Programs & Examples On #Mapper

The mapper is the first step in map reduce step, a component of a larger scalable, parallel-izable algorithm

Hadoop MapReduce: Strange Result when Storing Previous Value in Memory in a Reduce Class (Java)

It is very inefficient to store all values in memory, so the objects are reused and loaded one at a time. See this other SO question for a good explanation. Summary:

[...] when looping through the Iterable value list, each Object instance is re-used, so it only keeps one instance around at a given time.

Entity Framework Core: A second operation started on this context before a previous operation completed

In my case I was using a lock which does not allow the use of await and does not create compiler warning when you don't await an async.

The problem:

lock (someLockObject) {
    // do stuff
    context.SaveChangesAsync();
}

// some other code somewhere else doing await context.SaveChangesAsync() shortly after the lock gets the concurrency error

The fix: Wait for the async inside the lock by making it blocking with a .Wait()

lock (someLockObject) {
    // do stuff
    context.SaveChangesAsync().Wait();
}

No String-argument constructor/factory method to deserialize from String value ('')

This exception says that you are trying to deserialize the object "Address" from string "\"\"" instead of an object description like "{…}". The deserializer can't find a constructor of Address with String argument. You have to replace "" by {} to avoid this error.

How to convert JSON string into List of Java object?

You can also use Gson for this scenario.

Gson gson = new Gson();
NameList nameList = gson.fromJson(data, NameList.class);

List<Name> list = nameList.getList();

Your NameList class could look like:

class NameList{
 List<Name> list;
 //getter and setter
}

RestClientException: Could not extract response. no suitable HttpMessageConverter found

Other possible solution : I tried to map the result of a restTemplate.getForObject with a private class instance (defined inside of my working class). It did not work, but if I define the object to public, inside its own file, it worked correctly.

Hibernate Error executing DDL via JDBC Statement

I have got this error when trying to create JPA entity with the name "User" (in Postgres) that is reserved. So the way it is resolved is to change the table name by @Table annotation:

@Entity
@Table(name="users")
public class User {..}

Or change the table name manually.

How to parse JSON in Kotlin?

I personally use the Jackson module for Kotlin that you can find here: jackson-module-kotlin.

implementation "com.fasterxml.jackson.module:jackson-module-kotlin:$version"

As an example, here is the code to parse the JSON of the Path of Exile skilltree which is quite heavy (84k lines when formatted) :

Kotlin code:

package util

import com.fasterxml.jackson.databind.DeserializationFeature
import com.fasterxml.jackson.module.kotlin.*
import java.io.File

data class SkillTreeData( val characterData: Map<String, CharacterData>, val groups: Map<String, Group>, val root: Root,
                          val nodes: List<Node>, val extraImages: Map<String, ExtraImage>, val min_x: Double,
                          val min_y: Double, val max_x: Double, val max_y: Double,
                          val assets: Map<String, Map<String, String>>, val constants: Constants, val imageRoot: String,
                          val skillSprites: SkillSprites, val imageZoomLevels: List<Int> )


data class CharacterData( val base_str: Int, val base_dex: Int, val base_int: Int )

data class Group( val x: Double, val y: Double, val oo: Map<String, Boolean>?, val n: List<Int> )

data class Root( val g: Int, val o: Int, val oidx: Int, val sa: Int, val da: Int, val ia: Int, val out: List<Int> )

data class Node( val id: Int, val icon: String, val ks: Boolean, val not: Boolean, val dn: String, val m: Boolean,
                 val isJewelSocket: Boolean, val isMultipleChoice: Boolean, val isMultipleChoiceOption: Boolean,
                 val passivePointsGranted: Int, val flavourText: List<String>?, val ascendancyName: String?,
                 val isAscendancyStart: Boolean?, val reminderText: List<String>?, val spc: List<Int>, val sd: List<String>,
                 val g: Int, val o: Int, val oidx: Int, val sa: Int, val da: Int, val ia: Int, val out: List<Int> )

data class ExtraImage( val x: Double, val y: Double, val image: String )

data class Constants( val classes: Map<String, Int>, val characterAttributes: Map<String, Int>,
                      val PSSCentreInnerRadius: Int )

data class SubSpriteCoords( val x: Int, val y: Int, val w: Int, val h: Int )

data class Sprite( val filename: String, val coords: Map<String, SubSpriteCoords> )

data class SkillSprites( val normalActive: List<Sprite>, val notableActive: List<Sprite>,
                         val keystoneActive: List<Sprite>, val normalInactive: List<Sprite>,
                         val notableInactive: List<Sprite>, val keystoneInactive: List<Sprite>,
                         val mastery: List<Sprite> )

private fun convert( jsonFile: File ) {
    val mapper = jacksonObjectMapper()
    mapper.configure( DeserializationFeature.ACCEPT_EMPTY_ARRAY_AS_NULL_OBJECT, true )

    val skillTreeData = mapper.readValue<SkillTreeData>( jsonFile )
    println("Conversion finished !")
}

fun main( args : Array<String> ) {
    val jsonFile: File = File( """rawSkilltree.json""" )
    convert( jsonFile )

JSON (not-formatted): http://filebin.ca/3B3reNQf3KXJ/rawSkilltree.json

Given your description, I believe it matches your needs.

Deserialize Java 8 LocalDateTime with JacksonMapper

You can implement your JsonSerializer

See:

That your propertie in bean

@JsonProperty("start_date")
@JsonFormat("YYYY-MM-dd HH:mm")
@JsonSerialize(using = DateSerializer.class)
private Date startDate;

That way implement your custom class

public class DateSerializer extends JsonSerializer<Date> implements ContextualSerializer<Date> {

    private final String format;

    private DateSerializer(final String format) {
        this.format = format;
    }

    public DateSerializer() {
        this.format = null;
    }

    @Override
    public void serialize(final Date value, final JsonGenerator jgen, final SerializerProvider provider) throws IOException {
        jgen.writeString(new SimpleDateFormat(format).format(value));
    }

    @Override
    public JsonSerializer<Date> createContextual(final SerializationConfig serializationConfig, final BeanProperty beanProperty) throws JsonMappingException {
        final AnnotatedElement annotated = beanProperty.getMember().getAnnotated();
        return new DateSerializer(annotated.getAnnotation(JsonFormat.class).value());
    }

}

Try this after post result for us.

How to set up Automapper in ASP.NET Core

Step To Use AutoMapper with ASP.NET Core.

Step 1. Installing AutoMapper.Extensions.Microsoft.DependencyInjection from NuGet Package.

enter image description here

Step 2. Create a Folder in Solution to keep Mappings with Name "Mappings".

enter image description here

Step 3. After adding Mapping folder we have added a class with Name "MappingProfile" this name can anything unique and good to understand.

In this class, we are going to Maintain all Mappings.

enter image description here

Step 4. Initializing Mapper in Startup "ConfigureServices"

In Startup Class, we Need to Initialize Profile which we have created and also Register AutoMapper Service.

  Mapper.Initialize(cfg => cfg.AddProfile<MappingProfile>());

  services.AddAutoMapper();

Code Snippet to show ConfigureServices Method where we need to Initialize and Register AutoMapper.

public class Startup
{
    public Startup(IConfiguration configuration)
    {
        Configuration = configuration;
    }

    public IConfiguration Configuration { get; }


    public void ConfigureServices(IServiceCollection services)
    {
        services.Configure<CookiePolicyOptions>(options =>
        {
            // This lambda determines whether user consent for non-essential cookies is needed for a given request.
            options.CheckConsentNeeded = context => true;
            options.MinimumSameSitePolicy = SameSiteMode.None;
        });


        // Start Registering and Initializing AutoMapper

        Mapper.Initialize(cfg => cfg.AddProfile<MappingProfile>());
        services.AddAutoMapper();

        // End Registering and Initializing AutoMapper

        services.AddMvc().SetCompatibilityVersion(CompatibilityVersion.Version_2_1);

    }}

Step 5. Get Output.

To Get Mapped result we need to call AutoMapper.Mapper.Map and pass Proper Destination and Source.

AutoMapper.Mapper.Map<Destination>(source);

CodeSnippet

    [HttpPost]
    public void Post([FromBody] SchemeMasterViewModel schemeMaster)
    {
        if (ModelState.IsValid)
        {
            var mappedresult = AutoMapper.Mapper.Map<SchemeMaster>(schemeMaster);
        }
    }

Elasticsearch : Root mapping definition has unsupported parameters index : not_analyzed

Check your Elastic version.

I had these problem because I was looking at the incorrect version's documentation.

enter image description here

Make the size of a heatmap bigger with seaborn

I do not know how to solve this using code, but I do manually adjust the control panel at the right bottom in the plot figure, and adjust the figure size like:

f, ax = plt.subplots(figsize=(16, 12))

at the meantime until you get a matched size colobar. This worked for me.

Index inside map() function

  • suppose you have an array like

_x000D_
_x000D_
   const arr = [1, 2, 3, 4, 5, 6, 7, 8, 9]
    
    
    arr.map((myArr, index) => {
      console.log(`your index is -> ${index} AND value is ${myArr}`);
    })
_x000D_
_x000D_
_x000D_

> output will be
 index is -> 0 AND value is 1
 index is -> 1 AND value is 2
 index is -> 2 AND value is 3
 index is -> 3 AND value is 4
 index is -> 4 AND value is 5
 index is -> 5 AND value is 6
 index is -> 6 AND value is 7
 index is -> 7 AND value is 8
 index is -> 8 AND value is 9

How to use a client certificate to authenticate and authorize in a Web API

Looking at the source code I also think there must be some issue with the private key.

What it is doing is actually to check if the certificate that is passed is of type X509Certificate2 and if it has the private key.

If it doesn't find the private key it tries to find the certificate in the CurrentUser store and then in the LocalMachine store. If it finds the certificate it checks if the private key is present.

(see source code from class SecureChannnel, method EnsurePrivateKey)

So depending on which file you imported (.cer - without private key or .pfx - with private key) and on which store it might not find the right one and Request.ClientCertificate won't be populated.

You can activate Network Tracing to try to debug this. It will give you output like this:

  • Trying to find a matching certificate in the certificate store
  • Cannot find the certificate in either the LocalMachine store or the CurrentUser store.

java.lang.ClassNotFoundException: com.fasterxml.jackson.annotation.JsonInclude$Value

Even though this answer was too late, I'm adding it because I also went through a horrible time finding answer for the same matter. Only different was, I was struggling with AWS Comprehend Medical API.

At the moment I'm writing this answer, if anyone come across the same issue with any AWS SDKs please downgrade jackson-annotaions or any jackson dependencies to 2.8.* versions. The latest 2.9.* versions does not working properly with AWS SDK for some reason. Anyone have any idea about the reason behind that feel free to comment below.

Just in case if anyone is lazy to google maven repos, I have linked down necessary repos.Check them out!

How to return JSON data from spring Controller using @ResponseBody

I was facing same issue. I did not put @ResponseBody since I was using @RestController. But still I was getting error because I did not put the getter/setter method for the Company class. So after putting the getter/setter my problem was resolved.

How to modify JsonNode in Java?

The @Sharon-Ben-Asher answer is ok.

But in my case, for an array i have to use:

((ArrayNode) jsonNode).add("value");

Attempt to invoke virtual method 'void android.widget.Button.setOnClickListener(android.view.View$OnClickListener)' on a null object reference

i had the same problem and it seems like i didn't initiate the button used with click listener, in other words id didn't te

Deserialize JSON with Jackson into Polymorphic Types - A Complete Example is giving me a compile error

As promised, I'm putting an example for how to use annotations to serialize/deserialize polymorphic objects, I based this example in the Animal class from the tutorial you were reading.

First of all your Animal class with the Json Annotations for the subclasses.

import com.fasterxml.jackson.annotation.JsonIgnoreProperties;
import com.fasterxml.jackson.annotation.JsonSubTypes;
import com.fasterxml.jackson.annotation.JsonTypeInfo;

@JsonIgnoreProperties(ignoreUnknown = true)
@JsonTypeInfo(use = JsonTypeInfo.Id.NAME, include = JsonTypeInfo.As.PROPERTY)
@JsonSubTypes({
    @JsonSubTypes.Type(value = Dog.class, name = "Dog"),

    @JsonSubTypes.Type(value = Cat.class, name = "Cat") }
)
public abstract class Animal {

    private String name;

    public String getName() {
        return name;
    }

    public void setName(String name) {
        this.name = name;
    }

}

Then your subclasses, Dog and Cat.

public class Dog extends Animal {

    private String breed;

    public Dog() {

    }

    public Dog(String name, String breed) {
        setName(name);
        setBreed(breed);
    }

    public String getBreed() {
        return breed;
    }

    public void setBreed(String breed) {
        this.breed = breed;
    }
}

public class Cat extends Animal {

    public String getFavoriteToy() {
        return favoriteToy;
    }

    public Cat() {}

    public Cat(String name, String favoriteToy) {
        setName(name);
        setFavoriteToy(favoriteToy);
    }

    public void setFavoriteToy(String favoriteToy) {
        this.favoriteToy = favoriteToy;
    }

    private String favoriteToy;

}

As you can see, there is nothing special for Cat and Dog, the only one that know about them is the abstract class Animal, so when deserializing, you'll target to Animal and the ObjectMapper will return the actual instance as you can see in the following test:

public class Test {

    public static void main(String[] args) {

        ObjectMapper objectMapper = new ObjectMapper();

        Animal myDog = new Dog("ruffus","english shepherd");

        Animal myCat = new Cat("goya", "mice");

        try {
            String dogJson = objectMapper.writeValueAsString(myDog);

            System.out.println(dogJson);

            Animal deserializedDog = objectMapper.readValue(dogJson, Animal.class);

            System.out.println("Deserialized dogJson Class: " + deserializedDog.getClass().getSimpleName());

            String catJson = objectMapper.writeValueAsString(myCat);

            Animal deseriliazedCat = objectMapper.readValue(catJson, Animal.class);

            System.out.println("Deserialized catJson Class: " + deseriliazedCat.getClass().getSimpleName());



        } catch (Exception e) {
            e.printStackTrace();
        }

    }
}

Output after running the Test class:

{"@type":"Dog","name":"ruffus","breed":"english shepherd"}

Deserialized dogJson Class: Dog

{"@type":"Cat","name":"goya","favoriteToy":"mice"}

Deserialized catJson Class: Cat

Hope this helps,

Jose Luis

How to customise the Jackson JSON mapper implicitly used by Spring Boot?

You can configure property inclusion, and numerous other settings, via application.properties:

spring.jackson.default-property-inclusion=non_null

There's a table in the documentation that lists all of the properties that can be used.

If you want more control, you can also customize Spring Boot's configuration programatically using a Jackson2ObjectMapperBuilderCustomizer bean, as described in the documentation:

The context’s Jackson2ObjectMapperBuilder can be customized by one or more Jackson2ObjectMapperBuilderCustomizer beans. Such customizer beans can be ordered (Boot’s own customizer has an order of 0), letting additional customization be applied both before and after Boot’s customization.

Lastly, if you don't want any of Boot's configuration and want to take complete control over how the ObjectMapper is configured, declare your own Jackson2ObjectMapperBuilder bean:

@Bean
Jackson2ObjectMapperBuilder objectMapperBuilder() {
    Jackson2ObjectMapperBuilder builder = new Jackson2ObjectMapperBuilder();
    // Configure the builder to suit your needs
    return builder;
}

serialize/deserialize java 8 java.time with Jackson JSON mapper

If you are using ObjectMapper class of fasterxml, by default ObjectMapper do not understand the LocalDateTime class, so, you need to add another dependency in your gradle/maven :

compile 'com.fasterxml.jackson.datatype:jackson-datatype-jsr310:2.7.3'

Now you need to register the datatype support offered by this library into you objectmapper object, this can be done by following :

ObjectMapper objectMapper = new ObjectMapper();
objectMapper.findAndRegisterModules();

Now, in your jsonString, you can easily put your java.LocalDateTime field as follows :

{
    "user_id": 1,
    "score": 9,
    "date_time": "2016-05-28T17:39:44.937"
}

By doing all this, your Json file to Java object conversion will work fine, you can read the file by following :

objectMapper.readValue(jsonString, new TypeReference<List<User>>() {
            });

Can not deserialize instance of java.lang.String out of START_ARRAY token

The error is:

Can not deserialize instance of java.lang.String out of START_ARRAY token at [Source: line: 1, column: 1095] (through reference chain: JsonGen["platforms"])

In JSON, platforms look like this:

"platforms": [
    {
        "platform": "iphone"
    },
    {
        "platform": "ipad"
    },
    {
        "platform": "android_phone"
    },
    {
        "platform": "android_tablet"
    }
]

So try change your pojo to something like this:

private List platforms;

public List getPlatforms(){
    return this.platforms;
}

public void setPlatforms(List platforms){
    this.platforms = platforms;
}

EDIT: you will need change mobile_networks too. Will look like this:

private List mobile_networks;

public List getMobile_networks() {
    return mobile_networks;
}

public void setMobile_networks(List mobile_networks) {
    this.mobile_networks = mobile_networks;
}

No content to map due to end-of-input jackson parser

I know this is weird but when I changed GetMapping to PostMapping for both client and server side the error disappeared.

Both client and server are Spring boot projects.

How to analyze disk usage of a Docker container

Posting this as an answer because my comments above got hidden:

List the size of a container:

du -d 2 -h /var/lib/docker/devicemapper | grep `docker inspect -f "{{.Id}}" <container_name>`

List the sizes of a container's volumes:

docker inspect -f "{{.Volumes}}" <container_name> | sed 's/map\[//' | sed 's/]//' | tr ' ' '\n' | sed 's/.*://' | xargs sudo du -d 1 -h

Edit: List all running containers' sizes and volumes:

for d in `docker ps -q`; do
    d_name=`docker inspect -f {{.Name}} $d`
    echo "========================================================="
    echo "$d_name ($d) container size:"
    sudo du -d 2 -h /var/lib/docker/devicemapper | grep `docker inspect -f "{{.Id}}" $d`
    echo "$d_name ($d) volumes:"
    docker inspect -f "{{.Volumes}}" $d | sed 's/map\[//' | sed 's/]//' | tr ' ' '\n' | sed 's/.*://' | xargs sudo du -d 1 -h
done

NOTE: Change 'devicemapper' according to your Docker filesystem (e.g 'aufs')

Resource u'tokenizers/punkt/english.pickle' not found

I was getting an error despite importing the following,

import nltk
nltk.download()

but for google colab this solved my issue.

   !python3 -c "import nltk; nltk.download('all')"

resize2fs: Bad magic number in super-block while trying to open

How to resize root partition online :  

1)  [root@oel7 ~]# df -h  
Filesystem                         Size  Used Avail Use% Mounted on  
/dev/mapper/root_vg-root           5.0G  4.5G  548M  90% /

2)   

PV /dev/sda2   VG root_vg     lvm2 [6.00 GiB / 0    free]

as here it shows that there is no space left on root_vg volume group, so first i need to extend VG 

3)  
[root@oel7 ~]# vgextend root_vg /dev/sdb5  

  Volume group "root_vg" successfully extended

4)  

[root@oel7 ~]# pvscan  
    PV /dev/sda2   VG root_vg     lvm2 [6.00 GiB / 0    free]  
    PV /dev/sdb5   VG root_vg     lvm2 [2.00 GiB / 2.00 GiB free]

5)  Now extend the logical volume   

[root@oel7 ~]# lvextend -L +1G /dev/root_vg/root  

  Size of logical volume root_vg/root changed from 5.00 GiB (1280 extents) to 6.00 GiB (1536 extents).
  Logical volume root successfully resized  

3)  [root@oel7 ~]# resize2fs /dev/root_vg/root  

resize2fs 1.42.9 (28-Dec-2013)  
resize2fs: Bad magic number in super-block while trying to open /dev/root_vg  /root  
Couldn't find valid filesystem superblock.  

as root partition is not a ext* partiton so , you resize2fs will not work for you.  

4)  to check the filesystem type of a partition 
[root@oel7 ~]# df -Th  
Filesystem                        Type      Size  Used Avail Use% Mounted on  
/dev/mapper/root_vg-root          xfs       6.0G  4.5G  1.6G  75% /  
devtmpfs                          devtmpfs  481M     0  481M   0% /dev  
tmpfs                             tmpfs     491M   80K  491M   1% /dev/shm  
tmpfs                             tmpfs     491M  7.1M  484M   2% /run  
tmpfs                             tmpfs     491M     0  491M   0% /sys/fs  /cgroup
/dev/mapper/data_vg-home          xfs       3.5G  2.9G  620M  83% /home  
/dev/sda1                         xfs       497M  132M  365M  27% /boot  
/dev/mapper/data_vg01-data_lv001  ext3      4.0G  2.4G  1.5G  62% /sybase  
/dev/mapper/data_vg02-backup_lv01 ext3      4.0G  806M  3.0G  22% /backup  

above command shows that root is an xfs filesystem , so we are sure that we need to use xfs_growfs command to resize the partition.

