

Assuming you're resolving against a standard Maven (or equivalent) repo:

dependencies {
    ...
    testCompile "junit:junit:4.11"  // Or whatever version
}

Run those tests in the folders of tests/model?

You define your test source set the same way:

sourceSets {
    ...

    test {
        java {
            srcDirs = ["test/model"]  // Note @Peter's comment below
        }
    }
}

Then invoke the tests as:

./gradlew test

EDIT: If you are using JUnit 5 instead, there are more steps to complete, you should follow this tutorial.

Eclipse change project files location

Much more simple: Right click -> Refactor -> Move.

Importing project into Netbeans

If there is already a nbproject folder it means you can open it straight ahead without importing it as a project with existing sources (ctrl+shift+o) or (cmd+shift+o)

Python Request Post with param data

params is for GET-style URL parameters, data is for POST-style body information. It is perfectly legal to provide both types of information in a request, and your request does so too, but you encoded the URL parameters into the URL already.

Your raw post contains JSON data though. requests can handle JSON encoding for you, and it'll set the correct Content-Type header too; all you need to do is pass in the Python object to be encoded as JSON into the json keyword argument.

You could split out the URL parameters as well:

params = {'sessionKey': '9ebbd0b25760557393a43064a92bae539d962103', 'format': 'xml', 'platformId': 1}

then post your data with:

import requests

url = 'http://192.168.3.45:8080/api/v2/event/log'

data = {"eventType": "AAS_PORTAL_START", "data": {"uid": "hfe3hf45huf33545", "aid": "1", "vid": "1"}}
params = {'sessionKey': '9ebbd0b25760557393a43064a92bae539d962103', 'format': 'xml', 'platformId': 1}

requests.post(url, params=params, json=data)

The json keyword is new in requests version 2.4.2; if you still have to use an older version, encode the JSON manually using the json module and post the encoded result as the data key; you will have to explicitly set the Content-Type header in that case:

import requests
import json

headers = {'content-type': 'application/json'}
url = 'http://192.168.3.45:8080/api/v2/event/log'

data = {"eventType": "AAS_PORTAL_START", "data": {"uid": "hfe3hf45huf33545", "aid": "1", "vid": "1"}}
params = {'sessionKey': '9ebbd0b25760557393a43064a92bae539d962103', 'format': 'xml', 'platformId': 1}

requests.post(url, params=params, data=json.dumps(data), headers=headers)

Specify the date format in XMLGregorianCalendar

There isn’t really an ideal conversion, but I would like to supply a couple of options.

java.time

First, you should use LocalDate from java.time, the modern Java date and time API, for parsing and holding your date. Avoid Date and SimpleDateFormat since they have design problems and also are long outdated. The latter in particular is notoriously troublesome.

    DateTimeFormatter originalDateFormatter = DateTimeFormatter.ofPattern("dd/MM/uuuu");

    String dateString = "13/06/1983";
    LocalDate date = LocalDate.parse(dateString, originalDateFormatter);
    System.out.println(date);

The output is:

1983-06-13

Do you need to go any further? LocalDate.toString() produces the format you asked about.

Format and parse

Assuming that you do require an XMLGregorianCalendar the first and easy option for converting is:

    XMLGregorianCalendar xmlDate = DatatypeFactory.newInstance()
            .newXMLGregorianCalendar(date.toString());
    System.out.println(xmlDate);

1983-06-13

Formatting to a string and parsing it back feels like a waste to me, but as I said, it’s easy and I don’t think that there are any surprises about the result being as expected.

Pass year, month and day of month individually

    XMLGregorianCalendar xmlDate = DatatypeFactory.newInstance()
            .newXMLGregorianCalendarDate(date.getYear(), date.getMonthValue(),
                    date.getDayOfMonth(), DatatypeConstants.FIELD_UNDEFINED);

The result is the same as before. We need to make explicit that we don’t want a time zone offset (this is what DatatypeConstants.FIELD_UNDEFINED specifies). In case someone is wondering, both LocalDate and XMLGregorianCalendar number months the way humans do, so there is no adding or subtracting 1.

Convert through GregorianCalendar

I only show you this option because I somehow consider it the official way: convert LocalDate to ZonedDateTime, then to GregorianCalendar and finally to XMLGregorianCalendar.

    ZonedDateTime dateTime = date.atStartOfDay(ZoneOffset.UTC);
    GregorianCalendar gregCal = GregorianCalendar.from(dateTime);
    XMLGregorianCalendar xmlDate = DatatypeFactory.newInstance()
            .newXMLGregorianCalendar(gregCal);
    xmlDate.setTime(DatatypeConstants.FIELD_UNDEFINED, DatatypeConstants.FIELD_UNDEFINED,
            DatatypeConstants.FIELD_UNDEFINED, DatatypeConstants.FIELD_UNDEFINED);
    xmlDate.setTimezone(DatatypeConstants.FIELD_UNDEFINED);

I like the conversion itself since we neither need to use strings nor need to pass individual fields (with care to do it in the right order). What I don’t like is that we have to pass a time of day and a time zone offset and then wipe out those fields manually afterwards.

Loaded nib but the 'view' outlet was not set

For me, the problem was caused by calling initWithNibName:bundle:. I am using table view cells from a nib file to define entry forms that sit on tableViews. As I don't have a view, doesn't make sense to hook to one. Instead, if I call the initWithStyle: method instead, and from within there, I load the nib file, then things work as expected.

Get my phone number in android

 
private String getMyPhoneNumber(){
    TelephonyManager mTelephonyMgr;
    mTelephonyMgr = (TelephonyManager)
        getSystemService(Context.TELEPHONY_SERVICE); 
    return mTelephonyMgr.getLine1Number();
}

private String getMy10DigitPhoneNumber(){
    String s = getMyPhoneNumber();
    return s.substring(2);
}

How to List All Redis Databases?

Or you can just run the following command and you will see all databases of the Redis instance without firing up redis-cli:

$ redis-cli INFO | grep ^db
db0:keys=1500,expires=2
db1:keys=200000,expires=1
db2:keys=350003,expires=1

How to ensure that there is a delay before a service is started in systemd?

The systemd way to do this is to have the process "talk back" when it's setup somehow, like by opening a socket or sending a notification (or a parent script exiting). Which is of course not always straight-forward especially with third party stuff :|

You might be able to do something inline like

ExecStart=/bin/bash -c '/bin/start_cassandra &; do_bash_loop_waiting_for_it_to_come_up_here'

or a script that does the same. Or put do_bash_loop_waiting_for_it_to_come_up_here in an ExecStartPost

Or create a helper .service that waits for it to come up, so the helper service depends on cassandra, and waits for it to come up, then your other process can depend on the helper service.

(May want to increase TimeoutStartSec from the default 90s as well)

Disabling enter key for form

Here's a simple way to accomplish this with jQuery that limits it to the appropriate input elements:

//prevent submission of forms when pressing Enter key in a text input
$(document).on('keypress', ':input:not(textarea):not([type=submit])', function (e) {
    if (e.which == 13) e.preventDefault();
});

Thanks to this answer: https://stackoverflow.com/a/1977126/560114.

Explode PHP string by new line

Not perfect but I think it must be safest. Add nl2br:

$skuList = explode('<br />', nl2br($_POST['skuList']));

Watching variables contents in Eclipse IDE

You can do so by these ways.