6)  [root@oel7 ~]# xfs_growfs /dev/root_vg/root  
meta-data=/dev/mapper/root_vg-root isize=256    agcount=4, agsize=327680 blks
         =                       sectsz=512   attr=2, projid32bit=1
         =                       crc=0        finobt=0
data     =                       bsize=4096   blocks=1310720, imaxpct=25
         =                       sunit=0      swidth=0 blks
naming   =version 2              bsize=4096   ascii-ci=0 ftype=0
log      =internal               bsize=4096   blocks=2560, version=2
         =                       sectsz=512   sunit=0 blks, lazy-count=1
realtime =none                   extsz=4096   blocks=0, rtextents=0
data blocks changed from 1310720 to 1572864  

[root@oel7 ~]# df -Th  

Filesystem                        Type      Size  Used Avail Use% Mounted on
/dev/mapper/root_vg-root          xfs       6.0G  4.5G  1.6G  75% /  

Cannot deserialize instance of object out of START_ARRAY token in Spring Webservice

Taking for granted that the JSON you posted is actually what you are seeing in the browser, then the problem is the JSON itself.

The JSON snippet you have posted is malformed.

You have posted:

[{
        "name" : "shopqwe",
        "mobiles" : [],
        "address" : {
            "town" : "city",
            "street" : "streetqwe",
            "streetNumber" : "59",
            "cordX" : 2.229997,
            "cordY" : 1.002539
        },
        "shoe"[{
                "shoeName" : "addidas",
                "number" : "631744030",
                "producent" : "nike",
                "price" : 999.0,
                "sizes" : [30.0, 35.0, 38.0]
            }]

while the correct JSON would be:

[{
        "name" : "shopqwe",
        "mobiles" : [],
        "address" : {
            "town" : "city",
            "street" : "streetqwe",
            "streetNumber" : "59",
            "cordX" : 2.229997,
            "cordY" : 1.002539
        },
        "shoe" : [{
                "shoeName" : "addidas",
                "number" : "631744030",
                "producent" : "nike",
                "price" : 999.0,
                "sizes" : [30.0, 35.0, 38.0]
            }
        ]
    }
]

Could not read JSON: Can not deserialize instance of hello.Country[] out of START_OBJECT token

In my case, I was getting value of <input type="text"> with JQuery and I did it like this:

var newUserInfo = { "lastName": inputLastName[0].value, "userName": inputUsername[0].value,
 "firstName": inputFirstName[0] , "email": inputEmail[0].value}

And I was constantly getting this exception

com.fasterxml.jackson.databind.JsonMappingException: Can not deserialize instance of java.lang.String out of START_OBJECT token at [Source: java.io.PushbackInputStream@39cb6c98; line: 1, column: 54] (through reference chain: com.springboot.domain.User["firstName"]).

And I banged my head for like an hour until I realised that I forgot to write .value after this"firstName": inputFirstName[0].

So, the correct solution was:

var newUserInfo = { "lastName": inputLastName[0].value, "userName": inputUsername[0].value,
 "firstName": inputFirstName[0].value , "email": inputEmail[0].value}

I came here because I had this problem and I hope I save someone else hours of misery.

Cheers :)

Could not extract response: no suitable HttpMessageConverter found for response type

public class Application {

    private static List<HttpMessageConverter<?>> getMessageConverters() {
        List<HttpMessageConverter<?>> converters = new ArrayList<HttpMessageConverter<?>>();
        converters.add(new MappingJacksonHttpMessageConverter());
        return converters;
    }   

    public static void main(String[] args) {
        RestTemplate restTemplate = new RestTemplate();

        restTemplate.setMessageConverters(getMessageConverters());
        HttpHeaders headers = new HttpHeaders();
        headers.setAccept(Arrays.asList(MediaType.APPLICATION_JSON));
        HttpEntity<String> entity = new HttpEntity<String>(headers);
        //Page page = restTemplate.getForObject("http://graph.facebook.com/pivotalsoftware", Page.class);

        ResponseEntity<Page> response = 
                  restTemplate.exchange("http://graph.facebook.com/skbh86", HttpMethod.GET, entity, Page.class, "1");
        Page page = response.getBody();
        System.out.println("Name:    " + page.getId());
        System.out.println("About:   " + page.getFirst_name());
        System.out.println("Phone:   " + page.getLast_name());
        System.out.println("Website: " + page.getMiddle_name());
        System.out.println("Website: " + page.getName());
    }
}

No space left on device

To list processes holding deleted files a linux system which has no lsof, here's my trick:

    pushd /proc ; for i in [1-9]* ; do ls -l $i/fd | grep "(deleted)" && (echo -n "used by: " ; ps -p $i | grep -v PID ; echo ) ; done ; popd

How to edit Docker container files from the host?

There are two ways to mount files into your container. It looks like you want a bind mount.

Bind Mounts

This mounts local files directly into the container's filesystem. The containerside path and the hostside path both point to the same file. Edits made from either side will show up on both sides.

  • mount the file:
? echo foo > ./foo
? docker run --mount type=bind,source=$(pwd)/foo,target=/foo -it debian:latest
# cat /foo
foo # local file shows up in container
  • in a separate shell, edit the file:
? echo 'bar' > ./foo # make a hostside change
  • back in the container:
# cat /foo
bar # the hostside change shows up
# echo baz > /foo # make a containerside change
# exit
 
? cat foo
baz # the containerside change shows up

Volume Mounts

  • mount the volume
? docker run --mount type=volume,source=foovolume,target=/foo  -it debian:latest
root@containerB# echo 'this is in a volume' > /foo/data
  • the local filesystem is unchanged
  • docker sees a new volume:
? docker volume ls
DRIVER    VOLUME NAME
local     foovolume
  • create a new container with the same volume
? docker run --mount type=volume,source=foovolume,target=/foo  -it debian:latest
root@containerC:/# cat /foo/data
this is in a volume # data is still available

syntax: -v vs --mount

These do the same thing. -v is more concise, --mount is more explicit.

bind mounts

-v /hostside/path:/containerside/path
--mount type=bind,source=/hostside/path,target=/containerside/path

volume mounts

-v /containerside/path
-v volumename:/containerside/path
--mount type=volume,source=volumename,target=/containerside/path

(If a volume name is not specified, a random one is chosen.)

The documentaion tries to convince you to use one thing in favor of another instead of just telling you how it works, which is confusing.

Java 8 Streams FlatMap method example

Made up example

Imagine that you want to create the following sequence: 1, 2, 2, 3, 3, 3, 4, 4, 4, 4 etc. (in other words: 1x1, 2x2, 3x3 etc.)

With flatMap it could look like:

IntStream sequence = IntStream.rangeClosed(1, 4)
                          .flatMap(i -> IntStream.iterate(i, identity()).limit(i));
sequence.forEach(System.out::println);

where:

  • IntStream.rangeClosed(1, 4) creates a stream of int from 1 to 4, inclusive
  • IntStream.iterate(i, identity()).limit(i) creates a stream of length i of int i - so applied to i = 4 it creates a stream: 4, 4, 4, 4
  • flatMap "flattens" the stream and "concatenates" it to the original stream

With Java < 8 you would need two nested loops:

List<Integer> list = new ArrayList<>();
for (int i = 1; i <= 4; i++) {
    for (int j = 0; j < i; j++) {
        list.add(i);
    }
}

Real world example

Let's say I have a List<TimeSeries> where each TimeSeries is essentially a Map<LocalDate, Double>. I want to get a list of all dates for which at least one of the time series has a value. flatMap to the rescue:

list.stream().parallel()
    .flatMap(ts -> ts.dates().stream()) // for each TS, stream dates and flatmap
    .distinct()                         // remove duplicates
    .sorted()                           // sort ascending
    .collect(toList());

Not only is it readable, but if you suddenly need to process 100k elements, simply adding parallel() will improve performance without you writing any concurrent code.

Convert JSONObject to Map

Found out these problems can be addressed by using

ObjectMapper#convertValue(Object fromValue, Class<T> toValueType)

As a result, the origal quuestion can be solved in a 2-step converison:

  1. Demarshall the JSON back to an object - in which the Map<String, Object> is demarshalled as a HashMap<String, LinkedHashMap>, by using bjectMapper#readValue().

  2. Convert inner LinkedHashMaps back to proper objects

ObjectMapper mapper = new ObjectMapper(); Class clazz = (Class) Class.forName(classType); MyOwnObject value = mapper.convertValue(value, clazz);

To prevent the 'classType' has to be known in advance, I enforced during marshalling an extra Map was added, containing <key, classNameString> pairs. So at unmarshalling time, the classType can be extracted dynamically.

Representing null in JSON

I would use null to show that there is no value for that particular key. For example, use null to represent that "number of devices in your household connects to internet" is unknown.

On the other hand, use {} if that particular key is not applicable. For example, you should not show a count, even if null, to the question "number of cars that has active internet connection" is asked to someone who does not own any cars.

I would avoid defaulting any value unless that default makes sense. While you may decide to use null to represent no value, certainly never use "null" to do so.

Container is running beyond memory limits

Running yarn on Windows Linux subsystem with Ubunto OS, error "running beyond virtual memory limits, Killing container" I resolved it by disabling virtual memory check in the file yarn-site.xml

<property> <name>yarn.nodemanager.vmem-check-enabled</name> <value>false</value> </property> 

Convert JsonNode into POJO

If you're using org.codehaus.jackson, this has been possible since 1.6. You can convert a JsonNode to a POJO with ObjectMapper#readValue: http://jackson.codehaus.org/1.9.4/javadoc/org/codehaus/jackson/map/ObjectMapper.html#readValue(org.codehaus.jackson.JsonNode, java.lang.Class)


    ObjectMapper mapper = new ObjectMapper();
    JsonParser jsonParser = mapper.getJsonFactory().createJsonParser("{\"foo\":\"bar\"}");
    JsonNode tree = jsonParser.readValueAsTree();
    // Do stuff to the tree
    mapper.readValue(tree, Foo.class);

JDBC ODBC Driver Connection

As mentioned in the comments to the question, the JDBC-ODBC Bridge is - as the name indicates - only a mechanism for the JDBC layer to "talk to" the ODBC layer. Even if you had a JDBC-ODBC Bridge on your Mac you would also need to have

  • an implementation of ODBC itself, and
  • an appropriate ODBC driver for the target database (ACE/Jet, a.k.a. "Access")

So, for most people, using JDBC-ODBC Bridge technology to manipulate ACE/Jet ("Access") databases is really a practical option only under Windows. It is also important to note that the JDBC-ODBC Bridge will be has been removed in Java 8 (ref: here).

There are other ways of manipulating ACE/Jet databases from Java, such as UCanAccess and Jackcess. Both of these are pure Java implementations so they work on non-Windows platforms. For details on how to use UCanAccess see

Manipulating an Access database from Java without ODBC

Can not deserialize instance of java.lang.String out of START_OBJECT token

You're mapping this JSON

{
    "id": 2,
    "socket": "0c317829-69bf-43d6-b598-7c0c550635bb",
    "type": "getDashboard",
    "data": {
        "workstationUuid": "ddec1caa-a97f-4922-833f-632da07ffc11"
    },
    "reply": true
}

that contains an element named data that has a JSON object as its value. You are trying to deserialize the element named workstationUuid from that JSON object into this setter.

@JsonProperty("workstationUuid")
public void setWorkstation(String workstationUUID) {

This won't work directly because Jackson sees a JSON_OBJECT, not a String.

Try creating a class Data

public class Data { // the name doesn't matter 
    @JsonProperty("workstationUuid")
    private String workstationUuid;
    // getter and setter
}

the switch up your method

@JsonProperty("data")
public void setWorkstation(Data data) {
    // use getter to retrieve it

Issue with parsing the content from json file with Jackson & message- JsonMappingException -Cannot deserialize as out of START_ARRAY token

I sorted this problem as verifying the json from JSONLint.com and then, correcting it. And this is code for the same.

String jsonStr = "[{\r\n" + "\"name\":\"New York\",\r\n" + "\"number\": \"732921\",\r\n"+ "\"center\": {\r\n" + "\"latitude\": 38.895111,\r\n"  + " \"longitude\": -77.036667\r\n" + "}\r\n" + "},\r\n" + " {\r\n"+ "\"name\": \"San Francisco\",\r\n" +\"number\":\"298732\",\r\n"+ "\"center\": {\r\n" + "    \"latitude\": 37.783333,\r\n"+ "\"longitude\": -122.416667\r\n" + "}\r\n" + "}\r\n" + "]";

ObjectMapper mapper = new ObjectMapper();
MyPojo[] jsonObj = mapper.readValue(jsonStr, MyPojo[].class);

for (MyPojo itr : jsonObj) {
    System.out.println("Val of name is: " + itr.getName());
    System.out.println("Val of number is: " + itr.getNumber());
    System.out.println("Val of latitude is: " + 
        itr.getCenter().getLatitude());
    System.out.println("Val of longitude is: " + 
        itr.getCenter().getLongitude() + "\n");
}

Note: MyPojo[].class is the class having getter and setter of json properties.

Result:

Val of name is: New York
Val of number is: 732921
Val of latitude is: 38.895111
Val of longitude is: -77.036667
Val of name is: San Francisco
Val of number is: 298732
Val of latitude is: 37.783333
Val of longitude is: -122.416667

how to convert JSONArray to List of Object using camel-jackson

I also faced the similar problem with JSON output format. This code worked for me with the above JSON format.

package com.test.ameba;

import java.util.List;

public class OutputRanges {
    public List<Range> OutputRanges;
    public String Message;
    public String Entity;

    /**
     * @return the outputRanges
     */
    public List<Range> getOutputRanges() {
        return OutputRanges;
    }

    /**
     * @param outputRanges the outputRanges to set
     */
    public void setOutputRanges(List<Range> outputRanges) {
        OutputRanges = outputRanges;
    }

    /**
     * @return the message
     */
    public String getMessage() {
        return Message;
    }

    /**
     * @param message the message to set
     */
    public void setMessage(String message) {
        Message = message;
    }

    /**
     * @return the entity
     */
    public String getEntity() {
        return Entity;
    }

    /**
     * @param entity the entity to set
     */
    public void setEntity(String entity) {
        Entity = entity;
    }
}

package com.test;


public class Range {
    public String Name;
    /**
     * @return the name
     */
    public String getName() {
        return Name;
    }
    /**
     * @param name the name to set
     */
    public void setName(String name) {
        Name = name;
    }

    public Object[] Value;
    /**
     * @return the value
     */
    public Object[] getValue() {
        return Value;
    }
    /**
     * @param value the value to set
     */
    public void setValue(Object[] value) {
        Value = value;
    }

}

package com.test.ameba;

import java.io.IOException;

import com.fasterxml.jackson.core.JsonParseException;
import com.fasterxml.jackson.databind.JsonMappingException;
import com.fasterxml.jackson.databind.ObjectMapper;

public class JSONTest {

    /**
     * @param args
     */
    public static void main(String[] args) {
        // TODO Auto-generated method stub
        String jsonString ="{\"OutputRanges\":[{\"Name\":\"ABF_MEDICAL_RELATIVITY\",\"Value\":[[1.3628407124839714]]},{\"Name\":\" ABF_RX_RELATIVITY\",\"Value\":[[\"CPD\",\"SL Limit\",\"Concat\",1,1.5,2,2.5,3]]},{\"Name\":\" ABF_Unique_ID_ERR\",\"Value\":[[\"CPD\",\"SL Limit\",\"Concat\",1,1.5,2,2.5,3]]},{\"Name\":\" ABF_FIRST_ERR\",\"Value\":[[\"CPD\",\"SL Limit\",\"Concat\",1,1.5,2,2.5,3]]},{\"Name\":\" ABF_AMEBA_ERR\",\"Value\":[[\"CPD\",\"SL Limit\",\"Concat\",1,1.5,2,2.5,3]]},{\"Name\":\" ABF_Effective_Date_ERR\",\"Value\":[[\"CPD\",\"SL Limit\",\"Concat\",1,1.5,2,2.5,3]]},{\"Name\":\" ABF_AMEBA_MODEL\",\"Value\":[[\"CPD\",\"SL Limit\",\"Concat\",1,1.5,2,2.5,3]]},{\"Name\":\" ABF_UC_ER_COPAY_ERR\",\"Value\":[[\"CPD\",\"SL Limit\",\"Concat\",1,1.5,2,2.5,3]]},{\"Name\":\" ABF_INN_OON_DED_ERR\",\"Value\":[[\"CPD\",\"SL Limit\",\"Concat\",1,1.5,2,2.5,3]]},{\"Name\":\" ABF_COINSURANCE_ERR\",\"Value\":[[\"CPD\",\"SL Limit\",\"Concat\",1,1.5,2,2.5,3]]},{\"Name\":\" ABF_PCP_SPEC_COPAY_ERR\",\"Value\":[[\"CPD\",\"SL Limit\",\"Concat\",1,1.5,2,2.5,3]]},{\"Name\":\" ABF_INN_OON_OOP_MAX_ERR\",\"Value\":[[\"CPD\",\"SL Limit\",\"Concat\",1,1.5,2,2.5,3]]},{\"Name\":\" ABF_IP_OP_COPAY_ERR\",\"Value\":[[\"CPD\",\"SL Limit\",\"Concat\",1,1.5,2,2.5,3]]},{\"Name\":\" ABF_PHARMACY_ERR\",\"Value\":[[\"CPD\",\"SL Limit\",\"Concat\",1,1.5,2,2.5,3]]},{\"Name\":\" ABF_PLAN_ADMIN_ERR\",\"Value\":[[\"CPD\",\"SL Limit\",\"Concat\",1,1.5,2,2.5,3]]}],\"Message\":\"\",\"Entity\":null}";
        ObjectMapper mapper = new ObjectMapper();
        OutputRanges OutputRanges=null;
        try {
            OutputRanges = mapper.readValue(jsonString, OutputRanges.class);
        } catch (JsonParseException e) {
            // TODO Auto-generated catch block
            e.printStackTrace();
        } catch (JsonMappingException e) {
            // TODO Auto-generated catch block
            e.printStackTrace();
        } catch (IOException e) {
            // TODO Auto-generated catch block
            e.printStackTrace();
        }
        System.out.println("OutputRanges :: "+OutputRanges);;
        System.out.println("OutputRanges.getOutputRanges() :: "+OutputRanges.getOutputRanges());;
        for (Range r : OutputRanges.getOutputRanges()) {
            System.out.println(r.getName());
        }
    }

}

Collectors.toMap() keyMapper -- more succinct expression?

List<Person> roster = ...;

Map<String, Person> map = 
    roster
        .stream()
        .collect(
            Collectors.toMap(p -> p.getLast(), p -> p)
        );

that would be the translation, but i havent run this or used the API. most likely you can substitute p -> p, for Function.identity(). and statically import toMap(...)

Correct set of dependencies for using Jackson mapper

No, you can simply use com.fasterxml.jackson.databind.ObjectMapper. Most likely you forgot to fix your import-statements, delete all references to codehaus and you're golden.

What is the best way to get the first letter from a string in Java, returned as a string of length 1?

import org.openjdk.jmh.annotations.Benchmark;
import org.openjdk.jmh.annotations.BenchmarkMode;
import org.openjdk.jmh.annotations.Fork;
import org.openjdk.jmh.annotations.Measurement;
import org.openjdk.jmh.annotations.Mode;
import org.openjdk.jmh.annotations.OutputTimeUnit;
import org.openjdk.jmh.annotations.Scope;
import org.openjdk.jmh.annotations.Setup;
import org.openjdk.jmh.annotations.State;
import org.openjdk.jmh.annotations.Warmup;

import java.util.concurrent.TimeUnit;

@State(Scope.Thread)
@BenchmarkMode(Mode.AverageTime)
@OutputTimeUnit(TimeUnit.NANOSECONDS)
@Warmup(iterations = 5, time = 1)
@Fork(value = 1)
@Measurement(iterations = 5, time = 1)
public class StringFirstCharBenchmark {

    private String source;

    @Setup
    public void init() {
        source = "MALE";
    }

    @Benchmark
    public String substring() {
        return source.substring(0, 1);
    }

    @Benchmark
    public String indexOf() {
        return String.valueOf(source.indexOf(0));
    }
}

Results:

+----------------------------------------------------------------------+
| Benchmark                           Mode  Cnt   Score   Error  Units |
+----------------------------------------------------------------------+
| StringFirstCharBenchmark.indexOf    avgt    5  23.777 ? 5.788  ns/op |
| StringFirstCharBenchmark.substring  avgt    5  11.305 ? 1.411  ns/op |
+----------------------------------------------------------------------+

Pretty printing JSON from Jackson 2.2's ObjectMapper

The jackson API has changed:

new ObjectMapper()
.writer()
.withDefaultPrettyPrinter()
.writeValueAsString(new HashMap<String, Object>());

Jackson how to transform JsonNode to ArrayNode without casting?

I would assume at the end of the day you want to consume the data in the ArrayNode by iterating it. For that:

Iterator<JsonNode> iterator = datasets.withArray("datasets").elements();
while (iterator.hasNext()) 
        System.out.print(iterator.next().toString() + " "); 

or if you're into streams and lambda functions:

import com.google.common.collect.Streams;
Streams.stream(datasets.withArray("datasets").elements())
    .forEach( item -> System.out.print(item.toString()) )

Best Practices for mapping one object to another

I would opt for AutoMapper, an open source and free mapping library which allows to map one type into another, based on conventions (i.e. map public properties with the same names and same/derived/convertible types, along with many other smart ones). Very easy to use, will let you achieve something like this:

Model model = Mapper.Map<Model>(dto);

Not sure about your specific requirements, but AutoMapper also supports custom value resolvers, which should help you writing a single, generic implementation of your particular mapper.

Jackson serialization: ignore empty values (or null)

For jackson 2.x

@JsonInclude(JsonInclude.Include.NON_NULL)

just before the field.

How to increase size of DOSBox window?

Looking again at your question, I think I see what's wrong with your conf file. You set:

fullresolution=1366x768 windowresolution=1366x768

That's why you're getting the letterboxing (black on either side). You've essentially told Dosbox that your screen is the same size as your window, but your screen is actually bigger, 1600x900 (or higher) per the Googled specs for that computer. So the 'difference' shows up in black. So you either should change fullresolution to your actual screen resolution, or revert to fullresolution=original default, and only specify the window resolution.

So now I wonder if you really want fullscreen, though your question asks about only a window. For you are getting a window, but you sized it short of your screen, hence the two black stripes (letterboxing). If you really want fullscreen, then you need to specify the actual resolution of your screen. 1366x768 is not big enough.

The next issue is, what's the resolution of the program itself? It won't go past its own resolution. So if the program/game is (natively) say 1280x720 (HD), then your window resolution setting shouldn't be bigger than that (remember, it's fixed not dynamic when you use AxB as windowresolution).

Example: DOS Lotus 123 will only extend eight columns and 20 rows. The bigger the Dosbox, the bigger the text, but not more columns and rows. So setting a higher windowresolution for that, only results in bigger text, not more columns and rows. After that you'll have letterboxing.

Hope this helps you better.

jackson deserialization json to java-objects

Your product class needs a parameterless constructor. You can make it private, but Jackson needs the constructor.

As a side note: You should use Pascal casing for your class names. That is Product, and not product.

Automapper missing type map configuration or unsupported mapping - Error

Upgrade Automapper to version 6.2.2. It helped me

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

This is the solution for my old question:

I implemented my own ContextResolver in order to enable the DeserializationConfig.Feature.ACCEPT_SINGLE_VALUE_AS_ARRAY feature.

package org.lig.hadas.services.mapper;

import javax.ws.rs.Produces;
import javax.ws.rs.core.MediaType;
import javax.ws.rs.ext.ContextResolver;
import javax.ws.rs.ext.Provider;

import org.codehaus.jackson.map.DeserializationConfig;
import org.codehaus.jackson.map.ObjectMapper;

@Produces(MediaType.APPLICATION_JSON)
@Provider
public class ObjectMapperProvider implements ContextResolver<ObjectMapper>
{
   ObjectMapper mapper;

   public ObjectMapperProvider(){
       mapper = new ObjectMapper();
       mapper.configure(DeserializationConfig.Feature.ACCEPT_SINGLE_VALUE_AS_ARRAY, true);
   }
   @Override
   public ObjectMapper getContext(Class<?> type) {
       return mapper;
   }
}

And in the web.xml I registered my package into the servlet definition...

<servlet>
    <servlet-name>...</servlet-name>
    <servlet-class>com.sun.jersey.spi.container.servlet.ServletContainer</servlet-class>
    <init-param>
        <param-name>com.sun.jersey.config.property.packages</param-name>
        <param-value>...;org.lig.hadas.services.mapper</param-value>        
    </init-param>
    ...
</servlet>

... all the rest is transparently done by jersey/jackson.

Convert JSON String to Pretty Print JSON output using Jackson

For Jackson 1.9, We can use the following code for pretty print.

ObjectMapper objectMapper = new ObjectMapper();
objectMapper.enable(SerializationConfig.Feature.INDENT_OUTPUT);

Java java.sql.SQLException: Invalid column index on preparing statement

As @TechSpellBound suggested remove the quotes around the ? signs. Then add a space character at the end of each row in your concatenated string. Otherwise the entire query will be sent as (using only part of it as an example) : .... WHERE bookings.booking_end < date ?OR bookings.booking_start > date ?GROUP BY ....

The ? and the OR needs to be seperated by a space character. Do it wherever needed in the query string.

Jackson - best way writes a java list to a json array

In objectMapper we have writeValueAsString() which accepts object as parameter. We can pass object list as parameter get the string back.

List<Apartment> aptList =  new ArrayList<Apartment>();
    Apartment aptmt = null;
    for(int i=0;i<5;i++){
         aptmt= new Apartment();
         aptmt.setAptName("Apartment Name : ArrowHead Ranch");
         aptmt.setAptNum("3153"+i);
         aptmt.setPhase((i+1));
         aptmt.setFloorLevel(i+2);
         aptList.add(aptmt);
    }
mapper.writeValueAsString(aptList)

Only using @JsonIgnore during serialization, but not deserialization

You can use @JsonIgnoreProperties at class level and put variables you want to igonre in json in "value" parameter.Worked for me fine.

@JsonIgnoreProperties(value = { "myVariable1","myVariable2" })
public class MyClass {
      private int myVariable1;,
      private int myVariable2;
}

Convert Java Object to JsonNode in Jackson

As of Jackson 1.6, you can use:

JsonNode node = mapper.valueToTree(map);

or

JsonNode node = mapper.convertValue(object, JsonNode.class);

Source: is there a way to serialize pojo's directly to treemodel?

Jackson - Deserialize using generic class

Just write a static method in Util class. I am reading a Json from a file. you can give String also to readValue

public static <T> T convertJsonToPOJO(String filePath, Class<?> target) throws JsonParseException, JsonMappingException, IOException, ClassNotFoundException {
        ObjectMapper objectMapper = new ObjectMapper();
        return objectMapper.readValue(new File(filePath), objectMapper .getTypeFactory().constructCollectionType(List.class, Class.forName(target.getName())));
}

Usage:

List<TaskBean> list =  Util.<List<TaskBean>>convertJsonToPOJO("E:/J2eeWorkspaces/az_workspace_svn/az-client-service/dir1/dir2/filename.json", TaskBean.class);

How to prevent null values inside a Map and null fields inside a bean from getting serialized through Jackson

If it's reasonable to alter the original Map data structure to be serialized to better represent the actual value wanted to be serialized, that's probably a decent approach, which would possibly reduce the amount of Jackson configuration necessary. For example, just remove the null key entries, if possible, before calling Jackson. That said...


To suppress serializing Map entries with null values:

Before Jackson 2.9

you can still make use of WRITE_NULL_MAP_VALUES, but note that it's moved to SerializationFeature:

mapper.configure(SerializationFeature.WRITE_NULL_MAP_VALUES, false);

Since Jackson 2.9

The WRITE_NULL_MAP_VALUES is deprecated, you can use the below equivalent:

mapper.setDefaultPropertyInclusion(
   JsonInclude.Value.construct(Include.ALWAYS, Include.NON_NULL))

To suppress serializing properties with null values, you can configure the ObjectMapper directly, or make use of the @JsonInclude annotation:

mapper.setSerializationInclusion(Include.NON_NULL);

or:

@JsonInclude(Include.NON_NULL)
class Foo
{
  public String bar;

  Foo(String bar)
  {
    this.bar = bar;
  }
}

To handle null Map keys, some custom serialization is necessary, as best I understand.

A simple approach to serialize null keys as empty strings (including complete examples of the two previously mentioned configurations):

import java.io.IOException;
import java.util.HashMap;
import java.util.Map;

import com.fasterxml.jackson.annotation.JsonInclude.Include;
import com.fasterxml.jackson.core.JsonGenerator;
import com.fasterxml.jackson.core.JsonProcessingException;
import com.fasterxml.jackson.databind.JsonSerializer;
import com.fasterxml.jackson.databind.ObjectMapper;
import com.fasterxml.jackson.databind.SerializationFeature;
import com.fasterxml.jackson.databind.SerializerProvider;

public class JacksonFoo
{
  public static void main(String[] args) throws Exception
  {
    Map<String, Foo> foos = new HashMap<String, Foo>();
    foos.put("foo1", new Foo("foo1"));
    foos.put("foo2", new Foo(null));
    foos.put("foo3", null);
    foos.put(null, new Foo("foo4"));

    // System.out.println(new ObjectMapper().writeValueAsString(foos));
    // Exception: Null key for a Map not allowed in JSON (use a converting NullKeySerializer?)

    ObjectMapper mapper = new ObjectMapper();
    mapper.configure(SerializationFeature.WRITE_NULL_MAP_VALUES, false);
    mapper.setSerializationInclusion(Include.NON_NULL);
    mapper.getSerializerProvider().setNullKeySerializer(new MyNullKeySerializer());
    System.out.println(mapper.writeValueAsString(foos));
    // output: 
    // {"":{"bar":"foo4"},"foo2":{},"foo1":{"bar":"foo1"}}
  }
}

class MyNullKeySerializer extends JsonSerializer<Object>
{
  @Override
  public void serialize(Object nullKey, JsonGenerator jsonGenerator, SerializerProvider unused) 
      throws IOException, JsonProcessingException
  {
    jsonGenerator.writeFieldName("");
  }
}

class Foo
{
  public String bar;

  Foo(String bar)
  {
    this.bar = bar;
  }
}

To suppress serializing Map entries with null keys, further custom serialization processing would be necessary.

NoClassDefFoundError on Maven dependency

when I try to run it, I get NoClassDefFoundError

Run it how? You're probably trying to run it with eclipse without having correctly imported your maven classpath. See the m2eclipse plugin for integrating maven with eclipse for that.

To verify that your maven config is correct, you could run your app with the exec plugin using:

mvn exec:java -D exec.mainClass=<your main class>

Update: First, regarding your error when running exec:java, your main class is tr.edu.hacettepe.cs.b21127113.bil138_4.App. When talking about class names, they're (almost) always dot-separated. The simple class name is just the last part: App in your case. The fully-qualified name is the full package plus the simple class name, and that's what you give to maven or java when you want to run something. What you were trying to use was a file system path to a source file. That's an entirely different beast. A class name generally translates directly to a class file that's found in the class path, as compared to a source file in the file system. In your specific case, the class file in question would probably be at target/classes/tr/edu/hacettepe/cs/b21127113/bil138_4/App.class because maven compiles to target/classes, and java traditionally creates a directory for each level of packaging.

Your original problem is simply that you haven't put the Jackson jars on your class path. When you run a java program from the command line, you have to set the class path to let it know where it can load classes from. You've added your own jar, but not the other required ones. Your comment makes me think you don't understand how to manually build a class path. In short, the class path can have two things: directories containing class files and jars containing class files. Directories containing jars won't work. For more details on building a class path, see "Setting the class path" and the java and javac tool documentation.

Your class path would need to be at least, and without the line feeds:

target/bil138_4-0.0.1-SNAPSHOT.jar:
/home/utdemir/.m2/repository/org/codehaus/jackson/jackson-core-asl/1.9.6/jackson-core-asl-1.9.6.jar:
/home/utdemir/.m2/repository/org/codehaus/jackson/jackson-mapper-asl/1.9.6/jackson-mapper-asl-1.9.6.jar

Note that the separator on Windows is a semicolon (;).

I apologize for not noticing it sooner. The problem was sitting there in your original post, but I missed it.

PHP - Indirect modification of overloaded property

This is occurring due to how PHP treats overloaded properties in that they are not modifiable or passed by reference.

See the manual for more information regarding overloading.

To work around this problem you can either use a __set function or create a createObject method.

Below is a __get and __set that provides a workaround to a similar situation to yours, you can simply modify the __set to suite your needs.

Note the __get never actually returns a variable. and rather once you have set a variable in your object it no longer is overloaded.

/**
 * Get a variable in the event.
 *
 * @param  mixed  $key  Variable name.
 *
 * @return  mixed|null
 */
public function __get($key)
{
    throw new \LogicException(sprintf(
        "Call to undefined event property %s",
        $key
    ));
}

/**
 * Set a variable in the event.
 *
 * @param  string  $key  Name of variable
 *
 * @param  mixed  $value  Value to variable
 *
 * @return  boolean  True
 */
public function __set($key, $value)
{
    if (stripos($key, '_') === 0 && isset($this->$key)) {
        throw new \LogicException(sprintf(
            "%s is a read-only event property", 
            $key
        ));
    }
    $this->$key = $value;
    return true;
}

Which will allow for:

$object = new obj();
$object->a = array();
$object->a[] = "b";
$object->v = new obj();
$object->v->a = "b";

Tomcat 7 "SEVERE: A child container failed during start"

"there is no problem with tomcat".

I have suffered 4-5 days to resolve the issue (same issue mentioned above). here i was using tomcat 8.5. Finally, the issue got resolved, the issue was with the "Corrupted jar files". You have to delete all your .m2 repository (for me C:\Users\Bandham.m2\repository). den run "mvn clean install" command from your project folder.

happy coding.

Give one UP if it is solved your problem.

Deserialize JSON to ArrayList<POJO> using Jackson

This variant looks more simple and elegant.

CollectionType typeReference =
    TypeFactory.defaultInstance().constructCollectionType(List.class, Dto.class);
List<Dto> resultDto = objectMapper.readValue(content, typeReference);

Neither BindingResult nor plain target object for bean name available as request attribute

Just add

model.addAttribute("login", new Login());

to your method ..

it will work..

java.lang.NoSuchMethodError: javax.servlet.ServletContext.getContextPath()Ljava/lang/String;

java.lang.NoSuchMethodError: javax.servlet.ServletContext.getContextPath()Ljava/lang/String;

That method was added in Servlet 2.5.

So this problem can have at least 3 causes:

  1. The servlet container does not support Servlet 2.5.
  2. The web.xml is not declared conform Servlet 2.5 or newer.
  3. The webapp's runtime classpath is littered with servlet container specific JAR files of a different servlet container make/version which does not support Servlet 2.5.

To solve it,

  1. Make sure that your servlet container supports at least Servlet 2.5. That are at least Tomcat 6, Glassfish 2, JBoss AS 4.1, etcetera. Tomcat 5.5 for example supports at highest Servlet 2.4. If you can't upgrade Tomcat, then you'd need to downgrade Spring to a Servlet 2.4 compatible version.
  2. Make sure that the root declaration of web.xml complies Servlet 2.5 (or newer, at least the highest whatever your target runtime supports). For an example, see also somewhere halfway our servlets wiki page.
  3. Make sure that you don't have any servlet container specific libraries like servlet-api.jar or j2ee.jar in /WEB-INF/lib or even worse, the JRE/lib or JRE/lib/ext. They do not belong there. This is a pretty common beginner's mistake in an attempt to circumvent compilation errors in an IDE, see also How do I import the javax.servlet API in my Eclipse project?.

Serializing with Jackson (JSON) - getting "No serializer found"?

If you use Lomdok libraray (https://projectlombok.org/) then add @Data (https://projectlombok.org/features/Data) annotation to your data object class.

How do I perform an insert and return inserted identity with Dapper?

I see answer for sql server, well here it is for MySql using a transaction


    Dim sql As String = "INSERT INTO Empleado (nombres, apepaterno, apematerno, direccion, colonia, cp, municipio, estado, tel, cel, correo, idrol, relojchecadorid, relojchecadorid2, `activo`,`extras`,`rfc`,`nss`,`curp`,`imagen`,sueldoXHra, IMSSCotiza, thumb) VALUES (@nombres, @apepaterno, @apematerno, @direccion, @colonia, @cp, @municipio, @estado, @tel, @cel, @correo, @idrol, @relojchecadorid, @relojchecadorid2, @activo, @extras, @rfc, @nss, @curp, @imagen,@sueldoXHra,@IMSSCotiza, @thumb)"
    
            Using connection As IDbConnection = New MySqlConnection(getConnectionString())
                connection.Open()
                Using transaction = connection.BeginTransaction
                    Dim res = connection.Execute(sql, New With {reg.nombres, reg.apepaterno, reg.apematerno, reg.direccion, reg.colonia, reg.cp, reg.municipio, reg.estado, reg.tel, reg.cel, reg.correo, reg.idrol, reg.relojchecadorid, reg.relojchecadorid2, reg.activo, reg.extras, reg.rfc, reg.nss, reg.curp, reg.imagen, reg.thumb, reg.sueldoXHra, reg.IMSSCotiza}, commandTimeout:=180, transaction:=transaction)
                    lastInsertedId = connection.ExecuteScalar("SELECT LAST_INSERT_ID();", transaction:=transaction)
                    If res > 0 Then 
transaction.Commit()
return true
end if
                    
                End Using
            End Using

how to change listen port from default 7001 to something different?

As my experience, you can add another domain which listens different port than 7001, and use this domain in to deploy app.

Here's an example: http://st-curriculum.oracle.com/obe/fmw/wls/10g/r3/installconfig/install_wls/install_wls.htm

HTH.

Configuring ObjectMapper in Spring

I am using Spring 4.1.6 and Jackson FasterXML 2.1.4.

    <mvc:annotation-driven>
        <mvc:message-converters>
            <bean class="org.springframework.http.converter.json.MappingJackson2HttpMessageConverter">
                <property name="objectMapper">
                    <bean class="com.fasterxml.jackson.databind.ObjectMapper">
                        <!-- ?????null??-->
                        <property name="serializationInclusion" value="NON_NULL"/>
                    </bean>
                </property>
            </bean>
        </mvc:message-converters>
    </mvc:annotation-driven>

this works at my applicationContext.xml configration

Jackson JSON: get node name from json-tree

Clarification Here:

While this will work:

 JsonNode rootNode = objectMapper.readTree(file);
 Iterator<Map.Entry<String, JsonNode>> fields = rootNode.fields();
 while (fields.hasNext()) {
    Map.Entry<String, JsonNode> entry = fields.next();
    log.info(entry.getKey() + ":" + entry.getValue())
 }

This will not:

JsonNode rootNode = objectMapper.readTree(file);

while (rootNode.fields().hasNext()) {
    Map.Entry<String, JsonNode> entry = rootNode.fields().next();
    log.info(entry.getKey() + ":" + entry.getValue())
}

So be careful to declare the Iterator as a variable and use that.

Be sure to use the fasterxml library rather than codehaus.

How to parse a JSON string to an array using Jackson

The other answer is correct, but for completeness, here are other ways:

List<SomeClass> list = mapper.readValue(jsonString, new TypeReference<List<SomeClass>>() { });
SomeClass[] array = mapper.readValue(jsonString, SomeClass[].class);

How do I use a custom Serializer with Jackson?

In my case (Spring 3.2.4 and Jackson 2.3.1), XML configuration for custom serializer:

<mvc:annotation-driven>
    <mvc:message-converters register-defaults="false">
        <bean class="org.springframework.http.converter.json.MappingJackson2HttpMessageConverter">
            <property name="objectMapper">
                <bean class="org.springframework.http.converter.json.Jackson2ObjectMapperFactoryBean">
                    <property name="serializers">
                        <array>
                            <bean class="com.example.business.serializer.json.CustomObjectSerializer"/>
                        </array>
                    </property>
                </bean>
            </property>
        </bean>
    </mvc:message-converters>
</mvc:annotation-driven>

was in unexplained way overwritten back to default by something.