Add watchpoint and while debugging you can see variable in debugger window perspective under variable tab. OR Add System.out.println("variable = " + variable); and see in console.

Filter array to have unique values

As of June 15, 2015 you may use Set() to create a unique array:

var uniqueArray = [...new Set(array)]

For your Example:

var data = ["X_row7", "X_row4", "X_row6", "X_row10", "X_row8", "X_row9", "X_row11", "X_row7", "X_row4", "X_row6", "X_row10", "X_row8", "X_row9", "X_row11", "X_row7", "X_row4", "X_row6", "X_row10", "X_row8", "X_row9", "X_row11", "X_row7", "X_row4", "X_row6", "X_row10", "X_row8", "X_row9", "X_row11", "X_row7", "X_row4", "X_row6", "X_row10", "X_row8", "X_row9", "X_row11", "X_row7", "X_row4", "X_row6", "X_row10", "X_row8", "X_row9", "X_row11"]
var newArray = [...new Set(data)]
console.log(newArray)

>> ["X_row7", "X_row4", "X_row6", "X_row10", "X_row8", "X_row9", "X_row11"]

dyld: Library not loaded: /usr/local/lib/libpng16.16.dylib with anything php related

Just in case someone else runs into this problem I solved it by the following

brew update && brew upgrade # installs libpng 1.6

This caused an error with other packages requiring 1.5 which they were built with, so I linked it:

cd /usr/local/lib/
ln -s ../Cellar/libpng/1.5.18/lib/libpng15.15.dylib

Now they are both living in harmony and side by side for the different packages. It would be better to rebuild the packages that depend on 1.5, but this works as a quick bandage fix.

Android: Clear Activity Stack

When you call startActivity on the last activity you could always use

Intent.FLAG_ACTIVITY_CLEAR_TOP

as a flag on that intent.

Read more about the flag here.

How to save image in database using C#

You'll want to convert the image to a byte[] in C#, and then you'll have the database column as varbinary(MAX)

After that, it's just like saving any other data type.

How to check sbt version?

From within the sbt shell 

sbt:venkat> about
[info] This is sbt 1.3.3
...

Default Activity not found in Android Studio

I figured it out. I mistakenly added final keyword in activity declaration. Once I removed it everything works!

public  class SplashActivity extends AppCompatActivity {
...
}

No shadow by default on Toolbar?

You can also make it work with RelativeLayout. This reduces layout nesting a little bit ;)

<RelativeLayout
    android:layout_width="match_parent"
    android:layout_height="match_parent">

    <include
        android:id="@+id/toolbar"
        layout="@layout/toolbar" />

    <FrameLayout
        android:id="@+id/container"
        android:layout_width="match_parent"
        android:layout_height="match_parent"
        android:layout_below="@id/toolbar" />

    <View
        android:layout_width="match_parent"
        android:layout_height="5dp"
        android:layout_below="@id/toolbar"
        android:background="@drawable/toolbar_shadow" />
</RelativeLayout>

Update value of a nested dictionary of varying depth

That's a bit to the side but do you really need nested dictionaries? Depending on the problem, sometimes flat dictionary may suffice... and look good at it:

>>> dict1 = {('level1','level2','levelA'): 0}
>>> dict1['level1','level2','levelB'] = 1
>>> update = {('level1','level2','levelB'): 10}
>>> dict1.update(update)
>>> print dict1
{('level1', 'level2', 'levelB'): 10, ('level1', 'level2', 'levelA'): 0}

Android Studio: Drawable Folder: How to put Images for Multiple dpi?

The easiest way I have found to have the proper "directory" structure appear under the drawable folder for my icons is this:

  1. Right click "Drawable"
  2. Click on "New", then "Image Asset"
  3. Change "Asset Type" to "Action Bar and Tab Icons"
  4. For "Foreground" choose "ClipArt"
  5. For "Clipart" click and "Choose" button and pick any icon
  6. For "Resource Name" type in you icon file name

Now the pseudo-directories have been created for you under the Drawable folder in the Android view. Open up the true directories on your file system "main/res/drawable-xxhdpi", "main/res/drawable-xhdpi" and replace the icons in each folder with your own of the proper density.

How to call Stored Procedures with EntityFramework?

Basically you just have to map the procedure to the entity using Stored Procedure Mapping.

Once mapped, you use the regular method for adding an item in EF, and it will use your stored procedure instead.

Please see: This Link for a walkthrough. The result will be adding an entity like so (which will actually use your stored procedure)

using (var ctx = new SchoolDBEntities())
        {
            Student stud = new Student();
            stud.StudentName = "New sp student";
            stud.StandardId = 262;

            ctx.Students.Add(stud);
            ctx.SaveChanges();
        }

Add vertical whitespace using Twitter Bootstrap?

I tried using <div class="control-group"> and it did not change my layout. It did not add vertical space. The solution that worked for me was:

<ol style="visibility:hidden;"></ol>

If that doesn't give you enough vertical space, you can incrementally get more by adding nested <li>&nbsp;</li> tags.

jQuery selector for id starts with specific text

If all your divs start with editDialog as you stated, then you can use the following selector:

$("div[id^='editDialog']")

Or you could use a class selector instead if it's easier for you

<div id="editDialog-0" class="editDialog">...</div>

$(".editDialog")

Copying sets Java

With Java 8 you can use stream and collect to copy the items:

Set<Item> newSet = oldSet.stream().collect(Collectors.toSet());

Or you can collect to an ImmutableSet (if you know that the set should not change):

Set<Item> newSet = oldSet.stream().collect(ImmutableSet.toImmutableSet());

C# "as" cast vs classic cast

using as will return null if not a valid cast which allows you to do other things besides wrapping the cast in a try/catch. I hate classic cast. I always use as cast if i'm not sure. Plus, exceptions are expensive. Null checks are not.

How do you disable the unused variable warnings coming out of gcc in 3rd party code I do not wish to edit?

If you're using gcc and want to disable the warning for selected code, you can use the #pragma compiler directive:

#pragma GCC diagnostic push
#pragma GCC diagnostic ignored "-Wunused-variable"
( your problematic library includes )
#pragma GCC diagnostic pop

For code you control, you may also use __attribute__((unused)) to instruct the compiler that specific variables are not used.

How to increase executionTimeout for a long-running query?

You can set executionTimeout in web.config to support the longer execution time.

executionTimeout specifies the maximum number of seconds that a request is allowed to execute before being automatically shut down by ASP.NET. MSDN

<httpRuntime  executionTimeout = "300" />

This make execution timeout to five minutes.

Optional Int32 attribute.

Specifies the maximum number of seconds that a request is allowed to execute before being automatically shut down by ASP.NET.

This time-out applies only if the debug attribute in the compilation element is False. Therefore, if the debug attribute is True, you do not have to set this attribute to a large value in order to avoid application shutdown while you are debugging. The default is 110 seconds, Reference.

Should a function have only one return statement?

As Kent Beck notes when discussing guard clauses in Implementation Patterns making a routine have a single entry and exit point ...

"was to prevent the confusion possible when jumping into and out of many locations in the same routine. It made good sense when applied to FORTRAN or assembly language programs written with lots of global data where even understanding which statements were executed was hard work ... with small methods and mostly local data, it is needlessly conservative."