This worked for me:

CustomObject.java

@JsonSerialize(using = CustomObjectSerializer.class)
public class CustomObject {

    private Long value;

    public Long getValue() {
        return value;
    }

    public void setValue(Long value) {
        this.value = value;
    }
}

CustomObjectSerializer.java

public class CustomObjectSerializer extends JsonSerializer<CustomObject> {

    @Override
    public void serialize(CustomObject value, JsonGenerator jgen,
        SerializerProvider provider) throws IOException,JsonProcessingException {
        jgen.writeStartObject();
        jgen.writeNumberField("y", value.getValue());
        jgen.writeEndObject();
    }

    @Override
    public Class<CustomObject> handledType() {
        return CustomObject.class;
    }
}

No XML configuration (<mvc:message-converters>(...)</mvc:message-converters>) is needed in my solution.

How to specify jackson to only use fields - preferably globally

for jackson 1.9.10 I use

ObjectMapper mapper = new ObjectMapper();

mapper.setVisibility(JsonMethod.ALL, Visibility.NONE);
mapper.setVisibility(JsonMethod.FIELD, Visibility.ANY);

to turn of auto dedection.

How to use Jackson to deserialise an array of objects

you could also create a class which extends ArrayList:

public static class MyList extends ArrayList<Myclass> {}

and then use it like:

List<MyClass> list = objectMapper.readValue(json, MyList.class);

How to deserialize JS date using Jackson?

There is a good blog about this topic: http://www.baeldung.com/jackson-serialize-dates Use @JsonFormat looks the most simple way.

public class Event {
    public String name;

    @JsonFormat
      (shape = JsonFormat.Shape.STRING, pattern = "dd-MM-yyyy hh:mm:ss")
    public Date eventDate;
}

Ignore mapping one property with Automapper

Hello All Please Use this it's working fine... for auto mapper use multiple .ForMember in C#

        if (promotionCode.Any())
        {
            Mapper.Reset();
            Mapper.CreateMap<PromotionCode, PromotionCodeEntity>().ForMember(d => d.serverTime, o => o.MapFrom(s => s.promotionCodeId == null ? "date" : String.Format("{0:dd/MM/yyyy h:mm:ss tt}", DateTime.UtcNow.AddHours(7.0))))
                .ForMember(d => d.day, p => p.MapFrom(s => s.code != "" ? LeftTime(Convert.ToInt32(s.quantity), Convert.ToString(s.expiryDate), Convert.ToString(DateTime.UtcNow.AddHours(7.0))) : "Day"))
                .ForMember(d => d.subCategoryname, o => o.MapFrom(s => s.subCategoryId == 0 ? "" : Convert.ToString(subCategory.Where(z => z.subCategoryId.Equals(s.subCategoryId)).FirstOrDefault().subCategoryName)))
                .ForMember(d => d.optionalCategoryName, o => o.MapFrom(s => s.optCategoryId == 0 ? "" : Convert.ToString(optionalCategory.Where(z => z.optCategoryId.Equals(s.optCategoryId)).FirstOrDefault().optCategoryName)))
                .ForMember(d => d.logoImg, o => o.MapFrom(s => s.vendorId == 0 ? "" : Convert.ToString(vendorImg.Where(z => z.vendorId.Equals(s.vendorId)).FirstOrDefault().logoImg)))
                .ForMember(d => d.expiryDate, o => o.MapFrom(s => s.expiryDate == null ? "" : String.Format("{0:dd/MM/yyyy h:mm:ss tt}", s.expiryDate))); 
            var userPromotionModel = Mapper.Map<List<PromotionCode>, List<PromotionCodeEntity>>(promotionCode);
            return userPromotionModel;
        }
        return null;

Spring configure @ResponseBody JSON format

Yes but what happens if you start using mixins for example, you cant be having ObjectMapper as a singleton because you will be applying the configuration globally. So you will be adding or setting the mixin classes on the same ObjectMapper instance?

Jackson with JSON: Unrecognized field, not marked as ignorable

using Jackson 2.6.0, this worked for me:

private static final ObjectMapper objectMapper = 
    new ObjectMapper()
        .configure(DeserializationFeature.FAIL_ON_UNKNOWN_PROPERTIES, false);

and with setting:

@JsonIgnoreProperties(ignoreUnknown = true)

Strange Jackson exception being thrown when serializing Hibernate object

I am New to Jackson API, when i got the "org.codehaus.jackson.map.JsonMappingException: No serializer found for class com.company.project.yourclass" , I added the getter and setter to com.company.project.yourclass, that helped me to use the ObjectMapper's mapper object to write the java object into a flat file.

Find size and free space of the filesystem containing a given file

As of Python 3.3, there an easy and direct way to do this with the standard library:

$ cat free_space.py 
#!/usr/bin/env python3

import shutil

total, used, free = shutil.disk_usage(__file__)
print(total, used, free)

$ ./free_space.py 
1007870246912 460794834944 495854989312

These numbers are in bytes. See the documentation for more info.

Namespace not recognized (even though it is there)

I've had a similar issue, that took a bit to troubleshoot, so I thought to share it:

The namespace that could not be resolved in my case was Company.Project.Common.Models.EF. I had added a file in a new Company.Project.BusinessLogic.Common namespace.

The majority of the files were having a

using Company.Project;

And then referencing the models as Common.Models.EF. All the files that also had a

using Company.Project.BusinessLogic;

Were failing as VS could not determine which namespace to use.

The solution has been to change the second namespace to Company.Project.BusinessLogic.CommonServices

Should I declare Jackson's ObjectMapper as a static field?

Although ObjectMapper is thread safe, I would strongly discourage from declaring it as a static variable, especially in multithreaded application. Not even because it is a bad practice, but because you are running a heavy risk of deadlocking. I am telling it from my own experience. I created an application with 4 identical threads that were getting and processing JSON data from web services. My application was frequently stalling on the following command, according to the thread dump:

Map aPage = mapper.readValue(reader, Map.class);

Beside that, performance was not good. When I replaced static variable with the instance based variable, stalling disappeared and performance quadrupled. I.e. 2.4 millions JSON documents were processed in 40min.56sec., instead of 2.5 hours previously.

Address already in use: JVM_Bind

You can try to use TCPView utility.

Try to find in the localport column is there any process worked on "busy" port. Right click and end the process. Then try to start the Tomcat.

Its really works for me.

javax.faces.application.ViewExpiredException: View could not be restored

I add the following configuration to web.xml and it got resolved.

<context-param>
    <param-name>com.sun.faces.numberOfViewsInSession</param-name>
    <param-value>500</param-value>
</context-param>
<context-param>
    <param-name>com.sun.faces.numberOfLogicalViews</param-name>
    <param-value>500</param-value>
</context-param>

JUnit tests pass in Eclipse but fail in Maven Surefire

Usually when tests pass in eclipse and fail with maven it is a classpath issue because it is the main difference between the two.

So you can check the classpath with maven -X test and check the classpath of eclipse via the menus or in the .classpath file in the root of your project.

Are you sure for example that personservice-test.xml is in the classpath ?

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

You can use Json from the action directly,

Your action would be something like this:

virtual public JsonResult DisplaySomeWidget(int id)
{
    SomeModelView returnData = someDataMapper.getbyid(id);
    return Json(returnData);
}

Edit

Just saw that you assume this is the Model of a View so the above isn't strictly correct, you would have to make an Ajax call to the controller method to get this, the ascx would not then have a model per se, I will leave my code in just in case it is useful to you and you can amend the call

Edit 2 just put id into the code

How to serialize Joda DateTime with Jackson JSON processor?

I'm using Java 8 and this worked for me.

Add the dependency on pom.xml

<dependency>
    <groupId>com.fasterxml.jackson.datatype</groupId>
    <artifactId>jackson-datatype-jsr310</artifactId>
    <version>2.4.0</version>
</dependency>

and add JodaModule on your ObjectMapper

ObjectMapper mapper = new ObjectMapper();
mapper.registerModule(new JodaModule());

./configure : /bin/sh^M : bad interpreter

Your configure file contains CRLF line endings (windows style) instead of simple LF line endings (unix style). Did you transfer it using FTP mode ASCII from Windows?

You can use

dos2unix configure

to fix this, or open it in vi and use :%s/^M//g; to substitute them all (use CTRL+V, CTRL+M to get the ^M)

How can I select all rows with sqlalchemy?

You can easily import your model and run this:

from models import User

# User is the name of table that has a column name
users = User.query.all()

for user in users:
    print user.name

How do I write good/correct package __init__.py files

__all__ is very good - it helps guide import statements without automatically importing modules http://docs.python.org/tutorial/modules.html#importing-from-a-package

using __all__ and import * is redundant, only __all__ is needed

I think one of the most powerful reasons to use import * in an __init__.py to import packages is to be able to refactor a script that has grown into multiple scripts without breaking an existing application. But if you're designing a package from the start. I think it's best to leave __init__.py files empty.

for example:

foo.py - contains classes related to foo such as fooFactory, tallFoo, shortFoo

then the app grows and now it's a whole folder

foo/
    __init__.py
    foofactories.py
    tallFoos.py
    shortfoos.py
    mediumfoos.py
    santaslittlehelperfoo.py
    superawsomefoo.py
    anotherfoo.py

then the init script can say

__all__ = ['foofactories', 'tallFoos', 'shortfoos', 'medumfoos',
           'santaslittlehelperfoo', 'superawsomefoo', 'anotherfoo']
# deprecated to keep older scripts who import this from breaking
from foo.foofactories import fooFactory
from foo.tallfoos import tallFoo
from foo.shortfoos import shortFoo

so that a script written to do the following does not break during the change:

from foo import fooFactory, tallFoo, shortFoo

When should use Readonly and Get only properties

Methods suggest something has to happen to return the value, properties suggest that the value is already there. This is a rule of thumb, sometimes you might want a property that does a little work (i.e. Count), but generally it's a useful way to decide.

Issue pushing new code in Github

When you created your repository on GitHub, you created a README.md, which is a new commit.

Your local repository doesn't know about this commit yet. Hence:

Updates were rejected because the remote contains work that you do not have locally.

You may want to find to follow this advice:

You may want to first merge the remote changes (e.g., 'git pull') before pushing again.

That is:

git pull
# Fix any merge conflicts, if you have a `README.md` locally
git push -u origin master

Space between two rows in a table?

Simply put div inside the td and set the following styles of div:

margin-bottom: 20px;
height: 40px;
float: left;
width: 100%;

Static Initialization Blocks

You first need to understand that your application classes themselves are instantiated to java.class.Class objects during runtime. This is when your static blocks are ran. So you can actually do this:

public class Main {

    private static int myInt;

    static {
        myInt = 1;
        System.out.println("myInt is 1");
    }

    //  needed only to run this class
    public static void main(String[] args) {
    }

}

and it would print "myInt is 1" to console. Note that I haven't instantiated any class.

When to use HashMap over LinkedList or ArrayList and vice-versa

Lists and Maps are different data structures. Maps are used for when you want to associate a key with a value and Lists are an ordered collection.

Map is an interface in the Java Collection Framework and a HashMap is one implementation of the Map interface. HashMap are efficient for locating a value based on a key and inserting and deleting values based on a key. The entries of a HashMap are not ordered.

ArrayList and LinkedList are an implementation of the List interface. LinkedList provides sequential access and is generally more efficient at inserting and deleting elements in the list, however, it is it less efficient at accessing elements in a list. ArrayList provides random access and is more efficient at accessing elements but is generally slower at inserting and deleting elements.

Unpacking a list / tuple of pairs into two lists / tuples

list1 = (x[0] for x in source_list)
list2 = (x[1] for x in source_list)

Using Ajax.BeginForm with ASP.NET MVC 3 Razor

Example

//In Model

public class MyModel
{  
   [Required]
    public string Name{ get; set; }
}

//In PartailView //PartailView.cshtml

@model MyModel

<div>
    <div>
      @Html.LabelFor(model=>model.Name)
    </div>
    <div>
        @Html.EditorFor(model=>model.Name)
        @Html.ValidationMessageFor(model => model.Name)
    </div>
</div>

In Index.cshtml view

@model MyModel
<div id="targetId">
    @{Html.RenderPartial("PartialView",Model)}
</div>

@using(Ajax.BeginForm("AddName", new AjaxOptions { UpdateTargetId = "targetId", HttpMethod = "Post" }))
{
     <div>
        <input type="submit" value="Add Unit" />
    </div>
}

In Controller

public ActionResult Index()
{
  return View(new MyModel());
}


public string AddName(MyModel model)
{
   string HtmlString = RenderPartialViewToString("PartailView",model);
   return HtmlString;
}


protected string RenderPartialViewToString(string viewName, object model)
        {
            if (string.IsNullOrEmpty(viewName))
                viewName = ControllerContext.RouteData.GetRequiredString("action");

            ViewData.Model = model;

            using (StringWriter sw = new StringWriter())
            {
                ViewEngineResult viewResult = ViewEngines.Engines.FindPartialView(ControllerContext, viewName);
                ViewContext viewContext = new ViewContext(ControllerContext, viewResult.View, ViewData, TempData, sw);
                viewResult.View.Render(viewContext, sw);
                return sw.GetStringBuilder().ToString();
            }
        }

you must be pass ViewName and Model to RenderPartialViewToString method. it will return you view with validation which are you applied in model and append the content in "targetId" div in Index.cshtml. I this way by catching RenderHtml of partial view you can apply validation.

Uncaught SyntaxError: Unexpected token with JSON.parse

You should validate your JSON string here.

A valid JSON string must have double quotes around the keys:

JSON.parse({"u1":1000,"u2":1100})       // will be ok

If there are no quotes, it will cause an error:

JSON.parse({u1:1000,u2:1100})    
// error Uncaught SyntaxError: Unexpected token u in JSON at position 2

Using single quotes will also cause an error:

JSON.parse({'u1':1000,'u2':1100})    
// error Uncaught SyntaxError: Unexpected token ' in JSON at position 1

How to replace captured groups only?

With two capturing groups would have been also possible; I would have also included two dashes, as additional left and right boundaries, before and after the digits, and the modified expression would have looked like:

(.*name=".+_)\d+(_[^"]+".*)

_x000D_
_x000D_
const regex = /(.*name=".+_)\d+(_[^"]+".*)/g;_x000D_
const str = `some_data_before name="some_text_0_some_text" and then some_data after`;_x000D_
const subst = `$1!NEW_ID!$2`;_x000D_
const result = str.replace(regex, subst);_x000D_
console.log(result);
_x000D_
_x000D_
_x000D_


If you wish to explore/simplify/modify the expression, it's been explained on the top right panel of regex101.com. If you'd like, you can also watch in this link, how it would match against some sample inputs.


RegEx Circuit

jex.im visualizes regular expressions:

enter image description here

Examples of good gotos in C or C++

@Greg:

Why not do your example like this:

void foo()
{
    if (doA())
    {    
        if (doB())
        {
          if (!doC())
          {
             UndoA();
             UndoB();
          }
        }
        else
        {
          UndoA();
        }
    }
    return;
}

Read file from aws s3 bucket using node fs

var fileStream = fs.createWriteStream('/path/to/file.jpg');
var s3Stream = s3.getObject({Bucket: 'myBucket', Key: 'myImageFile.jpg'}).createReadStream();

// Listen for errors returned by the service
s3Stream.on('error', function(err) {
    // NoSuchKey: The specified key does not exist
    console.error(err);
});

s3Stream.pipe(fileStream).on('error', function(err) {
    // capture any errors that occur when writing data to the file
    console.error('File Stream:', err);
}).on('close', function() {
    console.log('Done.');
});

Reference: https://docs.aws.amazon.com/sdk-for-javascript/v2/developer-guide/requests-using-stream-objects.html

VB.net: Date without time

I almost always use the standard formating ShortDateString, because I want the user to be in control of the actual output of the date.

Code

   Dim d As DateTime = Now
   Debug.WriteLine(d.ToLongDateString)
   Debug.WriteLine(d.ToShortDateString)
   Debug.WriteLine(d.ToString("d"))
   Debug.WriteLine(d.ToString("yyyy-MM-dd"))

Results

Wednesday, December 10, 2008
12/10/2008
12/10/2008
2008-12-10

Note that these results will vary depending on the culture settings on your computer.

Node.js – events js 72 throw er unhandled 'error' event

Close nodejs app running in another shell. Restart the terminal and run the program again.


Another server might be also using the same port that you have used for nodejs. Kill the process that is using nodejs port and run the app.

To find the PID of the application that is using port:8000

$ fuser 8000/tcp
8000/tcp:            16708

Here PID is 16708 Now kill the process using the kill [PID] command

$ kill 16708

What are the performance characteristics of sqlite with very large database files?

I have a 7GB SQLite database. To perform a particular query with an inner join takes 2.6s In order to speed this up I tried adding indexes. Depending on which index(es) I added, sometimes the query went down to 0.1s and sometimes it went UP to as much as 7s. I think the problem in my case was that if a column is highly duplicate then adding an index degrades performance :(

How do you move a file?

Transferring a file using TortoiseSVN:

Step:1 Please Select the files which you want to move, Right-click and drag the files to the folder which you to move them to, A window will popup after follow the below instruction

SVN option

Step 2: After you click the above the commit the file as below mention

SVN Commit

Android: How to open a specific folder via Intent and show its content in a file browser?

This should work:

Uri selectedUri = Uri.parse(Environment.getExternalStorageDirectory() + "/myFolder/");
Intent intent = new Intent(Intent.ACTION_VIEW);
intent.setDataAndType(selectedUri, "resource/folder");

if (intent.resolveActivityInfo(getPackageManager(), 0) != null)
{
    startActivity(intent);
}
else
{
    // if you reach this place, it means there is no any file 
    // explorer app installed on your device
}

Please, be sure that you have any file explorer app installed on your device.

EDIT: added a shantanu's recommendation from the comment.

LIBRARIES: You can also have a look at the following libraries https://android-arsenal.com/tag/35 if the current solution doesn't help you.

A formula to copy the values from a formula to another column

Use =concatenate(). Concatenate is generally used to combine the words of several cells into one, but if you only input one cell it will return that value. There are other methods, but I find this is the best because it is the only method that works when a formula, whose value you wish to return, is in a merged cell.

How to show full column content in a Spark Dataframe?

results.show(20, false) will not truncate. Check the source

20 is the default number of rows displayed when show() is called without any arguments.

React Native fixed footer

if you just use react native so you can use the following code

<View style={{flex:1}}>

{/* Your Main Content*/}
<View style={{flex:3}}>

<ScrollView>
   {/* Your List View ,etc */}
</ScrollView>

</View>

{/* Your Footer */}
<View style={{flex:1}}>
   {/*Elements*/}
</View>


 </View>

also, you can use https://docs.nativebase.io/ in your react native project and then do something like the following

<Container>

{/*Your Main Content*/}
<Content>

<ScrollView>
   {/* Your List View ,etc */}
</ScrollView>

</Content>

{/*Your Footer*/}
<Footer>
   {/*Elements*/}
</Footer>

</Container>

React_Native

NativeBase.io

How to merge every two lines into one from the command line?

paste is good for this job:

paste -d " "  - - < filename

Warning: A non-numeric value encountered

I had this issue with my pagination forward and backward link .... simply set (int ) in front of the variable $Page+1 and it worked...

<?php 
$Page = (isset($_GET['Page']) ? $_GET['Page'] : '');
if ((int)$Page+1<=$PostPagination) {
?>
<li> <a href="Index.php?Page=<?php echo $Page+1; ?>"> &raquo;</a></li>
<?php }
?>

Why won't my PHP app send a 404 error?

if (strstr($_SERVER['REQUEST_URI'],'index.php')){
    header('HTTP/1.0 404 Not Found');
    echo "<h1>404 Not Found</h1>";
    echo "The page that you have requested could not be found.";
    exit();
}

If you look at the last two echo lines, that's where you'll see the content. You can customize it however you want.

Right mime type for SVG images with fonts embedded

There's only one registered mediatype for SVG, and that's the one you listed, image/svg+xml. You can of course serve SVG as XML too, though browsers tend to behave differently in some scenarios if you do, for example I've seen cases where SVG used in CSS backgrounds fail to display unless served with the image/svg+xml mediatype.

What is Func, how and when is it used

Aforementioned answers are great, just putting few points I see might be helpful:

  • Func is built-in delegate type

  • Func delegate type must return a value. Use Action delegate if no return type needed.

  • Func delegate type can have zero to 16 input parameters.

  • Func delegate does not allow ref and out parameters.

  • Func delegate type can be used with an anonymous method or lambda expression.

    Func<int, int, int> Sum = (x, y) => x + y;

How to reload page every 5 seconds?

_x000D_
_x000D_
function reload() {_x000D_
  document.location.reload();_x000D_
}_x000D_
_x000D_
setTimeout(reload, 5000);
_x000D_
_x000D_
_x000D_

Why use Select Top 100 Percent?