I find a function written with guard clauses much easier to follow than one long nested bunch of if then else statements.

Determining the size of an Android view at runtime

Are you calling getWidth() before the view is actually laid out on the screen?

A common mistake made by new Android developers is to use the width and height of a view inside its constructor. When a view’s constructor is called, Android doesn’t know yet how big the view will be, so the sizes are set to zero. The real sizes are calculated during the layout stage, which occurs after construction but before anything is drawn. You can use the onSizeChanged() method to be notified of the values when they are known, or you can use the getWidth() and getHeight() methods later, such as in the onDraw() method.

How to load data to hive from HDFS without removing the source file?

An alternative to 'LOAD DATA' is available in which the data will not be moved from your existing source location to hive data warehouse location.

You can use ALTER TABLE command with 'LOCATION' option. Here is below required command

ALTER TABLE table_name ADD PARTITION (date_col='2017-02-07') LOCATION 'hdfs/path/to/location/'

The only condition here is, the location should be a directory instead of file.

Hope this will solve the problem.

Location of sqlite database on the device

You can also check whether your IDE has a utility like Eclipse's DDMS perspective which allows you to browse through the directory and/or copy files to and from the Emulator or a rooted device.

How can I check if a value is of type Integer?

Try this snippet of code

private static boolean isStringInt(String s){
    Scanner in=new Scanner(s);
    return in.hasNextInt();
}

Cassandra cqlsh - connection refused

Check for correct IP address in the cassandra.yaml file. Majority of times the error is due to incorrect IP address of your system also the username and password too.

After doing so initiate cqlsh by the command :-

cqlsh 10.31.79.1 -u cassandra -p cassandra

Invoking modal window in AngularJS Bootstrap UI using JavaScript

OK, so first of all the http://angular-ui.github.io/bootstrap/ has a <modal> directive and the $dialog service and both of those can be used to open modal windows.

The difference is that with the <modal> directive content of a modal is embedded in a hosting template (one that triggers modal window opening). The $dialog service is far more flexible and allow you to load modal's content from a separate file as well as trigger modal windows from any place in AngularJS code (this being a controller, a service or another directive).

Not sure what you mean exactly by "using JavaScript code" but assuming that you mean any place in AngularJS code the $dialog service is probably a way to go.

It is very easy to use and in its simplest form you could just write:

$dialog.dialog({}).open('modalContent.html');

To illustrate that it can be really triggered by any JavaScript code here is a version that triggers modal with a timer, 3 seconds after a controller was instantiated:

function DialogDemoCtrl($scope, $timeout, $dialog){
  $timeout(function(){
    $dialog.dialog({}).open('modalContent.html');  
  }, 3000);  
}

This can be seen in action in this plunk: http://plnkr.co/edit/u9HHaRlHnko492WDtmRU?p=preview

Finally, here is the full reference documentation to the $dialog service described here: https://github.com/angular-ui/bootstrap/blob/master/src/dialog/README.md

SQL Server datetime LIKE select?

There is a very flaky coverage of the LIKE operator for dates in SQL Server. It only works using American date format. As an example you could try:

... WHERE register_date LIKE 'oct 10 2009%'

I've tested this in SQL Server 2005 and it works, but you'll really need to try different combinations. Odd things I have noticed are:

  • You only seem to get all or nothing for different sub fields within the date, for instance, if you search for 'apr 2%' you only get anything in the 20th's - it omits 2nd's.

  • Using a single underscore '_' to represent a single (wildcard) character does not wholly work, for instance, WHERE mydate LIKE 'oct _ 2010%' will not return all dates before the 10th - it returns nothing at all, in fact!

  • The format is rigid American: 'mmm dd yyyy hh:mm'

I have found it difficult to nail down a process for LIKEing seconds, so if anyone wants to take this a bit further, be my guest!

Hope this helps.

Getting current device language in iOS?

For MonoTouch C# developers use:

NSLocale.PreferredLanguages.FirstOrDefault() ?? "en"

Note: I know this was an iOS question, but as I am a MonoTouch developer, the answer on this page led me in the right direction and I thought I'd share the results.

How can I format bytes a cell in Excel as KB, MB, GB etc?

And, yet another solution, is to use engineering notation. (That's like scientific notation except the exponent is always a multiple of 3.) Right-click on the cell(s) and select Format Cells. Under the Number tab, select Custom. Then in the Type: box, put the following:

##0.00E+00

Then click OK. Instead of K, M, etc, you'll have +3, +6, etc. This will work for positive and negative numbers, as well as positive and negative exponents, -3 is m, -6 is u, etc.

567.00E-06
  5.67E-03
 56.70E-03
567.00E-03
  5.67E+00
 56.70E+00
567.00E+00
  5.67E+03
 56.70E+03
567.00E+03
  5.67E+06

Running a command in a new Mac OS X Terminal window

Here's my awesome script, it creates a new terminal window if needed and switches to the directory Finder is in if Finder is frontmost. It has all the machinery you need to run commands.

on run
    -- Figure out if we want to do the cd (doIt)
    -- Figure out what the path is and quote it (myPath)
    try
        tell application "Finder" to set doIt to frontmost
        set myPath to finder_path()
        if myPath is equal to "" then
            set doIt to false
        else
            set myPath to quote_for_bash(myPath)
        end if
    on error
        set doIt to false
    end try

    -- Figure out if we need to open a window
    -- If Terminal was not running, one will be opened automatically
    tell application "System Events" to set isRunning to (exists process "Terminal")

    tell application "Terminal"
        -- Open a new window
        if isRunning then do script ""
        activate
        -- cd to the path
        if doIt then
            -- We need to delay, terminal ignores the second do script otherwise
            delay 0.3
            do script " cd " & myPath in front window
        end if
    end tell
end run

on finder_path()
    try
        tell application "Finder" to set the source_folder to (folder of the front window) as alias
        set thePath to (POSIX path of the source_folder as string)
    on error -- no open folder windows
        set thePath to ""
    end try

    return thePath
end finder_path

-- This simply quotes all occurrences of ' and puts the whole thing between 's
on quote_for_bash(theString)
    set oldDelims to AppleScript's text item delimiters
    set AppleScript's text item delimiters to "'"
    set the parsedList to every text item of theString
    set AppleScript's text item delimiters to "'\\''"
    set theString to the parsedList as string
    set AppleScript's text item delimiters to oldDelims
    return "'" & theString & "'"
end quote_for_bash

How can I check if a single character appears in a string?

 
String temp = "abcdefghi";
if(temp.indexOf("b")!=-1)
{
   System.out.println("there is 'b' in temp string");
}
else
{
   System.out.println("there is no 'b' in temp string");
}

How to convert a char array back to a string?

Try this:

CharSequence[] charArray = {"a","b","c"};

for (int i = 0; i < charArray.length; i++){
    String str = charArray.toString().join("", charArray[i]);
    System.out.print(str);
}

With CSS, how do I make an image span the full width of the page as a background image?

Background images, ideally, are always done with CSS. All other images are done with html. This will span the whole background of your site. 

body {
  background: url('../images/cat.ong');
  background-size: cover;
  background-position: center;
  background-attachment: fixed;
}

What is the apply function in Scala?

TLDR for people comming from c++

It's just overloaded operator of ( ) parentheses

So in scala:

class X {
   def apply(param1: Int, param2: Int, param3: Int) : Int = {
     // Do something
   }
}

Is same as this in c++:

class X {
   int operator()(int param1, int param2, int param3) {
      // do something
   }
};

Pandas timeseries plot setting x-axis major and minor ticks and labels

Both pandas and matplotlib.dates use matplotlib.units for locating the ticks.

But while matplotlib.dates has convenient ways to set the ticks manually, pandas seems to have the focus on auto formatting so far (you can have a look at the code for date conversion and formatting in pandas).

So for the moment it seems more reasonable to use matplotlib.dates (as mentioned by @BrenBarn in his comment).

import numpy as np
import pandas as pd
import matplotlib.pyplot as plt 
import matplotlib.dates as dates

idx = pd.date_range('2011-05-01', '2011-07-01')
s = pd.Series(np.random.randn(len(idx)), index=idx)

fig, ax = plt.subplots()
ax.plot_date(idx.to_pydatetime(), s, 'v-')
ax.xaxis.set_minor_locator(dates.WeekdayLocator(byweekday=(1),
                                                interval=1))
ax.xaxis.set_minor_formatter(dates.DateFormatter('%d\n%a'))
ax.xaxis.grid(True, which="minor")
ax.yaxis.grid()
ax.xaxis.set_major_locator(dates.MonthLocator())
ax.xaxis.set_major_formatter(dates.DateFormatter('\n\n\n%b\n%Y'))
plt.tight_layout()
plt.show()

pandas_like_date_fomatting

(my locale is German, so that Tuesday [Tue] becomes Dienstag [Di])

What are the differences between numpy arrays and matrices? Which one should I use?

As per the official documents, it's not anymore advisable to use matrix class since it will be removed in the future.

https://numpy.org/doc/stable/reference/generated/numpy.matrix.html

As other answers already state that you can achieve all the operations with NumPy arrays.

How to read fetch(PDO::FETCH_ASSOC);

/* Design Pattern "table-data gateway" */

class Gateway
{
    protected $connection = null;

    public function __construct()
    {
        $this->connection = new PDO("mysql:host=localhost; dbname=db_users", 'root', '');
    }

    public function loadAll()
    {
        $sql = 'SELECT * FROM users';
        $rows = $this->connection->query($sql);

        return $rows;
    }

    public function loadById($id)
    {
        $sql = 'SELECT * FROM users WHERE user_id = ' . (int) $id;
        $result = $this->connection->query($sql);

        return $result->fetch(PDO::FETCH_ASSOC);
        // http://php.net/manual/en/pdostatement.fetch.php //                   
    }
}

/* Print all row with column 'user_id' only */

$gateway  = new Gateway();
$users    = $gateway->loadAll();

$no = 1;
foreach ($users as $key => $value) {
    echo $no . '. ' . $key . ' => ' . $value['user_id'] . '<br />';
    $no++;
}

/* Print user_id = 1 with all column */

$user = $gateway->loadById(1);

$no = 1;
foreach ($user as $key => $value) {
    echo $no . '. ' . $key . ' => ' . $value . '<br />';
    $no++;
}

/* Print user_id = 1 with column 'email and password' */

$user = $gateway->loadById(1);

echo $user['email'];
echo $user['password'];

Correct way to use get_or_create?

Following @Tobu answer and @mipadi comment, in a more pythonic way, if not interested in the created flag, I would use:

customer.source, _ = Source.objects.get_or_create(name="Website")

Minimum and maximum value of z-index?

It depends on the browser (although the latest version of all browsers should max out at 2147483638), as does the browser's reaction when the maximum is exceeded.

http://www.puidokas.com/max-z-index/

What is Mocking?

I would think the use of the TypeMock isolator mocking framework would be TypeMocking.

It is a tool that generates mocks for use in unit tests, without the need to write your code with IoC in mind.

Apache and IIS side by side (both listening to port 80) on windows2003

For people with only one IP address and multiple sites on one server, you can configure IIS to listen on a port other than 80, e.g 8080 by setting the TCP port in the properties of each of its sites (including the default one).

In Apache, enable mod_proxy and mod_proxy_http, then add a catch-all VirtualHost (after all others) so that requests Apache isn't explicitly handling get "forwarded" on to IIS.

<VirtualHost *:80>
    ServerName foo.bar
    ServerAlias *
    ProxyPreserveHost On
    ProxyPass / http://127.0.0.1:8080/
</VirtualHost>

Now you can have Apache serve some sites and IIS serve others, with no visible difference to the user.

Edit: your IIS sites must not include their port number in any URLs within their responses, including headers.

How to source virtualenv activate in a Bash script

When I was learning venv I created a script to remind me how to activate it.

#!/bin/sh
# init_venv.sh
if [ -d "./bin" ];then
  echo "[info] Ctrl+d to deactivate"
  bash -c ". bin/activate; exec /usr/bin/env bash --rcfile <(echo 'PS1=\"(venv)\${PS1}\"') -i"
fi

This has the advantage that it changes the prompt.

Escape Character in SQL Server

 
WHERE username LIKE '%[_]d';            -- @Lasse solution
WHERE username LIKE '%$_d' ESCAPE '$';
WHERE username LIKE '%^_d' ESCAPE '^';

FROM: SQL Server Escape an Underscore

MS-DOS Batch file pause with enter key

pause command is what you looking for. If you looking ONLY the case when enter is hit you can abuse the runas command:

runas /user:# "" >nul 2>&1

the screen will be frozen until enter is hit.What I like more than set/p= is that if you press other buttons than enter they will be not displayed.

How can I make a countdown with NSTimer?

Make Countdown app Xcode 8.1, Swift 3

import UIKit
import Foundation

class ViewController: UIViewController, UITextFieldDelegate {

    var timerCount = 0
    var timerRunning = false

    @IBOutlet weak var timerLabel: UILabel! //ADD Label
    @IBOutlet weak var textField: UITextField! //Add TextField /Enter any number to Countdown

    override func viewDidLoad() {
        super.viewDidLoad()

        //Reset
        timerLabel.text = ""
        if timerCount == 0 {
            timerRunning = false
        }
}

       //Figure out Count method
    func Counting() {
        if timerCount > 0 {
        timerLabel.text = "\(timerCount)"
            timerCount -= 1
        } else {
            timerLabel.text = "GO!"

        }

    }

    //ADD Action Button
    @IBAction func startButton(sender: UIButton) {

        //Figure out timer
        if timerRunning == false {
         _ = Timer.scheduledTimer(timeInterval: 1.0, target: self, selector: #selector(ViewController.Counting), userInfo: nil, repeats: true)
            timerRunning = true
        }

        //unwrap textField and Display result
        if let countebleNumber = Int(textField.text!) {
            timerCount = countebleNumber
            textField.text = "" //Clean Up TextField
        } else {
            timerCount = 3 //Defoult Number to Countdown if TextField is nil
            textField.text = "" //Clean Up TextField
        }

    }

    //Dismiss keyboard
    func keyboardDismiss() {
        textField.resignFirstResponder()
    }

    //ADD Gesture Recignizer to Dismiss keyboard then view tapped
    @IBAction func viewTapped(_ sender: AnyObject) {
        keyboardDismiss()
    }

    //Dismiss keyboard using Return Key (Done) Button
    func textFieldShouldReturn(_ textField: UITextField) -> Bool {
        keyboardDismiss()

        return true
    }

}

https://github.com/nikae/CountDown-

HTML5 Video Autoplay not working correctly

//You might want to add some scripts if your software doesn't support jQuery or giving any reference type error.