I have seen other code which I have inherited which uses SELECT TOP 100 PERCENT

The reason for this is simple: Enterprise Manager used to try to be helpful and format your code to include this for you. There was no point ever trying to remove it as it didn't really hurt anything and the next time you went to change it EM would insert it again.

Windows path in Python

you can use always:

'C:/mydir'

this works both in linux and windows. Other posibility is

'C:\\mydir'

if you have problems with some names you can also try raw string literals:

r'C:\mydir'

however best practice is to use the os.path module functions that always select the correct configuration for your OS:

os.path.join(mydir, myfile)

From python 3.4 you can also use the pathlib module. This is equivelent to the above:

pathlib.Path(mydir, myfile)

or

pathlib.Path(mydir) / myfile

How to display alt text for an image in chrome

Various browsers (mis)handle this in various ways. Using title (an old IE 'standard') isn't particularly appropriate, since the title attribute is a mouseover effect. The jQuery solution above (Alexis) seems on the right track, but I don't think the 'error' occurs at a point where it could be caught. I've had success by replacing at the src with itself, and then catching the error:

$('img').each(function()
{
    $(this).error(function()
    {
        $(this).replaceWith(this.alt);
    }).attr('src',$(this).prop('src'));
});

This, as in the Alexis contribution, has the benefit of removing the missing img image.

How to tell which row number is clicked in a table?

You can use object.rowIndex property which has an index starting at 0.

$("table tr").click(function(){
    alert (this.rowIndex);
});

See a working demo

How to install ia32-libs in Ubuntu 14.04 LTS (Trusty Tahr)

For me, I have to run

sudo dpkg --add-architecture i386

before running Mike Tang's answer. Otherwise, I can't install ia32-libs.

Increase max_execution_time in PHP?

Add this to an htaccess file (and see edit notes added below):

<IfModule mod_php5.c>
   php_value post_max_size 200M
   php_value upload_max_filesize 200M
   php_value memory_limit 300M
   php_value max_execution_time 259200
   php_value max_input_time 259200
   php_value session.gc_maxlifetime 1200
</IfModule>

Additional resources and information:


2021 EDIT:

As PHP and Apache evolve and grow, I think it is important for me to take a moment to mention a few things to consider and possible "gotchas" to consider:

  • PHP can be run as a module or as CGI. It is not recommended to run as CGI as it creates a lot of opportunities for attack vectors [Read More]. Running as a module (the safer option) will trigger the settings to be used if the specific module from <IfModule is loaded.
  • The answer indicates to write mod_php5.c in the first line. If you are using PHP 7, you would replace that with mod_php7.c.
  • Sometimes after you make changes to your .htaccess file, restarting Apache or NGINX will not work. The most common reason for this is you are running PHP-FPM, which runs as a separate process. You need to restart that as well.
  • Remember these are settings that are normally defined in your php.ini config file(s). This method is usually only useful in the event your hosting provider does not give you access to change those files. In circumstances where you can edit the PHP configuration, it is recommended that you apply these settings there.
  • Finally, it's important to note that not all php.ini settings can be configured via an .htaccess file. A file list of php.ini directives can be found here, and the only ones you can change are the ones in the changeable column with the modes PHP_INI_ALL or PHP_INI_PERDIR.

How do I get the last word in each line with bash

tldr;

$ awk '{print $NF}' file.txt | paste -sd, | sed 's/,/, /g'

For a file like this

$ cat file.txt
The quick brown fox
jumps over
the lazy dog.

the given command will print

fox, over, dog.

How it works:

  • awk '{print $NF}' : prints the last field of every line
  • paste -sd, : reads stdin serially (-s, one file at a time) and writes fields comma-delimited (-d,)
  • sed 's/,/, /g' : substitutes "," with ", " globally (for all instances)

References:

How to serialize SqlAlchemy result to JSON?

Python 3.7+ and Flask 1.1+ can use the built-in dataclasses package

from dataclasses import dataclass
from datetime import datetime
from flask import Flask, jsonify
from flask_sqlalchemy import SQLAlchemy


app = Flask(__name__)
db = SQLAlchemy(app)


@dataclass
class User(db.Model):
  id: int
  email: str

  id = db.Column(db.Integer, primary_key=True, auto_increment=True)
  email = db.Column(db.String(200), unique=True)


@app.route('/users/')
def users():
  users = User.query.all()
  return jsonify(users)  


if __name__ == "__main__":
  users = User(email="[email protected]"), User(email="[email protected]")
  db.create_all()
  db.session.add_all(users)
  db.session.commit()
  app.run()

The /users/ route will now return a list of users.

[
  {"email": "[email protected]", "id": 1},
  {"email": "[email protected]", "id": 2}
]

Auto-serialize related models

@dataclass
class Account(db.Model):
  id: int
  users: User

  id = db.Column(db.Integer)
  users = db.relationship(User)  # User model would need a db.ForeignKey field

The response from jsonify(account) would be this.

{  
   "id":1,
   "users":[  
      {  
         "email":"[email protected]",
         "id":1
      },
      {  
         "email":"[email protected]",
         "id":2
      }
   ]
}

Overwrite the default JSON Encoder

from flask.json import JSONEncoder


class CustomJSONEncoder(JSONEncoder):
  "Add support for serializing timedeltas"

  def default(o):
    if type(o) == datetime.timedelta:
      return str(o)
    elif type(o) == datetime.datetime:
      return o.isoformat()
    else:
      return super().default(o)

app.json_encoder = CustomJSONEncoder      

The following untracked working tree files would be overwritten by merge, but I don't care

For those who don't know, git ignores uppercase/lowercase name differences in files and folders. This turns out to be a nightmare when you rename them to the exact same name with a different case.

I encountered this issue when I renamed a folder from "Petstore" to "petstore" (uppercase to lowercase). I had edited my .git/config file to stop ignoring case, made changes, squashed my commits, and stashed my changes to move to a different branch. I could not apply my stashed changes to this other branch.

The fix that I found that worked was to temporarily edit my .git/config file to temporarily ignore case again. This caused git stash apply to succeed. Then, I changed ignoreCase back to false. I then added everything except for the new files in the petstore folder which git oddly claimed were deleted, for whatever reason. I committed my changes, then ran git reset --hard HEAD to get rid of those untracked new files. My commit appeared exactly as expected: the files in the folder were renamed.

I hope that this helps you avoid my same nightmare.

How to convert string to IP address and vice versa

here's easy-to-use, thread-safe c++ functions to convert uint32_t native-endian to string, and string to native-endian uint32_t:

#include <arpa/inet.h> // inet_ntop & inet_pton
#include <string.h> // strerror_r
#include <arpa/inet.h> // ntohl & htonl
using namespace std; // im lazy

string ipv4_int_to_string(uint32_t in, bool *const success = nullptr)
{
    string ret(INET_ADDRSTRLEN, '\0');
    in = htonl(in);
    const bool _success = (NULL != inet_ntop(AF_INET, &in, &ret[0], ret.size()));
    if (success)
    {
        *success = _success;
    }
    if (_success)
    {
        ret.pop_back(); // remove null-terminator required by inet_ntop
    }
    else if (!success)
    {
        char buf[200] = {0};
        strerror_r(errno, buf, sizeof(buf));
        throw std::runtime_error(string("error converting ipv4 int to string ") + to_string(errno) + string(": ") + string(buf));
    }
    return ret;
}
// return is native-endian
// when an error occurs: if success ptr is given, it's set to false, otherwise a std::runtime_error is thrown.
uint32_t ipv4_string_to_int(const string &in, bool *const success = nullptr)
{
    uint32_t ret;
    const bool _success = (1 == inet_pton(AF_INET, in.c_str(), &ret));
    ret = ntohl(ret);
    if (success)
    {
        *success = _success;
    }
    else if (!_success)
    {
        char buf[200] = {0};
        strerror_r(errno, buf, sizeof(buf));
        throw std::runtime_error(string("error converting ipv4 string to int ") + to_string(errno) + string(": ") + string(buf));
    }
    return ret;
}

fair warning, as of writing, they're un-tested. but these functions are exactly what i was looking for when i came to this thread.

"SDK Platform Tools component is missing!"

Installing Android SDKs is done via the "Android SDK and AVD Manager"... there's a shortcut on Eclipse's "Window" menu, or you can run the .exe from the root of your existing Android SDK installation.

Yes I think installing the 2.3 SDK will fix your problem... you can install older SDKs at the same time. The important thing is that the structure of the SDK changed in 2.3 with some tools (such as ADB) moving from sdkroot\tools to sdkroot\platform-tools. Quite possibly the very latest ADT plugin isn't massively backwards-compatible re that change.

Safe Area of Xcode 9

The Safe Area Layout Guide helps avoid underlapping System UI elements when positioning content and controls.

The Safe Area is the area in between System UI elements which are Status Bar, Navigation Bar and Tool Bar or Tab Bar. So when you add a Status bar to your app, the Safe Area shrink. When you add a Navigation Bar to your app, the Safe Area shrinks again.

On the iPhone X, the Safe Area provides additional inset from the top and bottom screen edges in portrait even when no bar is shown. In landscape, the Safe Area is inset from the sides of the screens and the home indicator.

This is taken from Apple's video Designing for iPhone X where they also visualize how different elements affect the Safe Area.

HRESULT: 0x80040154 (REGDB_E_CLASSNOTREG))

This could also be an issue of building the code using a 64 bit configuration. You can try to select x86 as the build platform which can solve this issue. To do this right-click the solution and select Configuration Manager From there you can change the Platform of the project using the 32-bit .dll to x86

How to convert SQL Query result to PANDAS Data Structure?

MySQL Connector

For those that works with the mysql connector you can use this code as a start. (Thanks to @Daniel Velkov)

Used refs:


import pandas as pd
import mysql.connector

# Setup MySQL connection
db = mysql.connector.connect(
    host="<IP>",              # your host, usually localhost
    user="<USER>",            # your username
    password="<PASS>",        # your password
    database="<DATABASE>"     # name of the data base
)   

# You must create a Cursor object. It will let you execute all the queries you need
cur = db.cursor()

# Use all the SQL you like
cur.execute("SELECT * FROM <TABLE>")

# Put it all to a data frame
sql_data = pd.DataFrame(cur.fetchall())
sql_data.columns = cur.column_names

# Close the session
db.close()

# Show the data
print(sql_data.head())

Print string and variable contents on the same line in R

{glue} offers much better string interpolation, see my other answer. Also, as Dainis rightfully mentions, sprintf() is not without problems.

There's also sprintf():

sprintf("Current working dir: %s", wd)

To print to the console output, use cat() or message():

cat(sprintf("Current working dir: %s\n", wd))
message(sprintf("Current working dir: %s\n", wd))

How does inline Javascript (in HTML) work?

It looks suspicious because there is no apparent function that is being returned from!

It is an anonymous function that has been attached to the click event of the object.

why are you doing this, Steve?

Why on earth are you doi.....Ah nevermind, as you've mentioned, it really is widely adopted bad practice :)

How do I convert an integer to binary in JavaScript?

function dec2bin(dec){
    return (dec >>> 0).toString(2);
}

dec2bin(1);    // 1
dec2bin(-1);   // 11111111111111111111111111111111
dec2bin(256);  // 100000000
dec2bin(-256); // 11111111111111111111111100000000

You can use Number.toString(2) function, but it has some problems when representing negative numbers. For example, (-1).toString(2) output is "-1".

To fix this issue, you can use the unsigned right shift bitwise operator (>>>) to coerce your number to an unsigned integer.

If you run (-1 >>> 0).toString(2) you will shift your number 0 bits to the right, which doesn't change the number itself but it will be represented as an unsigned integer. The code above will output "11111111111111111111111111111111" correctly.

This question has further explanation.

-3 >>> 0 (right logical shift) coerces its arguments to unsigned integers, which is why you get the 32-bit two's complement representation of -3.

How to append a jQuery variable value inside the .html tag

See this Link

HTML

<div id="products"></div>

JS

var someone = {
"name":"Mahmoude Elghandour",
"price":"174 SR",
"desc":"WE Will BE WITH YOU"
 };
 var name = $("<div/>",{"text":someone.name,"class":"name"
});

var price = $("<div/>",{"text":someone.price,"class":"price"});
var desc = $("<div />", {   
"text": someone.desc,
"class": "desc"
});
$("#products").fadeIn(1500);
$("#products").append(name).append(price).append(desc);

VSCode regex find & replace submatch math?

Given a regular expression of (foobar) you can reference the first group using $1 and so on if you have more groups in the replace input field.

Can't install via pip because of egg_info error

Try these: pip install --upgrade setuptools or easy_install -U setuptools

HTTP Error 500.22 - Internal Server Error (An ASP.NET setting has been detected that does not apply in Integrated managed pipeline mode.)

In your web.config, make sure these keys exist:

<configuration>
    <system.webServer>
        <validation validateIntegratedModeConfiguration="false"/>
    </system.webServer>
</configuration>

How do I disable fail_on_empty_beans in Jackson?

T o fix this issue configure your JsonDataFormat class like below

ObjectMapper mapper = new ObjectMapper();
mapper.disable(SerializationFeature.FAIL_ON_EMPTY_BEANS);

which is almost equivalent to,

mapper.configure(SerializationConfig.Feature.FAIL_ON_EMPTY_BEANS, false);

MySQL FULL JOIN?

Full join in mysql :(left union right) or (right unoin left)

 SELECT Persons.LastName, Persons.FirstName, Orders.OrderNo
    FROM Persons
    left JOIN Orders
    ON Persons.P_Id=Orders.P_Id
    ORDER BY Persons.LastName

    Union

    SELECT Persons.LastName, Persons.FirstName, Orders.OrderNo
    FROM Persons
    Right JOIN Orders
    ON Persons.P_Id=Orders.P_Id
    ORDER BY Persons.LastName

Interop type cannot be embedded

.NET 4.0 allows primary interop assemblies (or rather, the bits of it that you need) to be embedded into your assembly so that you don't need to deploy them alongside your application.

For whatever reason, this assembly can't be embedded - but it sounds like that's not a problem for you. Just open the Properties tab for the assembly in Visual Studio 2010 and set "Embed Interop Types" to "False".

EDIT: See also Michael Gustus's answer, removing the Class suffix from the types you're using.

MySql ERROR 1045 (28000): Access denied for user 'root'@'localhost' (using password: NO)

Comment by @Niagaradad helped me. I was entering the wrong password the whole time.

Notice the error message

ERROR 1045 (28000): Access denied for user 'ayaz'@'localhost' (using password: YES)

It says, Password: Yes. That means I am sending the password to SQL and that is wrong.

Usually root account doesn't have password if you haven't set one. If you have installed mysql via homebrew then root account won't have a password.

Here is the comment.

so, not exactly the same then. NO means you are not sending a password to MySQL. YES means you are sending a password to MySQL but the incorrect one. Did you specifically set a password for the mysql root user when you installed MySQL? By default there is no password so you can use mysql -u root -p and hit enter.

Can scrapy be used to scrape dynamic content from websites that are using AJAX?

I was using a custom downloader middleware, but wasn't very happy with it, as I didn't manage to make the cache work with it.

A better approach was to implement a custom download handler.

There is a working example here. It looks like this:

# encoding: utf-8
from __future__ import unicode_literals

from scrapy import signals
from scrapy.signalmanager import SignalManager
from scrapy.responsetypes import responsetypes
from scrapy.xlib.pydispatch import dispatcher
from selenium import webdriver
from six.moves import queue
from twisted.internet import defer, threads
from twisted.python.failure import Failure


class PhantomJSDownloadHandler(object):

    def __init__(self, settings):
        self.options = settings.get('PHANTOMJS_OPTIONS', {})

        max_run = settings.get('PHANTOMJS_MAXRUN', 10)
        self.sem = defer.DeferredSemaphore(max_run)
        self.queue = queue.LifoQueue(max_run)

        SignalManager(dispatcher.Any).connect(self._close, signal=signals.spider_closed)

    def download_request(self, request, spider):
        """use semaphore to guard a phantomjs pool"""
        return self.sem.run(self._wait_request, request, spider)

    def _wait_request(self, request, spider):
        try:
            driver = self.queue.get_nowait()
        except queue.Empty:
            driver = webdriver.PhantomJS(**self.options)

        driver.get(request.url)
        # ghostdriver won't response when switch window until page is loaded
        dfd = threads.deferToThread(lambda: driver.switch_to.window(driver.current_window_handle))
        dfd.addCallback(self._response, driver, spider)
        return dfd

    def _response(self, _, driver, spider):
        body = driver.execute_script("return document.documentElement.innerHTML")
        if body.startswith("<head></head>"):  # cannot access response header in Selenium
            body = driver.execute_script("return document.documentElement.textContent")
        url = driver.current_url
        respcls = responsetypes.from_args(url=url, body=body[:100].encode('utf8'))
        resp = respcls(url=url, body=body, encoding="utf-8")

        response_failed = getattr(spider, "response_failed", None)
        if response_failed and callable(response_failed) and response_failed(resp, driver):
            driver.close()
            return defer.fail(Failure())
        else:
            self.queue.put(driver)
            return defer.succeed(resp)

    def _close(self):
        while not self.queue.empty():
            driver = self.queue.get_nowait()
            driver.close()

Suppose your scraper is called "scraper". If you put the mentioned code inside a file called handlers.py on the root of the "scraper" folder, then you could add to your settings.py:

DOWNLOAD_HANDLERS = {
    'http': 'scraper.handlers.PhantomJSDownloadHandler',
    'https': 'scraper.handlers.PhantomJSDownloadHandler',
}

And voilà, the JS parsed DOM, with scrapy cache, retries, etc.

How to create a timer using tkinter?

I have a simple answer to this problem. I created a thread to update the time. In the thread i run a while loop which gets the time and update it. Check the below code and do not forget to mark it as right answer.

from tkinter import *
from tkinter import *
import _thread
import time


def update():
    while True:
      t=time.strftime('%I:%M:%S',time.localtime())
      time_label['text'] = t



win = Tk()
win.geometry('200x200')

time_label = Label(win, text='0:0:0', font=('',15))
time_label.pack()


_thread.start_new_thread(update,())

win.mainloop()

How can I insert into a BLOB column from an insert statement in sqldeveloper?

  1. insert into mytable(id, myblob) values (1,EMPTY_BLOB);
  2. SELECT * FROM mytable mt where mt.id=1 for update
  3. Click on the Lock icon to unlock for editing
  4. Click on the ... next to the BLOB to edit
  5. Select the appropriate tab and click open on the top left.
  6. Click OK and commit the changes.

How Do I 'git fetch' and 'git merge' from a Remote Tracking Branch (like 'git pull')

You don't fetch a branch, you fetch an entire remote:

git fetch origin
git merge origin/an-other-branch

PostgreSQL create table if not exists

There is no CREATE TABLE IF NOT EXISTS... but you can write a simple procedure for that, something like:

CREATE OR REPLACE FUNCTION prc_create_sch_foo_table() RETURNS VOID AS $$
BEGIN

EXECUTE 'CREATE TABLE /* IF NOT EXISTS add for PostgreSQL 9.1+ */ sch.foo (
                    id serial NOT NULL, 
                    demo_column varchar NOT NULL, 
                    demo_column2 varchar NOT NULL,
                    CONSTRAINT pk_sch_foo PRIMARY KEY (id));
                   CREATE INDEX /* IF NOT EXISTS add for PostgreSQL 9.5+ */ idx_sch_foo_demo_column ON sch.foo(demo_column);
                   CREATE INDEX /* IF NOT EXISTS add for PostgreSQL 9.5+ */ idx_sch_foo_demo_column2 ON sch.foo(demo_column2);'
               WHERE NOT EXISTS(SELECT * FROM information_schema.tables 
                        WHERE table_schema = 'sch' 
                            AND table_name = 'foo');

         EXCEPTION WHEN null_value_not_allowed THEN
           WHEN duplicate_table THEN
           WHEN others THEN RAISE EXCEPTION '% %', SQLSTATE, SQLERRM;

END; $$ LANGUAGE plpgsql;

Check if a value exists in pandas dataframe index

Multi index works a little different from single index. Here are some methods for multi-indexed dataframe.

df = pd.DataFrame({'col1': ['a', 'b','c', 'd'], 'col2': ['X','X','Y', 'Y'], 'col3': [1, 2, 3, 4]}, columns=['col1', 'col2', 'col3'])
df = df.set_index(['col1', 'col2'])

in df.index works for the first level only when checking single index value.

'a' in df.index     # True
'X' in df.index     # False

Check df.index.levels for other levels.