//Use above scripts only if the software you are working on doesn't support jQuery.

$(document).ready(function() { //Change the location of your mp3 or any music file. var source = "../Assets/music.mp3"; var audio = new Audio(); audio.src = source; audio.autoplay = true; });

Android - Set text to TextView

In xml use this:

<TextView 
       android:id="@+id/textView"
       android:layout_width="wrap_content"
       android:layout_height="wrap_content"/>

In Activity define the view:

Textview textView=(TextView)findViewById(R.id.textView);
textView.setText(getResources().getString(R.string.txt_hello));

In string file:

<string name="txt_hello">Hello</string>

Output: Hello

Is it possible to use jQuery .on and hover?

(Look at the last edit in this answer if you need to use .on() with elements populated with JavaScript)

Use this for elements that are not populated using JavaScript:

$(".selector").on("mouseover", function () {
    //stuff to do on mouseover
});

.hover() has it's own handler: http://api.jquery.com/hover/

If you want to do multiple things, chain them in the .on() handler like so: 

$(".selector").on({
    mouseenter: function () {
        //stuff to do on mouse enter
    },
    mouseleave: function () {
        //stuff to do on mouse leave
    }
});

According to the answers provided below you can use hover with .on(), but:

Although strongly discouraged for new code, you may see the pseudo-event-name "hover" used as a shorthand for the string "mouseenter mouseleave". It attaches a single event handler for those two events, and the handler must examine event.type to determine whether the event is mouseenter or mouseleave. Do not confuse the "hover" pseudo-event-name with the .hover() method, which accepts one or two functions.

Also, there are no performance advantages to using it and it's more bulky than just using mouseenter or mouseleave. The answer I provided requires less code and is the proper way to achieve something like this.

EDIT

It's been a while since this question was answered and it seems to have gained some traction. The above code still stands, but I did want to add something to my original answer.

While I prefer using mouseenter and mouseleave (helps me understand whats going on in the code) with .on() it is just the same as writing the following with hover()

$(".selector").hover(function () {
    //stuff to do on mouse enter
}, 
function () {
    //stuff to do on mouse leave
});

Since the original question did ask how they could properly use on() with hover(), I thought I would correct the usage of on() and didn't find it necessary to add the hover() code at the time.

EDIT DECEMBER 11, 2012

Some new answers provided below detail how .on() should work if the div in question is populated using JavaScript. For example, let's say you populate a div using jQuery's .load() event, like so:

(function ($) {
    //append div to document body
    $('<div class="selector">Test</div>').appendTo(document.body);
}(jQuery));

The above code for .on() would not stand. Instead, you should modify your code slightly, like this:

$(document).on({
    mouseenter: function () {
        //stuff to do on mouse enter
    },
    mouseleave: function () {
        //stuff to do on mouse leave
    }
}, ".selector"); //pass the element as an argument to .on

This code will work for an element populated with JavaScript after a .load() event has happened. Just change your argument to the appropriate selector.

How to pass complex object to ASP.NET WebApi GET from jQuery ajax call?

After finding this StackOverflow question/answer

Complex type is getting null in a ApiController parameter

the [FromBody] attribute on the controller method needs to be [FromUri] since a GET does not have a body. After this change the "filter" complex object is passed correctly.

Find distance between two points on map using Google Map API V2

In Google Map API V2 You have LatLng objects so you can't use distanceTo (yet).

You can then use the following code considering oldPosition and newPosition are LatLng objects :

// The computed distance is stored in results[0].
//If results has length 2 or greater, the initial bearing is stored in results[1].
//If results has length 3 or greater, the final bearing is stored in results[2].
float[] results = new float[1];
Location.distanceBetween(oldPosition.latitude, oldPosition.longitude,
                newPosition.latitude, newPosition.longitude, results);

For more informations about the Location class see this link

How to validate domain name in PHP?

This is validation of domain name in javascript:

<script>
function frmValidate() {
 var val=document.frmDomin.name.value;
 if (/^[a-zA-Z0-9][a-zA-Z0-9-]{1,61}[a-zA-Z0-9](?:\.[a-zA-Z]{2,})+$/.test(val)){
      alert("Valid Domain Name");
      return true;
 } else {
      alert("Enter Valid Domain Name");
      val.name.focus();
      return false;
 }
}
</script>

What is the difference between resource and endpoint?

Possibly mine isn't a great answer but here goes.

Since working more with truly RESTful web services over HTTP, I've tried to steer people away from using the term endpoint since it has no clear definition, and instead use the language of REST which is resources and resource locations.

To my mind, endpoint is a TCP term. It's conflated with HTTP because part of the URL identifies a listening server.

So resource isn't a newer term, I don't think, I think endpoint was always misappropriated and we're realising that as we're getting our heads around REST as a style of API.

Edit

I blogged about this.

https://medium.com/@lukepuplett/stop-saying-endpoints-92c19e33e819

Switching to a TabBar tab view programmatically?

 
import UIKit

class TabbarViewController: UITabBarController,UITabBarControllerDelegate {

//MARK:- View Life Cycle

override func viewDidLoad() {
    super.viewDidLoad()

}

override func didReceiveMemoryWarning() {
    super.didReceiveMemoryWarning()

}

//Tabbar delegate method
override func tabBar(_ tabBar: UITabBar, didSelect item: UITabBarItem) {
    let yourView = self.viewControllers![self.selectedIndex] as! UINavigationController
    yourView.popToRootViewController(animated:false)
}



}

How to set TLS version on apache HttpClient

If you have a javax.net.ssl.SSLSocket class reference in your code, you can set the enabled TLS protocols by a call to SSLSocket.setEnabledProtocols():

import javax.net.ssl.*;
import java.net.*; 
...
Socket socket = SSLSocketFactory.getDefault().createSocket();
...
if (socket instanceof SSLSocket) {
   // "TLSv1.0" gives IllegalArgumentException in Java 8
   String[] protos = {"TLSv1.2", "TLSv1.1"}
   ((SSLSocket)socket).setEnabledProtocols(protos);
}

Datatables - Setting column width

I would suggest not using pixels for sWidth, instead use percentages. Like below:

   "aoColumnDefs": [
  { "sWidth": "20%", "aTargets": [ 0 ] }, <- start from zero
  { "sWidth": "5%", "aTargets": [ 1 ] },
  { "sWidth": "10%", "aTargets": [ 2 ] },
  { "sWidth": "5%", "aTargets": [ 3 ] },
  { "sWidth": "40%", "aTargets": [ 4 ] },
  { "sWidth": "5%", "aTargets": [ 5 ] },
  { "sWidth": "15%", "aTargets": [ 6 ] }
],
     aoColumns : [
      { "sWidth": "20%"},
      { "sWidth": "5%"},
      { "sWidth": "10%"},
      { "sWidth": "5%"},
      { "sWidth": "40%"},
      { "sWidth": "5%"},
      { "sWidth": "15%"}
    ]
});

Hope it helps.

How to POST JSON data with Python Requests?

Starting with Requests version 2.4.2, you can use the json= parameter (which takes a dictionary) instead of data= (which takes a string) in the call:

>>> import requests
>>> r = requests.post('http://httpbin.org/post', json={"key": "value"})
>>> r.status_code
200
>>> r.json()
{'args': {},
 'data': '{"key": "value"}',
 'files': {},
 'form': {},
 'headers': {'Accept': '*/*',
             'Accept-Encoding': 'gzip, deflate',
             'Connection': 'close',
             'Content-Length': '16',
             'Content-Type': 'application/json',
             'Host': 'httpbin.org',
             'User-Agent': 'python-requests/2.4.3 CPython/3.4.0',
             'X-Request-Id': 'xx-xx-xx'},
 'json': {'key': 'value'},
 'origin': 'x.x.x.x',
 'url': 'http://httpbin.org/post'}

Docker official registry (Docker Hub) URL

You're able to get the current registry-url using docker info:

...
Debug Mode (server): false
Registry: https://index.docker.io/v1/
Labels:
...

That's also the url you may use to run your self hosted-registry:

docker run -d -p 5000:5000 --name registry -e REGISTRY_PROXY_REMOTEURL=https://index.docker.io registry:2

Grep & use it right away:

$ echo $(docker info | grep -oP "(?<=Registry: ).*")
https://index.docker.io/v1/

Min/Max-value validators in asp.net mvc

A complete example of how this could be done. To avoid having to write client-side validation scripts, the existing ValidationType = "range" has been used.

public class MinValueAttribute : ValidationAttribute, IClientValidatable
{
    private readonly double _minValue;

    public MinValueAttribute(double minValue)
    {
        _minValue = minValue;
        ErrorMessage = "Enter a value greater than or equal to " + _minValue;  
    }

    public MinValueAttribute(int minValue)
    {
        _minValue = minValue;
        ErrorMessage = "Enter a value greater than or equal to " + _minValue;
    }

    public override bool IsValid(object value)
    {
        return Convert.ToDouble(value) >= _minValue;
    }

    public IEnumerable<ModelClientValidationRule> GetClientValidationRules(ModelMetadata metadata, ControllerContext context)
    {
        var rule = new ModelClientValidationRule();
        rule.ErrorMessage = ErrorMessage;
        rule.ValidationParameters.Add("min", _minValue);
        rule.ValidationParameters.Add("max", Double.MaxValue);
        rule.ValidationType = "range";
        yield return rule;
    }

}

How to remove Left property when position: absolute?

 
left:auto;

This will default the left back to the browser default.

So if you have your Markup/CSS as:

<div class="myClass"></div>

.myClass
{
  position:absolute;
  left:0;
}

When setting RTL, you could change to:

<div class="myClass rtl"></div>

.myClass
{
  position:absolute;
  left:0;
}
.myClass.rtl
{
  left:auto;
  right:0;
}

Calculating sum of repeated elements in AngularJS ng-repeat

 
**Angular 6: Grand Total**       
 **<h2 align="center">Usage Details Of {{profile$.firstName}}</h2>
        <table align ="center">
          <tr>
            <th>Call Usage</th>
            <th>Data Usage</th>
            <th>SMS Usage</th>
            <th>Total Bill</th>
          </tr>
          <tr>
          <tr *ngFor="let user of bills$">
            <td>{{ user.callUsage}}</td>
            <td>{{ user.dataUsage }}</td>
            <td>{{ user.smsUsage }}</td>
       <td>{{user.callUsage *2 + user.dataUsage *1 + user.smsUsage *1}}</td>
          </tr>


          <tr>
            <th> </th>
            <th>Grand Total</th>
            <th></th>
            <td>{{total( bills$)}}</td>
          </tr>
        </table>**


    **Controller:**
        total(bills) {
            var total = 0;
            bills.forEach(element => {
total = total + (element.callUsage * 2 + element.dataUsage * 1 + element.smsUsage * 1);
            });
            return total;
        }

Java: how to add image to Jlabel?

(If you are using NetBeans IDE) Just create a folder in your project but out side of src folder. Named the folder Images. And then put the image into the Images folder and write code below.

// Import ImageIcon     
ImageIcon iconLogo = new ImageIcon("Images/YourCompanyLogo.png");
// In init() method write this code
jLabelYourCompanyLogo.setIcon(iconLogo);

Now run your program.

Correct way to integrate jQuery plugins in AngularJS

Yes, you are correct. If you are using a jQuery plugin, do not put the code in the controller. Instead create a directive and put the code that you would normally have inside the link function of the directive.

There are a couple of points in the documentation that you could take a look at. You can find them here:
Common Pitfalls

Using controllers correctly

Ensure that when you are referencing the script in your view, you refer it last - after the angularjs library, controllers, services and filters are referenced.

EDIT: Rather than using $(element), you can make use of angular.element(element) when using AngularJS with jQuery

String to Binary in C#

It sounds like you basically want to take an ASCII string, or more preferably, a byte[] (as you can encode your string to a byte[] using your preferred encoding mode) into a string of ones and zeros? i.e. 101010010010100100100101001010010100101001010010101000010111101101010

This will do that for you...

//Formats a byte[] into a binary string (010010010010100101010)
public string Format(byte[] data)
{
    //storage for the resulting string
    string result = string.Empty;
    //iterate through the byte[]
    foreach(byte value in data)
    {
        //storage for the individual byte
        string binarybyte = Convert.ToString(value, 2);
        //if the binarybyte is not 8 characters long, its not a proper result
        while(binarybyte.Length < 8)
        {
            //prepend the value with a 0
            binarybyte = "0" + binarybyte;
        }
        //append the binarybyte to the result
        result += binarybyte;
    }
    //return the result
    return result;
}

Set Date in a single line

Calendar has a set() method that can set the year, month, and day-of-month in one call:

myCal.set( theYear, theMonth, theDay );

Restoring database from .mdf and .ldf files of SQL Server 2008

From a script (one that works):

CREATE DATABASE Northwind
ON ( FILENAME = 'C:\Program Files\Microsoft SQL Server\MSSQL11.SQLEXPRESS\MSSQL\DATA\Northwind.mdf' )
LOG ON ( FILENAME = 'C:\Program Files\Microsoft SQL Server\MSSQL11.SQLEXPRESS\MSSQL\DATA\Northwind_log.ldf')
GO

obviously update the path:

C:\Program Files\Microsoft SQL Server\MSSQL11.SQLEXPRESS\MSSQL\DATA

To where your .mdf and .ldf reside.

Effective way to find any file's Encoding

The following codes are my Powershell codes to determinate if some cpp or h or ml files are encodeding with ISO-8859-1(Latin-1) or UTF-8 without BOM, if neither then suppose it to be GB18030. I am a Chinese working in France and MSVC saves as Latin-1 on french computer and saves as GB on Chinese computer so this helps me avoid encoding problem when do source file exchanges between my system and my colleagues.