'a' in df.index.levels[0] # True
'X' in df.index.levels[1] # True

Check in df.index for an index combination tuple.

('a', 'X') in df.index  # True
('a', 'Y') in df.index  # False

How Can I Bypass the X-Frame-Options: SAMEORIGIN HTTP Header?

Yes Fiddler is an option for me:

  1. Open Fiddler menu > Rules > Customize Rules (this effectively edits CustomRules.js).
  2. Find the function OnBeforeResponse
  3. Add the following lines:

    oSession.oResponse.headers.Remove("X-Frame-Options");
    oSession.oResponse.headers.Add("Access-Control-Allow-Origin", "*");
    
  4. Remember to save the script!

Convert PEM traditional private key to PKCS8 private key

To convert the private key from PKCS#1 to PKCS#8 with openssl:

# openssl pkcs8 -topk8 -inform PEM -outform PEM -nocrypt -in pkcs1.key -out pkcs8.key

That will work as long as you have the PKCS#1 key in PEM (text format) as described in the question.

Passing a variable from one php include file to another: global vs. not

This is all you have to do:

In front.inc

global $name;
$name = 'james';

Check if a Windows service exists and delete in PowerShell

Adapted this to take an input list of servers, specify a hostname and give some helpful output

            $name = "<ServiceName>"
            $servers = Get-content servers.txt

            function Confirm-WindowsServiceExists($name)
            {   
                if (Get-Service -Name $name -Computername $server -ErrorAction Continue)
                {
                    Write-Host "$name Exists on $server"
                    return $true
                }
                    Write-Host "$name does not exist on $server"
                    return $false
            }

            function Remove-WindowsServiceIfItExists($name)
            {   
                $exists = Confirm-WindowsServiceExists $name
                if ($exists)
                {    
                    Write-host "Removing Service $name from $server"
                    sc.exe \\$server delete $name
                }       
            }

            ForEach ($server in $servers) {Remove-WindowsServiceIfItExists($name)}

upgade python version using pip

pip is designed to upgrade python packages and not to upgrade python itself. pip shouldn't try to upgrade python when you ask it to do so.

Don't type pip install python but use an installer instead.

What is the default stack size, can it grow, how does it work with garbage collection?

As you say, local variables and references are stored on the stack. When a method returns, the stack pointer is simply moved back to where it was before the method started, that is, all local data is "removed from the stack". Therefore, there is no garbage collection needed on the stack, that only happens in the heap.

To answer your specific questions:

  • See this question on how to increase the stack size.
  • You can limit the stack growth by:
    • grouping many local variables in an object: that object will be stored in the heap and only the reference is stored on the stack
    • limit the number of nested function calls (typically by not using recursion)
  • For windows, the default stack size is 320k for 32bit and 1024k for 64bit, see this link.

Github permission denied: ssh add agent has no identities

For my mac Big Sur, with gist from answers above, following steps work for me.

$ ssh-keygen -q -t rsa -N 'password' -f ~/.ssh/id_rsa
$ ssh-add ~/.ssh/id_rsa

And added ssh public key to git hub by following instruction;

https://docs.github.com/en/github/authenticating-to-github/adding-a-new-ssh-key-to-your-github-account

If all gone well, you should be able to get the following result;

$ ssh -T [email protected]
Hi user_name! You've successfully authenticated,...

__proto__ VS. prototype in JavaScript

Another good way to understand it:

var foo = {}

/* 
foo.constructor is Object, so foo.constructor.prototype is actually 
Object.prototype; Object.prototype in return is what foo.__proto__ links to. 
*/
console.log(foo.constructor.prototype === foo.__proto__);
// this proves what the above comment proclaims: Both statements evaluate to true.
console.log(foo.__proto__ === Object.prototype);
console.log(foo.constructor.prototype === Object.prototype);

Only after IE11 __proto__ is supported. Before that version, such as IE9, you could use the constructor to get the __proto__.

How to pass a view's onClick event to its parent on Android?

Put

android:duplicateParentState="true"

in child then the views get its drawable state (focused, pressed, etc.) from its direct parent rather than from itself. you can set onclick for parent and it call on child clicked

Java: How to convert a File object to a String object in java?

Readin file with file inputstream and append file content to string.

import java.io.File;
import java.io.FileInputStream;
import java.io.IOException;

public class CopyOffileInputStream {

    public static void main(String[] args) {

        //File file = new File("./store/robots.txt");
        File file = new File("swingloggingsscce.log");

        FileInputStream fis = null;
        String str = "";

        try {
            fis = new FileInputStream(file);
            int content;
            while ((content = fis.read()) != -1) {
                // convert to char and display it
                str += (char) content;
            }

            System.out.println("After reading file");
            System.out.println(str);

        } catch (IOException e) {
            e.printStackTrace();
        } finally {
            try {
                if (fis != null)
                    fis.close();
            } catch (IOException ex) {
                ex.printStackTrace();
            }
        }
    }
}

Selenium Error - The HTTP request to the remote WebDriver timed out after 60 seconds

In my case none of the answers above solved my problem completely. I ended up using the (no-sandbox) mode, the connection with extended timeout period (driver = new RemoteWebDriver(new Uri("http://localhost:4444/wd/hub"), capability, TimeSpan.FromMinutes(3));) and the page load timeout (driver.Manage().Timeouts().PageLoad.Add(System.TimeSpan.FromSeconds(30));) so now my code looks like this:

    public IWebDriver GetRemoteChromeDriver(string downloadPath)
    {
        ChromeOptions chromeOptions = new ChromeOptions();
        chromeOptions.AddArguments(
            "start-maximized",
            "enable-automation",
            "--headless",
            "--no-sandbox", //this is the relevant other arguments came from solving other issues
            "--disable-infobars",
            "--disable-dev-shm-usage",
            "--disable-browser-side-navigation",
            "--disable-gpu",
            "--ignore-certificate-errors");
        capability = chromeOptions.ToCapabilities();

        SetRemoteWebDriver();
        SetImplicitlyWait();
        Thread.Sleep(TimeSpan.FromSeconds(2));
        return driver;
    }
    
    private void SetImplicitlyWait()
    {
        driver.Manage().Timeouts().PageLoad.Add(TimeSpan.FromSeconds(30));
    }


    private void SetRemoteWebDriver()
    {
        driver = new RemoteWebDriver(new Uri("http://localhost:4444/wd/hub"), capability, TimeSpan.FromMinutes(3));
    }

But as I mentioned none of the above method solved my problem, I was continuously get the error, and multiple chromedriver.exe and chrome.exe processses were active (~10 of the chromedriver and ~50 of chrome).

So somewhere I read that after disposing the driver I should wait a few seconds before starting the next test, so I added the following line to dispose method:

    driver?.Quit();
    driver?.Dispose();
    Thread.Sleep(3000);

With this sleep modification I have no longer get the timeout error and there is no unnecessarily opened chromedriver.exe and chrome.exe processses.

I hope I helped someone who struggles with this issue for that long as I did.

SQL: Return "true" if list of records exists?

Given your updated question, these are the simplest forms:

If ProductID is unique you want

SELECT COUNT(*) FROM Products WHERE ProductID IN (1, 10, 100)

and then check that result against 3, the number of products you're querying (this last part can be done in SQL, but it may be easier to do it in C# unless you're doing even more in SQL).

If ProductID is not unique it is

SELECT COUNT(DISTINCT ProductID) FROM Products WHERE ProductID IN (1, 10, 100)

When the question was thought to require returning rows when all ProductIds are present and none otherwise:

SELECT ProductId FROM Products WHERE ProductID IN (1, 10, 100) AND ((SELECT COUNT(*) FROM Products WHERE ProductID IN (1, 10, 100))=3)

or

SELECT ProductId FROM Products WHERE ProductID IN (1, 10, 100) AND ((SELECT COUNT(DISTINCT ProductID) FROM Products WHERE ProductID IN (1, 10, 100))=3)

if you actually intend to do something with the results. Otherwise the simple SELECT 1 WHERE (SELECT ...)=3 will do as other answers have stated or implied.

Print a list in reverse order with range()?

Readibility aside, reversed(range(n)) seems to be faster than range(n)[::-1].

$ python -m timeit "reversed(range(1000000000))"
1000000 loops, best of 3: 0.598 usec per loop
$ python -m timeit "range(1000000000)[::-1]"
1000000 loops, best of 3: 0.945 usec per loop

Just if anyone was wondering :)

Can (domain name) subdomains have an underscore "_" in it?

A note on terminology, in furtherance to Bortzmeyer's answer

One should be clear about definitions. As used here:

  • domain name is the identifier of a resource in a DNS database
  • label is the part of a domain name in between dots
  • hostname is a special type of domain name which identifies Internet hosts

The hostname is subject to the restrictions of RFC 952 and the slight relaxation of RFC 1123

RFC 2181 makes clear that there is a difference between a domain name and a hostname:

...[the fact that] any binary label can have an MX record does not imply that any binary name can be used as the host part of an e-mail address...

So underscores in hostnames are a no-no, underscores in domain names are a-ok.

In practice, one may well see hostnames with underscores. As the Robustness Principle says: "Be conservative in what you send, liberal in what you accept".

A note on encoding

In the 21st century, it turns out that hostnames as well as domain names may be internationalized! This means resorting to encodings in case of labels that contain characters that are outside the allowed set.

In particular, it allows one to encode the _ in hostnames (Update 2017-07: This is doubtful, see comments. The _ still cannot be used in hostnames. Indeed, it cannot even be used in internationalized labels.)

The first RFC for internationalization was RFC 3490 of March 2003, "Internationalizing Domain Names in Applications (IDNA)". Today, we have:

  • RFC 5890 "IDNA: Definitions and Document Framework"
  • RFC 5891 "IDNA: Protocol"
  • RFC 5892 "The Unicode Code Points and IDNA"
  • RFC 5893 "Right-to-Left Scripts for IDNA"
  • RFC 5894 "IDNA: Background, Explanation, and Rationale"
  • RFC 5895 "Mapping Characters for IDNA 2008"

You may also want to check the Wikipedia Entry

RFC 5890 introduces the term LDH (Letter-Digit-Hypen) label for labels used in hostnames and says:

This is the classical label form used, albeit with some additional restrictions, in hostnames (RFC 952). Its syntax is identical to that described as the "preferred name syntax" in Section 3.5 of RFC 1034 as modified by RFC 1123. Briefly, it is a string consisting of ASCII letters, digits, and the hyphen with the further restriction that the hyphen cannot appear at the beginning or end of the string. Like all DNS labels, its total length must not exceed 63 octets.

Going back to simpler times, this Internet draft is an early proposal for hostname internationalization. Hostnames with international characters may be encoded using, for example, 'RACE' encoding.

The author of the 'RACE encoding' proposal notes:

According to RFC 1035, host parts must be case-insensitive, start and end with a letter or digit, and contain only letters, digits, and the hyphen character ("-"). This, of course, excludes any internationalized characters, as well as many other characters in the ASCII character repertoire. Further, domain name parts must be 63 octets or shorter in length.... All post-converted name parts that contain internationalized characters begin with the string "bq--". (...) The string "bq--" was chosen because it is extremely unlikely to exist in host parts before this specification was produced.

How can I find out what version of git I'm running?

Or even just

git version

Results in something like

git version 1.8.3.msysgit.0

Good Patterns For VBA Error Handling

Also relevant to the discussion is the relatively unknown Erl function. If you have numeric labels within your code procedure, e.g.,

Sub AAA()
On Error Goto ErrorHandler

1000:
' code
1100:
' more code
1200:
' even more code that causes an error
1300:
' yet more code
9999: ' end of main part of procedure
ErrorHandler:
If Err.Number <> 0 Then
   Debug.Print "Error: " + CStr(Err.Number), Err.Descrption, _
      "Last Successful Line: " + CStr(Erl)
End If   
End Sub 

The Erl function returns the most recently encountered numberic line label. In the example above, if a run-time error occurs after label 1200: but before 1300:, the Erl function will return 1200, since that is most recenlty sucessfully encountered line label. I find it to be a good practice to put a line label immediately above your error handling block. I typcially use 9999 to indicate that the main part of the procuedure ran to its expected conculsion.

NOTES:

  • Line labels MUST be positive integers -- a label like MadeItHere: isn't recogonized by Erl.

  • Line labels are completely unrelated to the actual line numbers of a VBIDE CodeModule. You can use any positive numbers you want, in any order you want. In the example above, there are only 25 or so lines of code, but the line label numbers begin at 1000. There is no relationship between editor line numbers and line label numbers used with Erl.

  • Line label numbers need not be in any particular order, although if they are not in ascending, top-down order, the efficacy and benefit of Erl is greatly diminished, but Erl will still report the correct number.

  • Line labels are specific to the procedure in which they appear. If procedure ProcA calls procedure ProcB and an error occurs in ProcB that passes control back to ProcA, Erl (in ProcA) will return the most recently encounterd line label number in ProcA before it calls ProcB. From within ProcA, you cannot get the line label numbers that might appear in ProcB.

Use care when putting line number labels within a loop. For example,

For X = 1 To 100
500:
' some code that causes an error
600:
Next X

If the code following line label 500 but before 600 causes an error, and that error arises on the 20th iteration of the loop, Erl will return 500, even though 600 has been encounterd successfully in the previous 19 interations of the loop.

Proper placement of line labels within the procedure is critical to using the Erl function to get truly meaningful information.

There are any number of free utilies on the net that will insert numeric line label in a procedure automatically, so you have fine-grained error information while developing and debugging, and then remove those labels once code goes live.

If your code displays error information to the end user if an unexpected error occurs, providing the value from Erl in that information can make finding and fixing the problem VASTLY simpler than if value of Erl is not reported.

LINQ: Distinct values

In addition to Jon Skeet's answer, you can also use the group by expressions to get the unique groups along w/ a count for each groups iterations:

var query = from e in doc.Elements("whatever")
            group e by new { id = e.Key, val = e.Value } into g
            select new { id = g.Key.id, val = g.Key.val, count = g.Count() };

Youtube iframe wmode issue

recently I saw that sometimes the flash player doesn't recognize &wmode=opaque, istead you should pass &WMode=opaque too (notice the uppercase).

Run Command Prompt Commands

This may be a bit of a read so im sorry in advance. And this is my tried and tested way of doing this, there may be a simpler way but this is from me throwing code at a wall and seeing what stuck

If it can be done with a batch file then the maybe over complicated work around is have c# write a .bat file and run it. If you want user input you could place the input into a variable and have c# write it into the file. it will take trial and error with this way because its like controlling a puppet with another puppet.

here is an example, In this case the function is for a push button in windows forum app that clears the print queue.

using System.IO;
using System;

   public static void ClearPrintQueue()
    {

        //this is the path the document or in our case batch file will be placed
        string docPath =
         Environment.GetFolderPath(Environment.SpecialFolder.MyDocuments);
        //this is the path process.start usues
        string path1 = docPath + "\\Test.bat";

        // these are the batch commands
        // remember its "", the comma separates the lines
        string[] lines =
        {
            "@echo off",
            "net stop spooler",
            "del %systemroot%\\System32\\spool\\Printers\\* /Q",
            "net start spooler",
            //this deletes the file
            "del \"%~f0\"" //do not put a comma on the last line
        };

        //this writes the string to the file
        using (StreamWriter outputFile = new StreamWriter(Path.Combine(docPath, "test.bat")))
        {
            //This writes the file line by line
            foreach (string line in lines)
                outputFile.WriteLine(line);
        }
        System.Diagnostics.Process.Start(path1);

    }

IF you want user input then you could try something like this.

This is for setting the computer IP as static but asking the user what the IP, gateway, and dns server is.

you will need this for it to work

public static void SetIPStatic()
    {
//These open pop up boxes which ask for user input
        string STATIC = Microsoft.VisualBasic.Interaction.InputBox("Whats the static IP?", "", "", 100, 100);
        string SUBNET = Microsoft.VisualBasic.Interaction.InputBox("Whats the Subnet?(Press enter for default)", "255.255.255.0", "", 100, 100);
        string DEFAULTGATEWAY = Microsoft.VisualBasic.Interaction.InputBox("Whats the Default gateway?", "", "", 100, 100);
        string DNS = Microsoft.VisualBasic.Interaction.InputBox("Whats the DNS server IP?(Input required, 8.8.4.4 has already been set as secondary)", "", "", 100, 100);



        //this is the path the document or in our case batch file will be placed
        string docPath =
         Environment.GetFolderPath(Environment.SpecialFolder.MyDocuments);
        //this is the path process.start usues
        string path1 = docPath + "\\Test.bat";

        // these are the batch commands
        // remember its "", the comma separates the lines
        string[] lines =
        {
            "SETLOCAL EnableDelayedExpansion",
            "SET adapterName=",
            "FOR /F \"tokens=* delims=:\" %%a IN ('IPCONFIG ^| FIND /I \"ETHERNET ADAPTER\"') DO (",
            "SET adapterName=%%a",
            "REM Removes \"Ethernet adapter\" from the front of the adapter name",
            "SET adapterName=!adapterName:~17!",
            "REM Removes the colon from the end of the adapter name",
            "SET adapterName=!adapterName:~0,-1!",
//the variables that were set before are used here
            "netsh interface ipv4 set address name=\"!adapterName!\" static " + STATIC + " " + STATIC + " " + DEFAULTGATEWAY,
            "netsh interface ipv4 set dns name=\"!adapterName!\" static " + DNS + " primary",
            "netsh interface ipv4 add dns name=\"!adapterName!\" 8.8.4.4 index=2",
            ")",
            "ipconfig /flushdns",
            "ipconfig /registerdns",
            ":EOF",
            "DEL \"%~f0\"",
            ""
        };

        //this writes the string to the file
        using (StreamWriter outputFile = new StreamWriter(Path.Combine(docPath, "test.bat")))
        {
            //This writes the file line by line
            foreach (string line in lines)
                outputFile.WriteLine(line);
        }
        System.Diagnostics.Process.Start(path1);

    }

Like I said. It may be a little overcomplicated but it never fails unless I write the batch commands wrong.

Downloading jQuery UI CSS from Google's CDN

The Google AJAX Libraries API, which includes jQuery UI (currently v1.10.3), also includes popular themes as per the jQuery UI blog:

Google Ajax Libraries API (CDN)

printf() formatting for hex

The "0x" counts towards the eight character count. You need "%#010x".

Note that # does not append the 0x to 0 - the result will be 0000000000 - so you probably actually should just use "0x%08x" anyway.

How to set DialogFragment's width and height?

I don't see a compelling reason to override onResume or onStart to set the width and height of the Window within DialogFragment's Dialog -- these particular lifecycle methods can get called repeatedly and unnecessarily execute that resizing code more than once due to things like multi window switching, backgrounding then foregrounding the app, and so on. The consequences of that repetition are fairly trivial, but why settle for that?

Setting the width/height instead within an overridden onActivityCreated() method will be an improvement because this method realistically only gets called once per instance of your DialogFragment. For example:

@Override
public void onActivityCreated(Bundle savedInstanceState) {
    super.onActivityCreated(savedInstanceState);

    Window window = getDialog().getWindow();
    assert window != null;

    WindowManager.LayoutParams layoutParams = window.getAttributes();
    layoutParams.width = ViewGroup.LayoutParams.MATCH_PARENT;
    window.setAttributes(layoutParams);
}

Above I just set the width to be match_parent irrespective of device orientation. If you want your landscape dialog to not be so wide, you can do a check of whether getResources().getConfiguration().orientation == Configuration.ORIENTATION_PORTRAIT beforehand.

Can't create handler inside thread which has not called Looper.prepare()

Activity.runOnUiThread() does not work for me. I worked around this issue by creating a regular thread this way:

public class PullTasksThread extends Thread {
   public void run () {
      Log.d(Prefs.TAG, "Thread run...");
   }
}

and calling it from the GL update this way:

new PullTasksThread().start();

How to convert Base64 String to javascript file object like as from file input form?

Way 1: only works for dataURL, not for other types of url.

_x000D_
_x000D_
 function dataURLtoFile(dataurl, filename) {_x000D_
 _x000D_
        var arr = dataurl.split(','),_x000D_
            mime = arr[0].match(/:(.*?);/)[1],_x000D_
            bstr = atob(arr[1]), _x000D_
            n = bstr.length, _x000D_
            u8arr = new Uint8Array(n);_x000D_
            _x000D_
        while(n--){_x000D_
            u8arr[n] = bstr.charCodeAt(n);_x000D_
        }_x000D_
        _x000D_
        return new File([u8arr], filename, {type:mime});_x000D_
    }_x000D_
    _x000D_
    //Usage example:_x000D_
    var file = dataURLtoFile('data:text/plain;base64,aGVsbG8gd29ybGQ=','hello.txt');_x000D_
    console.log(file);
_x000D_
_x000D_
_x000D_

Way 2: works for any type of url, (http url, dataURL, blobURL, etc...)

_x000D_
_x000D_
 //return a promise that resolves with a File instance_x000D_
    function urltoFile(url, filename, mimeType){_x000D_
        return (fetch(url)_x000D_
            .then(function(res){return res.arrayBuffer();})_x000D_
            .then(function(buf){return new File([buf], filename,{type:mimeType});})_x000D_
        );_x000D_
    }_x000D_
    _x000D_
    //Usage example:_x000D_
    urltoFile('data:text/plain;base64,aGVsbG8gd29ybGQ=', 'hello.txt','text/plain')_x000D_
    .then(function(file){ console.log(file);});
_x000D_
_x000D_
_x000D_

Build error: You must add a reference to System.Runtime

It's an old issue but I faced it today in order to fix a build pipeline on our continuous integration server. Adding

<Reference Include="System.Runtime" />

to my .csproj file solved the problem for me.

A bit of context: the interested project is a full .NET Framework 4.6.1 project, without build problem on the development machines. The problem appears only on the build server, which we can't control, may be due to a different SDK version or something similar.

Adding the proposed <Reference solved the build error, at the price of a missing reference warning (yellow triangle on the added entry in the references tree) in Visual Studio.

How to reference a local XML Schema file correctly?

Add one more slash after file:// in the value of xsi:schemaLocation. (You have two; you need three. Think protocol://host/path where protocol is 'file' and host is empty here, yielding three slashes in a row.) You can also eliminate the double slashes along the path. I believe that the double slashes help with file systems that allow spaces in file and directory names, but you wisely avoided that complication in your path naming.

xsi:schemaLocation="http://www.w3schools.com file:///C:/environment/workspace/maven-ws/ProjextXmlSchema/email.xsd"

Still not working? I suggest that you carefully copy the full file specification for the XSD into the address bar of Chrome or Firefox:

file:///C:/environment/workspace/maven-ws/ProjextXmlSchema/email.xsd

If the XSD does not display in the browser, delete all but the last component of the path (email.xsd) and see if you can't display the parent directory. Continue in this manner, walking up the directory structure until you discover where the path diverges from the reality of your local filesystem.

If the XSD does displayed in the browser, state what XML processor you're using, and be prepared to hear that it's broken or that you must work around some limitation. I can tell you that the above fix will work with my Xerces-J-based validator.

How to stop tracking and ignore changes to a file in Git?

The accepted answer still did not work for me

I used

git rm -r --cached .

git add .

git commit -m "fixing .gitignore"

Found the answer from here

What is the default font of Sublime Text?

Yes. You can use Console of Sublime with (Linux):

Ctrl + `

And type:

view.settings().get('font_face')

Get any setting the same way.

How can I make setInterval also work when a tab is inactive in Chrome?

There is a solution to use Web Workers (as mentioned before), because they run in separate process and are not slowed down

I've written a tiny script that can be used without changes to your code - it simply overrides functions setTimeout, clearTimeout, setInterval, clearInterval.

Just include it before all your code.

more info here

How to detect lowercase letters in Python?

There are 2 different ways you can look for lowercase characters:

  1. Use str.islower() to find lowercase characters. Combined with a list comprehension, you can gather all lowercase letters:

    lowercase = [c for c in s if c.islower()]
    
  2. You could use a regular expression:

    import re
    
    lc = re.compile('[a-z]+')
    lowercase = lc.findall(s)
    

The first method returns a list of individual characters, the second returns a list of character groups:

>>> import re
>>> lc = re.compile('[a-z]+')
>>> lc.findall('AbcDeif')
['bc', 'eif']

C++ convert hex string to signed integer

Here's a simple and working method I found elsewhere:

string hexString = "7FF";
int hexNumber;
sscanf(hexString.c_str(), "%x", &hexNumber);

Please note that you might prefer using unsigned long integer/long integer, to receive the value. Another note, the c_str() function just converts the std::string to const char* .

So if you have a const char* ready, just go ahead with using that variable name directly, as shown below [I am also showing the usage of the unsigned long variable for a larger hex number. Do not confuse it with the case of having const char* instead of string]:

const char *hexString = "7FFEA5"; //Just to show the conversion of a bigger hex number
unsigned long hexNumber; //In case your hex number is going to be sufficiently big.
sscanf(hexString, "%x", &hexNumber);

This works just perfectly fine (provided you use appropriate data types per your need).

How to use addTarget method in swift 3

Try this with Swift 3

button.addTarget(self, action:#selector(ClassName.handleRegister(sender:)), for: .touchUpInside)

Good luck!

Loop through each row of a range in Excel

Something like this:

Dim rng As Range
Dim row As Range
Dim cell As Range

Set rng = Range("A1:C2")

For Each row In rng.Rows
  For Each cell in row.Cells
    'Do Something
  Next cell
Next row

A regex for version number parsing

(?ms)^((?:\d+(?!\.\*)\.)+)(\d+)?(\.\*)?$|^(\d+)\.\*$|^(\*|\d+)$

Does exactly match your 6 first examples, and rejects the 4 others

  • group 1: major or major.minor or '*'
  • group 2 if exists: minor or *
  • group 3 if exists: *

You can remove '(?ms)'
I used it to indicate to this regexp to be applied on multi-lines through QuickRex

OpenCV TypeError: Expected cv::UMat for argument 'src' - What is this?

Just add this at start: image = cv2.imread(image)

How to set height property for SPAN

this is to make display:inline-block work in all browsers:

Quirkly enough, in IE (6/7) , if you trigger hasLayout with "zoom:1" and then set the display to inline, it behaves as an inline block.

.inline-block {
    display: inline-block;
    zoom: 1;
    *display: inline;
}

Copy data from another Workbook through VBA

Are you looking for the syntax to open them:

Dim wkbk As Workbook

Set wkbk = Workbooks.Open("C:\MyDirectory\mysheet.xlsx")

Then, you can use wkbk.Sheets(1).Range("3:3") (or whatever you need)

How to plot a subset of a data frame in R?

with(dfr[dfr$var3 < 155,], plot(var1, var2)) should do the trick.

Edit regarding multiple conditions:

with(dfr[(dfr$var3 < 155) & (dfr$var4 > 27),], plot(var1, var2))

How can you sort an array without mutating the original array?

Just copy the array. There are many ways to do that:

function sort(arr) {
  return arr.concat().sort();
}

// Or:
return Array.prototype.slice.call(arr).sort(); // For array-like objects

How to get certain commit from GitHub project

Sivan's answer in gif enter image description here

1.Click on commits in github

2.Select Browse code on the right side of each commit

3.Click on download zip , which will download source code at that point of time of commit

Passing the argument to CMAKE via command prompt

In the CMakeLists.txt file, create a cache variable, as documented here:

SET(FAB "po" CACHE STRING "Some user-specified option")

Source: http://cmake.org/cmake/help/v2.8.8/cmake.html#command:set

Then, either use the GUI (ccmake or cmake-gui) to set the cache variable, or specify the value of the variable on the cmake command line:

cmake -DFAB:STRING=po

Source: http://cmake.org/cmake/help/v2.8.8/cmake.html#opt:-Dvar:typevalue

Modify your cache variable to a boolean if, in fact, your option is boolean.

httpd Server not started: (13)Permission denied: make_sock: could not bind to address [::]:88

I edited /etc/selinux/config, set SELINUX=disabled, then reboot; then it worked. Alternately, you can run setenforce 0; you don't need reboot, but this is once used.

Read file As String

With files we know the size in advance, so just read it all at once!

String result;
File file = ...;

long length = file.length();
if (length < 1 || length > Integer.MAX_VALUE) {
    result = "";
    Log.w(TAG, "File is empty or huge: " + file);
} else {
    try (FileReader in = new FileReader(file)) {
        char[] content = new char[(int)length];

        int numRead = in.read(content);
        if (numRead != length) {
            Log.e(TAG, "Incomplete read of " + file + ". Read chars " + numRead + " of " + length);
        }
        result = new String(content, 0, numRead);
    }
    catch (Exception ex) {
        Log.e(TAG, "Failure reading " + this.file, ex);
        result = "";
    }
}

Execute Immediate within a stored procedure keeps giving insufficient priviliges error

Oracle's security model is such that when executing dynamic SQL using Execute Immediate (inside the context of a PL/SQL block or procedure), the user does not have privileges to objects or commands that are granted via role membership. Your user likely has "DBA" role or something similar. You must explicitly grant "drop table" permissions to this user. The same would apply if you were trying to select from tables in another schema (such as sys or system) - you would need to grant explicit SELECT privileges on that table to this user.

Git diff says subproject is dirty

Update Jan. 2021, ten years later:

"git diff"(man) showed a submodule working tree with untracked cruft as Submodule commit <objectname>-dirty, but a natural expectation is that the "-dirty" indicator would align with "git describe --dirty"(man), which does not consider having untracked files in the working tree as source of dirtiness.
The inconsistency has been fixed with Git 2.31 (Q1 2021).

See commit 8ef9312 (10 Nov 2020) by Sangeeta Jain (sangu09).
(Merged by Junio C Hamano -- gitster -- in commit 0806279, 25 Jan 2021)

diff: do not show submodule with untracked files as "-dirty"

Signed-off-by: Sangeeta Jain

Git diff reports a submodule directory as -dirty even when there are only untracked files in the submodule directory.
This is inconsistent with what git describe --dirty(man) says when run in the submodule directory in that state.

Make --ignore-submodules=untracked the default for git diff(man) when there is no configuration variable or command line option, so that the command would not give '-dirty' suffix to a submodule whose working tree has untracked files, to make it consistent with git describe --dirty that is run in the submodule working tree.

And also make --ignore-submodules=none the default for git status(man) so that the user doesn't end up deleting a submodule that has uncommitted (untracked) files.

git config now includes in its man page:

By default this is set to untracked so that any untracked submodules are ignored.


Original answer (2011)

As mentioned in Mark Longair's blog post Git Submodules Explained,

Versions 1.7.0 and later of git contain an annoying change in the behavior of git submodule.
Submodules are now regarded as dirty if they have any modified files or untracked files, whereas previously it would only be the case if HEAD in the submodule pointed to the wrong commit.

The meaning of the plus sign (+) in the output of git submodule has changed, and the first time that you come across this it takes a little while to figure out what’s going wrong, for example by looking through changelogs or using git bisect on git.git to find the change. It would have been much kinder to users to introduce a different symbol for “at the specified version, but dirty”.

You can fix it by:

  • either committing or undoing the changes/evolutions within each of your submodules, before going back to the parent repo (where the diff shouldn't report "dirty" files anymore). To undo all changes to your submodule just cd into the root directory of your submodule and do git checkout .

dotnetCarpenter comments that you can do a: git submodule foreach --recursive git checkout .

  • or add --ignore-submodules to your git diff, to temporarily ignore those "dirty" submodules.

New in Git version 1.7.2

As Noam comments below, this question mentions that, since git version 1.7.2, you can ignore the dirty submodules with:

git status --ignore-submodules=dirty

Filtering by Multiple Specific Model Properties in AngularJS (in OR relationship)

I inspired myself from @maxisam's answer and created my own sort function and I'd though I'd share it (cuz I'm bored).

Situation I want to filter through an array of cars. The selected properties to filter are name, year, price and km. The property price and km are numbers (hence the use of .toString). I also want to control for uppercase letters (hence .toLowerCase). Also I want to be able to split up my filter query into different words (e.g. given the filter 2006 Acura, it finds matches 2006 with the year and Acura with the name).

Function I pass to filter

        var attrs = [car.name.toLowerCase(), car.year, car.price.toString(), car.km.toString()],
            filters = $scope.tableOpts.filter.toLowerCase().split(' '),
            isStringInArray = function (string, array){
                for (var j=0;j<array.length;j++){
                    if (array[j].indexOf(string)!==-1){return true;}
                }
                return false;
            };

        for (var i=0;i<filters.length;i++){
            if (!isStringInArray(filters[i], attrs)){return false;}
        }
        return true;
    };

Updating state on props change in React Form

Use Memoize

The op's derivation of state is a direct manipulation of props, with no true derivation needed. In other words, if you have a prop which can be utilized or transformed directly there is no need to store the prop on state.

Given that the state value of start_time is simply the prop start_time.format("HH:mm"), the information contained in the prop is already in itself sufficient for updating the component.

However if you did want to only call format on a prop change, the correct way to do this per latest documentation would be via Memoize: https://reactjs.org/blog/2018/06/07/you-probably-dont-need-derived-state.html#what-about-memoization

ASP.Net MVC: Calling a method from a view

This is how you call an instance method on the Controller:

@{
  ((HomeController)this.ViewContext.Controller).Method1();
}

This is how you call a static method in any class

@{
    SomeClass.Method();
}

This will work assuming the method is public and visible to the view.

Volatile boolean vs AtomicBoolean

volatile keyword guarantees happens-before relationship among threads sharing that variable. It doesn't guarantee you that 2 or more threads won't interrupt each other while accessing that boolean variable.

How do I add indices to MySQL tables?

You say you have an index, the explain says otherwise. However, if you really do, this is how to continue:

If you have an index on the column, and MySQL decides not to use it, it may by because:

  1. There's another index in the query MySQL deems more appropriate to use, and it can use only one. The solution is usually an index spanning multiple columns if their normal method of retrieval is by value of more then one column.
  2. MySQL decides there are to many matching rows, and thinks a tablescan is probably faster. If that isn't the case, sometimes an ANALYZE TABLE helps.
  3. In more complex queries, it decides not to use it based on extremely intelligent thought-out voodoo in the query-plan that for some reason just not fits your current requirements.

In the case of (2) or (3), you could coax MySQL into using the index by index hint sytax, but if you do, be sure run some tests to determine whether it actually improves performance to use the index as you hint it.

Swift's guard keyword

Simply put, it provides a way to validate fields prior to execution. This is a good programming style as it enhances readability. In other languages, it may look like this:

func doSomething() {
    if something == nil {
        // return, break, throw error, etc.
    }
    ...
}

But because Swift provides you with optionals, we can't check if it's nil and assign its value to a variable. In contrast, if let checks that it's not nil and assigns a variable to hold the actual value. This is where guard comes into play. It gives you a more concise way of exiting early using optionals.

How can I get date in application run by node.js?

Node.js is a server side JS platform build on V8 which is chrome java-script runtime.

It leverages the use of java-script on servers too.

You can use JS Date() function or Date class.

How to reverse an animation on mouse out after hover

Try this:

@keyframe in {
from {
    transform: rotate(0deg);
  }
  to {
    transform: rotate(360deg);
  }
}
@keyframe out {
from {
    transform: rotate(360deg);
  }
  to {
    transform: rotate(0deg);
  }
}

supported in Firefox 5+, IE 10+, Chrome, Safari 4+, Opera 12+

Java: Finding the highest value in an array

You need to print out the max after you've scanned all of them:

for (int counter = 1; counter < decMax.length; counter++)
{
    if (decMax[counter] > max)
    {
        max = decMax[counter];
        // not here: System.out.println("The highest maximum for the December is: " + max);
    }
}  
System.out.println("The highest maximum for the December is: " + max);

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

Java installer puts several files into %WinDir%\System32 folder (java.exe, javaws.exe and some others). When you type java.exe in command line or create process without full path, Windows runs these as last resort if they are missing in %PATH% folders.

You can lookup all versions of Java installed in registry. Take a look at HKLM\SOFTWARE\JavaSoft\Java Runtime Environment and HKLM\SOFTWARE\Wow6432Node\JavaSoft\Java Runtime Environment for 32-bit java on 64 bit Windows.

This is how java itself finds out different versions installed. And this is why both 32-bit and 64-bit version can co-exist and works fine without interfering.

Email validation using jQuery

I would recommend Verimail.js, it also has a JQuery plugin.

Why? Verimail supports the following:

  • Syntax validation (according to RFC 822)
  • IANA TLD validation
  • Spelling suggestion for the most common TLDs and email domains
  • Deny temporary email account domains such as mailinator.com

So besides validation, Verimail.js also gives you suggestions. So if you type an email with the wrong TLD or domain that is very similar to a common email domain (hotmail.com, gmail.com, etc), it can detect this and suggest a correction.

Examples:

And so on..

To use it with jQuery, just include verimail.jquery.js on your site and run the function below:

$("input#email-address").verimail({
    messageElement: "p#status-message"
});

The message element is an element in which a message will be shown. This can be everything from "Your email is invalid" to "Did you mean ...?".

If you have a form and want to restrict it so that it cannot be submitted unless the email is valid, then you can check the status using the getVerimailStatus-function as shown below:

if($("input#email-address").getVerimailStatus() < 0){
    // Invalid
}else{
    // Valid
}

This function returns an integer status code according to the object Comfirm.AlphaMail.Verimail.Status. But the general rule of thumb is that any codes below 0 is codes indicating errors.

is there any PHP function for open page in new tab

You can use both PHP and javascript. Perform your php codes in the backend and redirect to a php page. On the php page you redirected to add the code below:

<?php if(condition_to_check_for){ ?>

    <script type="text/javascript">
       window.open('url_goes_here', '_blank');
    </script>

<?  } ?>

Shortcut to Apply a Formula to an Entire Column in Excel

Select a range of cells (the entire column in this case), type in your formula, and hold down Ctrl while you press Enter. This places the formula in all selected cells.

Finding the number of days between two dates

$early_start_date = date2sql($_POST['early_leave_date']);


$date = new DateTime($early_start_date);
$date->modify('+1 day');


$date_a = new DateTime($early_start_date . ' ' . $_POST['start_hr'] . ':' . $_POST['start_mm']);
$date_b = new DateTime($date->format('Y-m-d') . ' ' . $_POST['end_hr'] . ':' . $_POST['end_mm']);

$interval = date_diff($date_a, $date_b);


$time = $interval->format('%h:%i');
$parsed = date_parse($time);
$seconds = $parsed['hour'] * 3600 + $parsed['minute'] * 60;
//        display_error($seconds);

$second3 = $employee_information['shift'] * 60 * 60;

if ($second3 < $seconds)
    display_error(_('Leave time can not be greater than shift time.Please try again........'));
    set_focus('start_hr');
    set_focus('end_hr');
    return FALSE;
}

How to capture the "virtual keyboard show/hide" event in Android?

Not sure if anyone post this. Found this solution simple to use!. The SoftKeyboard class is on gist.github.com. But while keyboard popup/hide event callback we need a handler to properly do things on UI:

/*
Somewhere else in your code
*/
RelativeLayout mainLayout = findViewById(R.layout.main_layout); // You must use your root layout
InputMethodManager im = (InputMethodManager) getSystemService(Service.INPUT_METHOD_SERVICE);

/*
Instantiate and pass a callback
*/
SoftKeyboard softKeyboard;
softKeyboard = new SoftKeyboard(mainLayout, im);
softKeyboard.setSoftKeyboardCallback(new SoftKeyboard.SoftKeyboardChanged()
{

    @Override
    public void onSoftKeyboardHide() 
    {
        // Code here
        new Handler(Looper.getMainLooper()).post(new Runnable() {
                @Override
                public void run() {
                    // Code here will run in UI thread
                    ...
                }
            });
    }

    @Override
    public void onSoftKeyboardShow() 
    {
        // Code here
        new Handler(Looper.getMainLooper()).post(new Runnable() {
                @Override
                public void run() {
                    // Code here will run in UI thread
                    ...
                }
            });

    }   
});

jQuery find and replace string

var string ='my string'
var new_string = string.replace('string','new string');
alert(string);
alert(new_string);

Correct way to pause a Python program

I have had a similar question and I was using signal:

import signal

def signal_handler(signal_number, frame):
    print "Proceed ..."

signal.signal(signal.SIGINT, signal_handler)
signal.pause()

So you register a handler for the signal SIGINT and pause waiting for any signal. Now from outside your program (e.g. in bash), you can run kill -2 <python_pid>, which will send signal 2 (i.e. SIGINT) to your python program. Your program will call your registered handler and proceed running.

How to show what a commit did?

The answers by Bomber and Jakub (Thanks!) are correct and work for me in different situations.

For a quick glance at what was in the commit, I use

git show <replace this with your commit-id>

But I like to view a graphical Diff when studying something in detail and have set up a P4diff as my git diff and then use

git diff <replace this with your commit-id>^!

Re-order columns of table in Oracle

Since the release of Oracle 12c it is now easier to rearrange columns logically.

Oracle 12c added support for making columns invisible and that feature can be used to rearrange columns logically.