The way is simple, if all characters are between x00-x7E, ASCII, UTF-8 and Latin-1 are all the same, but if I read a non ASCII file by UTF-8, we will find the special character ? show up, so try to read with Latin-1. In Latin-1, between \x7F and \xAF is empty, while GB uses full between x00-xFF so if I got any between the two, it's not Latin-1

The code is written in PowerShell, but uses .net so it's easy to be translated into C# or F#

$Utf8NoBomEncoding = New-Object System.Text.UTF8Encoding($False)
foreach($i in Get-ChildItem .\ -Recurse -include *.cpp,*.h, *.ml) {
    $openUTF = New-Object System.IO.StreamReader -ArgumentList ($i, [Text.Encoding]::UTF8)
    $contentUTF = $openUTF.ReadToEnd()
    [regex]$regex = '?'
    $c=$regex.Matches($contentUTF).count
    $openUTF.Close()
    if ($c -ne 0) {
        $openLatin1 = New-Object System.IO.StreamReader -ArgumentList ($i, [Text.Encoding]::GetEncoding('ISO-8859-1'))
        $contentLatin1 = $openLatin1.ReadToEnd()
        $openLatin1.Close()
        [regex]$regex = '[\x7F-\xAF]'
        $c=$regex.Matches($contentLatin1).count
        if ($c -eq 0) {
            [System.IO.File]::WriteAllLines($i, $contentLatin1, $Utf8NoBomEncoding)
            $i.FullName
        } 
        else {
            $openGB = New-Object System.IO.StreamReader -ArgumentList ($i, [Text.Encoding]::GetEncoding('GB18030'))
            $contentGB = $openGB.ReadToEnd()
            $openGB.Close()
            [System.IO.File]::WriteAllLines($i, $contentGB, $Utf8NoBomEncoding)
            $i.FullName
        }
    }
}
Write-Host -NoNewLine 'Press any key to continue...';
$null = $Host.UI.RawUI.ReadKey('NoEcho,IncludeKeyDown');

Read line with Scanner

Try to use r.hasNext() instead of r.hasNextLine():

while(r.hasNext()) {
        scan = r.next();

Scanner vs. BufferedReader
  1. BufferedReader will probably give you better performance (because Scanner is based on InputStreamReader, look sources). ups, for reading from files it uses nio. When I tested nio performance against BufferedReader performance for big files nio shows a bit better performance.
  2. For reading from file try Apache Commons IO.

NUnit vs. MbUnit vs. MSTest vs. xUnit.net

Nunit doesnt work well with mixed-mode projects in C++ so I had to drop it

Replace image src location using CSS

Here is another dirty hack :) 

.application-title > img {
display: none;
}

.application-title::before {
content: url(path/example.jpg);
}

Equivalent of String.format in jQuery

If you're using the validation plugin you can use:

jQuery.validator.format("{0} {1}", "cool", "formatting") = 'cool formatting'

http://docs.jquery.com/Plugins/Validation/jQuery.validator.format#templateargumentargumentN...

How to set time zone in codeigniter?

Placing this date_default_timezone_set('Asia/Kolkata'); on config.php above base url also works

PHP List of Supported Time Zones

application/config/config.php

<?php

defined('BASEPATH') OR exit('No direct script access allowed');

date_default_timezone_set('Asia/Kolkata');

Another way I have found use full is if you wish to set a time zone for each user

Create a MY_Controller.php

create a column in your user table you can name it timezone or any thing you want to. So that way when user selects his time zone it can can be set to his timezone when login.

application/core/MY_Controller.php

<?php

class MY_Controller extends CI_Controller {

    public function __construct() {
        parent::__construct();
        $this->set_timezone();
    }

    public function set_timezone() {
        if ($this->session->userdata('user_id')) {
            $this->db->select('timezone');
            $this->db->from($this->db->dbprefix . 'user');
            $this->db->where('user_id', $this->session->userdata('user_id'));
            $query = $this->db->get();
            if ($query->num_rows() > 0) {
                date_default_timezone_set($query->row()->timezone);
            } else {
                return false;
            }
        }
    }
}

Also to get the list of time zones in php

 $timezones =  DateTimeZone::listIdentifiers(DateTimeZone::ALL);

 foreach ($timezones as $timezone) 
 {
    echo $timezone;
    echo "</br>";
 }

What does on_delete do on Django models?

Reorient your mental model of the functionality of "CASCADE" by thinking of adding a FK to an already existing cascade (i.e. a waterfall). The source of this waterfall is a primary key (PK). Deletes flow down.

So if you define a FK's on_delete as "CASCADE," you're adding this FK's record to a cascade of deletes originating from the PK. The FK's record may participate in this cascade or not ("SET_NULL"). In fact, a record with a FK may even prevent the flow of the deletes! Build a dam with "PROTECT."

Print multiple arguments in Python

There are many ways to print that.

Let's have a look with another example.

a = 10
b = 20
c = a + b

#Normal string concatenation
print("sum of", a , "and" , b , "is" , c) 

#convert variable into str
print("sum of " + str(a) + " and " + str(b) + " is " + str(c)) 

# if you want to print in tuple way
print("Sum of %s and %s is %s: " %(a,b,c))  

#New style string formatting
print("sum of {} and {} is {}".format(a,b,c)) 

#in case you want to use repr()
print("sum of " + repr(a) + " and " + repr(b) + " is " + repr(c))

EDIT :

#New f-string formatting from Python 3.6:
print(f'Sum of {a} and {b} is {c}')

How can I echo the whole content of a .html file in PHP?

If you want to make sure the HTML file doesn't contain any PHP code and will not be executed as PHP, do not use include or require. Simply do:

echo file_get_contents("/path/to/file.html");

how to clear localstorage,sessionStorage and cookies in javascript? and then retrieve?

The standard Web Storage, does not say anything about the restoring any of these. So there won't be any standard way to do it. You have to go through the way the browsers implement these, or find a way to backup these before you delete them.

How can I convert an image into a Base64 string?

You can use the Base64 Android class:

String encodedImage = Base64.encodeToString(byteArrayImage, Base64.DEFAULT);

You'll have to convert your image into a byte array though. Here's an example:

Bitmap bm = BitmapFactory.decodeFile("/path/to/image.jpg");
ByteArrayOutputStream baos = new ByteArrayOutputStream();
bm.compress(Bitmap.CompressFormat.JPEG, 100, baos); // bm is the bitmap object
byte[] b = baos.toByteArray();

* Update *

If you're using an older SDK library (because you want it to work on phones with older versions of the OS) you won't have the Base64 class packaged in (since it just came out in API level 8 AKA version 2.2).

Check this article out for a workaround:

How to base64 encode decode Android

What is the "N+1 selects problem" in ORM (Object-Relational Mapping)?

We moved away from the ORM in Django because of this problem. Basically, if you try and do

for p in person:
    print p.car.colour

The ORM will happily return all people (typically as instances of a Person object), but then it will need to query the car table for each Person.

A simple and very effective approach to this is something I call "fanfolding", which avoids the nonsensical idea that query results from a relational database should map back to the original tables from which the query is composed.

Step 1: Wide select

  select * from people_car_colour; # this is a view or sql function

This will return something like

  p.id | p.name | p.telno | car.id | car.type | car.colour
  -----+--------+---------+--------+----------+-----------
  2    | jones  | 2145    | 77     | ford     | red
  2    | jones  | 2145    | 1012   | toyota   | blue
  16   | ashby  | 124     | 99     | bmw      | yellow

Step 2: Objectify

Suck the results into a generic object creator with an argument to split after the third item. This means that "jones" object won't be made more than once.

Step 3: Render

for p in people:
    print p.car.colour # no more car queries

See this web page for an implementation of fanfolding for python.

When to use throws in a Java method declaration?

The code that you looked at is not ideal. You should either:

  1. Catch the exception and handle it; in which case the throws is unnecesary.

  2. Remove the try/catch; in which case the Exception will be handled by a calling method.

  3. Catch the exception, possibly perform some action and then rethrow the exception (not just the message)

Django: Get list of model fields?

As most of answers are outdated I'll try to update you on Django 2.2 Here posts- your app (posts, blog, shop, etc.)

1) From model link: https://docs.djangoproject.com/en/stable/ref/models/meta/

from posts.model import BlogPost

all_fields = BlogPost._meta.fields
#or
all_fields = BlogPost._meta.get_fields()

Note that:

all_fields=BlogPost._meta.get_fields()

Will also get some relationships, which, for ex: you can not display in a view.
As in my case:

Organisation._meta.fields
(<django.db.models.fields.AutoField: id>, <django.db.models.fields.DateField: created>...

and

Organisation._meta.get_fields()
(<ManyToOneRel: crm.activity>, <django.db.models.fields.AutoField: id>, <django.db.models.fields.DateField: created>...

2) From instance

from posts.model import BlogPost

bp = BlogPost()
all_fields = bp._meta.fields

3) From parent model

Let's suppose that we have Post as the parent model and you want to see all the fields in a list, and have the parent fields to be read-only in Edit mode.

from django.contrib import admin
from posts.model import BlogPost 

@admin.register(BlogPost)
class BlogPost(admin.ModelAdmin):
    all_fields = [f.name for f in Organisation._meta.fields]
    parent_fields = BlogPost.get_deferred_fields(BlogPost)

    list_display = all_fields
    read_only = parent_fields

How to save as a new file and keep working on the original one in Vim?

After save new file press

Ctrl-6

This is shortcut to alternate file

How do I add a custom script to my package.json file that runs a javascript file?

Custom Scripts

npm run-script <custom_script_name>

or

npm run <custom_script_name>

In your example, you would want to run npm run-script script1 or npm run script1.

See https://docs.npmjs.com/cli/run-script

Lifecycle Scripts

Node also allows you to run custom scripts for certain lifecycle events, like after npm install is run. These can be found here.

For example: 

"scripts": {
    "postinstall": "electron-rebuild",
},

This would run electron-rebuild after a npm install command.

HTML5 Video not working in IE 11

Although MP4 is supported in Internet explorer it does matter how you encode the file. Make sure you use BASELINE encoding when rendering the video file. This Fixed my issue with IE11

What is the purpose of the var keyword and when should I use it (or omit it)?

Don't use var!

var was the pre-ES6 way to declare a variable. We are now in the future, and you should be coding as such.

Use const and let

const should be used for 95% of cases. It makes it so the variable reference can't change, thus array, object, and DOM node properties can change and should likely be const.

let should be be used for any variable expecting to be reassigned. This includes within a for loop. If you ever write varName = beyond the initialization, use let.

Both have block level scoping, as expected in most other languages.

Event listener for when element becomes visible?

 
var targetNode = document.getElementById('elementId');
var observer = new MutationObserver(function(){
    if(targetNode.style.display != 'none'){
        // doSomething
    }
});
observer.observe(targetNode, { attributes: true, childList: true });

I might be a little late, but you could just use the MutationObserver to observe any changes on the desired element. If any change occurs, you'll just have to check if the element is displayed.

How to check if directory exists in %PATH%?

I haven't done any batch file programming in a while, but:

echo ;%PATH%; | find /C /I ";<string>;"

should give you 0 if string is not found and 1 or more if it is.

EDIT: Added case-insensitive flag, thanks to Panos.

CSS media query to target only iOS devices

I don't know about targeting iOS as a whole, but to target iOS Safari specifically:

@supports (-webkit-touch-callout: none) {
   /* CSS specific to iOS devices */ 
}

@supports not (-webkit-touch-callout: none) {
   /* CSS for other than iOS devices */ 
}

Apparently as of iOS 13 -webkit-overflow-scrolling no longer responds to @supports, but -webkit-touch-callout still does. Of course that could change in the future...

How can I modify a saved Microsoft Access 2007 or 2010 Import Specification?

Another great option is the free V-Tools addin for Microsoft Access. Among other helpful tools it has a form to edit and save the Import/Export specifications.

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Note: As of version 1.83, there is a bug in enumerating the code pages on Windows 10. (Apparently due to a missing/changed API function in Windows 10) The tools still works great, you just need to comment out a few lines of code or step past it in the debug window.

This has been a real life-saver for me in editing a complex import spec for our online orders.

Advantages of SQL Server 2008 over SQL Server 2005?

SQL 2008 also allows you to disable lock escalation on specific tables. I have found this very useful on small frequently updated tables where locks can escalate causing concurrency issues. In SQL 2005, even with the ROWLOCK hint on delete statements locks can be escalated which can lead to deadlocks. In my testing, an application which I have developed had concurrency issues during small table manipulation due to lock escalation on SQL 2005. In SQL 2008 this problem went away.

It is still important to bear in mind the potential overhead of handling large numbers of row locks, but having the option to stop escalation when you want to is very useful.

jQuery checkbox checked state changed event

Just another solution 

$('.checkbox_class').on('change', function(){ // on change of state
   if(this.checked) // if changed state is "CHECKED"
    {
        // do the magic here
    }
})

How to insert new cell into UITableView in Swift

Use beginUpdates and endUpdates to insert a new cell when the button clicked.

As @vadian said in comment, begin/endUpdates has no effect for a single insert/delete/move operation

First of all, append data in your tableview array

Yourarray.append([labeltext])

Then update your table and insert a new row

// Update Table Data
tblname.beginUpdates()
tblname.insertRowsAtIndexPaths([
NSIndexPath(forRow: Yourarray.count-1, inSection: 0)], withRowAnimation: .Automatic)
tblname.endUpdates()

This inserts cell and doesn't need to reload the whole table but if you get any problem with this, you can also use tableview.reloadData()

Swift 3.0

tableView.beginUpdates()
tableView.insertRows(at: [IndexPath(row: yourArray.count-1, section: 0)], with: .automatic)
tableView.endUpdates()

Objective-C

[self.tblname beginUpdates];
NSArray *arr = [NSArray arrayWithObject:[NSIndexPath indexPathForRow:Yourarray.count-1 inSection:0]];
[self.tblname insertRowsAtIndexPaths:arr withRowAnimation:UITableViewRowAnimationAutomatic];
[self.tblname endUpdates];

Javascript : array.length returns undefined

One option is:

Object.keys(myObject).length

Sadly it not works under older IE versions (under 9).

If you need that compatibility, use the painful version:

var key, count = 0;
for(key in myObject) {
  if(myObject.hasOwnProperty(key)) {
    count++;
  }
}

How to check if all elements of a list matches a condition?

Another way to use itertools.ifilter. This checks truthiness and process (using lambda)

Sample-

for x in itertools.ifilter(lambda x: x[2] == 0, my_list):
    print x