Quote from the documentation on invisible columns:

When you make an invisible column visible, the column is included in the table's column order as the last column.

Example

Create a table:

CREATE TABLE t (
    a INT,
    b INT,
    d INT,
    e INT
);

Add a column:

ALTER TABLE t ADD (c INT);

Move the column to the middle:

ALTER TABLE t MODIFY (d INVISIBLE, e INVISIBLE);
ALTER TABLE t MODIFY (d VISIBLE, e VISIBLE);

DESCRIBE t;

Name
----
A
B
C
D
E

Credits

I learned about this from an article by Tom Kyte on new features in Oracle 12c.

How to find and restore a deleted file in a Git repository

In many cases, it can be useful to use coreutils (grep, sed, etc.) in conjunction with Git. I already know these tools quite well, but Git less so. If I wanted to do a search for a deleted file, I would do the following:

git log --raw | grep -B 30 $'D\t.*deleted_file.c'

When I find the revision/commit:

git checkout <rev>^ -- path/to/refound/deleted_file.c

Just like others have stated before me.

The file will now be restored to the state it had before removal. Remember to re-commit it to the working tree if you want to keep it around.

How do I remove version tracking from a project cloned from git?

Windows Command Prompt (cmd) User:

You could delete '.git' recursively inside the source project folder using a single line command.

FOR /F "tokens=*" %G IN ('DIR /B /AD /S *.git*') DO RMDIR /S /Q "%G"

How to manage a redirect request after a jQuery Ajax call

Another solution I found (especially useful if you want to set a global behaviour) is to use the $.ajaxsetup() method together with the statusCode property. Like others pointed out, don't use a redirect statuscode (3xx), instead use a 4xx statuscode and handle the redirect client-side.

$.ajaxSetup({ 
  statusCode : {
    400 : function () {
      window.location = "/";
    }
  }
});

Replace 400 with the statuscode you want to handle. Like already mentioned 401 Unauthorized could be a good idea. I use the 400 since it's very unspecific and I can use the 401 for more specific cases (like wrong login credentials). So instead of redirecting directly your backend should return a 4xx error-code when the session timed out and you you handle the redirect client-side. Works perfect for me even with frameworks like backbone.js

Excel cell value as string won't store as string

Use Range("A1").Text instead of .Value

post comment edit:
Why?
Because the .Text property of Range object returns what is literally visible in the spreadsheet, so if you cell displays for example i100l:25he*_92 then <- Text will return exactly what it in the cell including any formatting.
The .Value and .Value2 properties return what's stored in the cell under the hood excluding formatting. Specially .Value2 for date types, it will return the decimal representation.

If you want to dig deeper into the meaning and performance, I just found this article which seems like a good guide

another edit
Here you go @Santosh
type in (MANUALLY) the values from the DEFAULT (col A) to other columns
Do not format column A at all
Format column B as Text
Format column C as Date[dd/mm/yyyy]
Format column D as Percentage
Dont Format column A, Format B as TEXT, C as Date, D as Percentage
now,
paste this code in a module

Sub main()

    Dim ws As Worksheet, i&, j&
    Set ws = Sheets(1)
    For i = 3 To 7
        For j = 1 To 4
            Debug.Print _
                    "row " & i & vbTab & vbTab & _
                    Cells(i, j).Text & vbTab & _
                    Cells(i, j).Value & vbTab & _
                    Cells(i, j).Value2
        Next j
    Next i
End Sub

and Analyse the output! Its really easy and there isn't much more i can do to help :)

            .TEXT              .VALUE             .VALUE2
row 3       hello             hello               hello
row 3       hello             hello               hello
row 3       hello             hello               hello
row 3       hello             hello               hello
row 4       1                 1                   1
row 4       1                 1                   1
row 4       01/01/1900        31/12/1899          1
row 4       1.00%             0.01                0.01
row 5       helo1$$           helo1$$             helo1$$
row 5       helo1$$           helo1$$             helo1$$
row 5       helo1$$           helo1$$             helo1$$
row 5       helo1$$           helo1$$             helo1$$
row 6       63                63                  63
row 6       =7*9              =7*9                =7*9
row 6       03/03/1900        03/03/1900          63
row 6       6300.00%          63                  63
row 7       29/05/2013        29/05/2013          41423
row 7       29/05/2013        29/05/2013          29/05/2013
row 7       29/05/2013        29/05/2013          41423
row 7       29/05/2013%       29/05/2013%         29/05/2013%

Disable click outside of bootstrap modal area to close modal

This solution worked for me:

$('#myModal').modal({backdrop: 'static', keyboard: false})  

with data-backdrop="static" data-keyboard="false"

in the button witch launch the Modal

How can I open a website in my web browser using Python?

You can simply simply achieve it with any python module that gives you an interaction with command line(cmd) like subprocess, os, etc. but here I came up with examples on only two modules.

Here is syntax (command) cmd /c start browser_name "URL"

Example

import os
# or open with iexplore
os.system('cmd /c start iexplore "http://your_url"')

# or open with chrome
os.system('cmd /c start chrome "http://your_url"')
__import__('subprocess').getoutput('cmd /c start iexplore "http://your_url"')

You can also run the command in the cmd it will work to or use other module call click which mainly used for writing command line utilities.

here is how

import click

click.launch('http://your_url')

How to pass json POST data to Web API method as an object?

Following code to return data in the json format ,instead of the xml -Web API 2 :-

Put following line in the Global.asax file

GlobalConfiguration.Configuration.Formatters.JsonFormatter.SerializerSettings.ReferenceLoopHandling = Newtonsoft.Json.ReferenceLoopHandling.Ignore;
        GlobalConfiguration.Configuration.Formatters.Remove(GlobalConfiguration.Configuration.Formatters.XmlFormatter);

how to check redis instance version?

To get the version of Redis server

redis-server -v

To get the version of Redis client

redis-cli -v

How do I run msbuild from the command line using Windows SDK 7.1?

Using the "Developer Command Prompt for Visual Studio 20XX" instead of "cmd" will set the path for msbuild automatically without having to add it to your environment variables.

How to set value to form control in Reactive Forms in Angular

The "usual" solution is make a function that return an empty formGroup or a fullfilled formGroup

createFormGroup(data:any)
{
 return this.fb.group({
   user: [data?data.user:null],
   questioning: [data?data.questioning:null, Validators.required],
   questionType: [data?data.questionType, Validators.required],
   options: new FormArray([this.createArray(data?data.options:null])
})
}

//return an array of formGroup
createArray(data:any[]|null):FormGroup[]
{
   return data.map(x=>this.fb.group({
        ....
   })
}

then, in SUBSCRIBE, you call the function

this.qService.editQue([params["id"]]).subscribe(res => {
  this.editqueForm = this.createFormGroup(res);
});

be carefull!, your form must include an *ngIf to avoid initial error

<form *ngIf="editqueForm" [formGroup]="editqueForm">
   ....
</form>

How to plot all the columns of a data frame in R

This link helped me a lot for the same problem:

p = ggplot() + 
  geom_line(data = df_plot, aes(x = idx, y = col1), color = "blue") +
  geom_line(data = df_plot, aes(x = idx, y = col2), color = "red") 

print(p)

https://rpubs.com/euclid/343644

How to modify values of JsonObject / JsonArray directly?

Strangely, the answer is to keep adding back the property. I was half expecting a setter method. :S

System.out.println("Before: " + obj.get("DebugLogId")); // original "02352"

obj.addProperty("DebugLogId", "YYY");

System.out.println("After: " + obj.get("DebugLogId")); // now "YYY"

Function to convert column number to letter?

The solution from brettdj works fantastically, but if you are coming across this as a potential solution for the same reason I was, I thought that I would offer my alternative solution.

The problem I was having was scrolling to a specific column based on the output of a MATCH() function. Instead of converting the column number to its column letter parallel, I chose to temporarily toggle the reference style from A1 to R1C1. This way I could just scroll to the column number without having to muck with a VBA function. To easily toggle between the two reference styles, you can use this VBA code:

Sub toggle_reference_style()

If Application.ReferenceStyle = xlR1C1 Then
  Application.ReferenceStyle = xlA1
Else
  Application.ReferenceStyle = xlR1C1
End If

End Sub

How to create new div dynamically, change it, move it, modify it in every way possible, in JavaScript?

Have you tried JQuery? Vanilla javascript can be tough. Try using this:

$('.container-element').add('<div>Insert Div Content</div>');

.container-element is a JQuery selector that marks the element with the class "container-element" (presumably the parent element in which you want to insert your divs). Then the add() function inserts HTML into the container-element.

Render HTML to PDF in Django site

After trying to get this to work for too many hours, I finally found this: https://github.com/vierno/django-xhtml2pdf

It's a fork of https://github.com/chrisglass/django-xhtml2pdf that provides a mixin for a generic class-based view. I used it like this:

    # views.py
    from django_xhtml2pdf.views import PdfMixin
    class GroupPDFGenerate(PdfMixin, DetailView):
        model = PeerGroupSignIn
        template_name = 'groups/pdf.html'

    # templates/groups/pdf.html
    <html>
    <style>
    @page { your xhtml2pdf pisa PDF parameters }
    </style>
    </head>
    <body>
        <div id="header_content"> (this is defined in the style section)
            <h1>{{ peergroupsignin.this_group_title }}</h1>
            ...

Use the model name you defined in your view in all lowercase when populating the template fields. Because its a GCBV, you can just call it as '.as_view' in your urls.py:

    # urls.py (using url namespaces defined in the main urls.py file)
    url(
        regex=r"^(?P<pk>\d+)/generate_pdf/$",
        view=views.GroupPDFGenerate.as_view(),
        name="generate_pdf",
       ),

How to run a command in the background on Windows?

You should also take a look at the at command in Windows. It will launch a program at a certain time in the background which works in this case.

Another option is to use the nssm service manager software. This will wrap whatever command you are running as a windows service.

UPDATE:

nssm isn't very good. You should instead look at WinSW project. https://github.com/kohsuke/winsw

*.h or *.hpp for your class definitions

It does not matter which extension you use. Either one is OK.

I use *.h for C and *.hpp for C++.

Unsuccessful append to an empty NumPy array

numpy.append is pretty different from list.append in python. I know that's thrown off a few programers new to numpy. numpy.append is more like concatenate, it makes a new array and fills it with the values from the old array and the new value(s) to be appended. For example:

import numpy

old = numpy.array([1, 2, 3, 4])
new = numpy.append(old, 5)
print old
# [1, 2, 3, 4]
print new
# [1, 2, 3, 4, 5]
new = numpy.append(new, [6, 7])
print new
# [1, 2, 3, 4, 5, 6, 7]

I think you might be able to achieve your goal by doing something like:

result = numpy.zeros((10,))
result[0:2] = [1, 2]

# Or
result = numpy.zeros((10, 2))
result[0, :] = [1, 2]

Update:

If you need to create a numpy array using loop, and you don't know ahead of time what the final size of the array will be, you can do something like:

import numpy as np

a = np.array([0., 1.])
b = np.array([2., 3.])

temp = []
while True:
    rnd = random.randint(0, 100)
    if rnd > 50:
        temp.append(a)
    else:
        temp.append(b)
    if rnd == 0:
         break

 result = np.array(temp)

In my example result will be an (N, 2) array, where N is the number of times the loop ran, but obviously you can adjust it to your needs.

new update

The error you're seeing has nothing to do with types, it has to do with the shape of the numpy arrays you're trying to concatenate. If you do np.append(a, b) the shapes of a and b need to match. If you append an (2, n) and (n,) you'll get a (3, n) array. Your code is trying to append a (1, 0) to a (2,). Those shapes don't match so you get an error.

How to use filter, map, and reduce in Python 3

from functools import reduce

def f(x):
    return x % 2 != 0 and x % 3 != 0

print(*filter(f, range(2, 25)))
#[5, 7, 11, 13, 17, 19, 23]

def cube(x):
    return x**3
print(*map(cube, range(1, 11)))
#[1, 8, 27, 64, 125, 216, 343, 512, 729, 1000]

def add(x,y):
    return x+y

reduce(add, range(1, 11))
#55

It works as is. To get the output of map use * or list

What is the best way to get the minimum or maximum value from an Array of numbers?

There isn't any reliable way to get the minimum/maximum without testing every value. You don't want to try a sort or anything like that, walking through the array is O(n), which is better than any sort algorithm can do in the general case.

Eclipse: Syntax Error, parameterized types are only if source level is 1.5

Do the following..

Right-click on your project--> select properties-----> select Java Compilers

You wills see this window

Image for reference

Now check the checkbox ---> enable project specific settings.

Now set the compiler compliance level to 1.6

Apply then Ok

now clean your project and you are good to go

Bootstrap Columns Not Working

While this does not address the OP's question, I had trouble with my bootstrap rows / columns while trying to use them in conjunction with Kendo ListView (even with the bootstrap-kendo css).

Adding the following css fixed the problem for me:

#myListView.k-widget, #catalog-items.k-widget * {
    -webkit-box-sizing: border-box;
    box-sizing: border-box;
}

PHP MySQL Query Where x = $variable

What you are doing right now is you are adding . on the string and not concatenating. It should be,

$result = mysqli_query($con,"SELECT `note` FROM `glogin_users` WHERE email = '".$email."'");

or simply

$result = mysqli_query($con,"SELECT `note` FROM `glogin_users` WHERE email = '$email'");

Angular.js: set element height on page load

angular.element(document).ready(function () {
    //your logic here
});

How to Call a Function inside a Render in React/Jsx

To call the function you have to add ()

{this.renderIcon()}   

How to compare LocalDate instances Java 8

LocalDate ld ....;
LocalDateTime ldtime ...;

ld.isEqual(LocalDate.from(ldtime));

How do I format XML in Notepad++?

The location of XML tools has changed slightly since this question was first asked.

I am currently using Notepad++ v7.8.6

New location is:

  • Plugins tab
  • Plugins Admin...
  • Plugins Admin dialog appears with Available plugins tab as the default
  • Scroll to the bottom and check the XML Tools checkbox
  • Click Install button in top right of the dialog

This will close Notepad++ while it installs and then restart it automatically.

Then there are a couple keyboard shortcuts to beautify the XML:

  • Pretty Print: Ctrl + Shift + Alt + B
  • Pretty Print (indent attributes): Ctrl + Shift + Alt + A

To see more XML Tools options:

  • Plugins tab
  • XML Tools option

Scroll RecyclerView to show selected item on top

what i did to restore the scroll position after refreshing the RecyclerView on button clicked:

if (linearLayoutManager != null) {

    index = linearLayoutManager.findFirstVisibleItemPosition();
    View v = linearLayoutManager.getChildAt(0);
    top = (v == null) ? 0 : (v.getTop() - linearLayoutManager.getPaddingTop());
    Log.d("TAG", "visible position " + " " + index);
}

else{
    index = 0;
}

linearLayoutManager = new LinearLayoutManager(getApplicationContext());
linearLayoutManager.scrollToPositionWithOffset(index, top);

getting the offset of the first visible item from the top before creating the linearLayoutManager object and after instantiating it the scrollToPositionWithOffset of the LinearLayoutManager object was called.

Base64 encoding in SQL Server 2005 T-SQL

I know this has already been answered, but I just spent more time than I care to admit coming up with single-line SQL statements to accomplish this, so I'll share them here in case anyone else needs to do the same:

-- Encode the string "TestData" in Base64 to get "VGVzdERhdGE="
SELECT
    CAST(N'' AS XML).value(
          'xs:base64Binary(xs:hexBinary(sql:column("bin")))'
        , 'VARCHAR(MAX)'
    )   Base64Encoding
FROM (
    SELECT CAST('TestData' AS VARBINARY(MAX)) AS bin
) AS bin_sql_server_temp;

-- Decode the Base64-encoded string "VGVzdERhdGE=" to get back "TestData"
SELECT 
    CAST(
        CAST(N'' AS XML).value(
            'xs:base64Binary("VGVzdERhdGE=")'
          , 'VARBINARY(MAX)'
        ) 
        AS VARCHAR(MAX)
    )   ASCIIEncoding
;

I had to use a subquery-generated table in the first (encoding) query because I couldn't find any way to convert the original value ("TestData") to its hex string representation ("5465737444617461") to include as the argument to xs:hexBinary() in the XQuery statement.

I hope this helps someone!

Mysql command not found in OS X 10.7

Your PATH might not setup. Go to terminal and type:

echo 'export PATH="/usr/local/mysql/bin:$PATH"' >> ~/.bash_profile

Essentially, this allows you to access mysql from anywhere.

Type cat .bash_profile to check the PATH has been setup.

Check mysql version now: mysql --version

If this still doesn't work, close the terminal and reopen. Check the version now, it should work. Good luck!

Python: Get HTTP headers from urllib2.urlopen call?

urllib2.urlopen does an HTTP GET (or POST if you supply a data argument), not an HTTP HEAD (if it did the latter, you couldn't do readlines or other accesses to the page body, of course).

What is the difference between Task.Run() and Task.Factory.StartNew()

People already mentioned that

Task.Run(A);

Is equivalent to

Task.Factory.StartNew(A, CancellationToken.None, TaskCreationOptions.DenyChildAttach, TaskScheduler.Default);

But no one mentioned that

Task.Factory.StartNew(A);

Is equivalent to:

Task.Factory.StartNew(A, CancellationToken.None, TaskCreationOptions.None, TaskScheduler.Current);

As you can see two parameters are different for Task.Run and Task.Factory.StartNew:

  1. TaskCreationOptions - Task.Run uses TaskCreationOptions.DenyChildAttach which means that children tasks can not be attached to the parent, consider this:

    var parentTask = Task.Run(() =>
    {
        var childTask = new Task(() =>
        {
            Thread.Sleep(10000);
            Console.WriteLine("Child task finished.");
        }, TaskCreationOptions.AttachedToParent);
        childTask.Start();
    
        Console.WriteLine("Parent task finished.");
    });
    
    parentTask.Wait();
    Console.WriteLine("Main thread finished.");
    

    When we invoke parentTask.Wait(), childTask will not be awaited, even though we specified TaskCreationOptions.AttachedToParent for it, this is because TaskCreationOptions.DenyChildAttach forbids children to attach to it. If you run the same code with Task.Factory.StartNew instead of Task.Run, parentTask.Wait() will wait for childTask because Task.Factory.StartNew uses TaskCreationOptions.None

  2. TaskScheduler - Task.Run uses TaskScheduler.Default which means that the default task scheduler (the one that runs tasks on Thread Pool) will always be used to run tasks. Task.Factory.StartNew on the other hand uses TaskScheduler.Current which means scheduler of the current thread, it might be TaskScheduler.Default but not always. In fact when developing Winforms or WPF applications it is required to update UI from the current thread, to do this people use TaskScheduler.FromCurrentSynchronizationContext() task scheduler, if you unintentionally create another long running task inside task that used TaskScheduler.FromCurrentSynchronizationContext() scheduler the UI will be frozen. A more detailed explanation of this can be found here

So generally if you are not using nested children task and always want your tasks to be executed on Thread Pool it is better to use Task.Run, unless you have some more complex scenarios.

Hibernate error - QuerySyntaxException: users is not mapped [from users]

You must type in the same name in your select query as your entity or class(case sensitive) . i.e. select user from className/Entity Name user;

How do I get and set Environment variables in C#?

This will work for an environment variable that is machine setting. For Users, just change to User instead.

String EnvironmentPath = System.Environment
                .GetEnvironmentVariable("Variable_Name", EnvironmentVariableTarget.Machine);

How to select specific columns in laravel eloquent

You can also use find() like this:

ModelName::find($id, ['name', 'surname']);

The $id variable can be an array in case you need to retrieve multiple instances of the model.

How to modify a CSS display property from JavaScript?

CSS properties should be set by cssText property or setAttribute method.

// Set multiple styles in a single statement
elt.style.cssText = "color: blue; border: 1px solid black"; 
// Or
elt.setAttribute("style", "color:red; border: 1px solid blue;");

Styles should not be set by assigning a string directly to the style property (as in elt.style = "color: blue;"), since it is considered read-only, as the style attribute returns a CSSStyleDeclaration object which is also read-only.

How do I pass parameters into a PHP script through a webpage?

Presumably you're passing the arguments in on the command line as follows:

php /path/to/wwwpublic/path/to/script.php arg1 arg2

... and then accessing them in the script thusly:

<?php
// $argv[0] is '/path/to/wwwpublic/path/to/script.php'
$argument1 = $argv[1];
$argument2 = $argv[2];
?>

What you need to be doing when passing arguments through HTTP (accessing the script over the web) is using the query string and access them through the $_GET superglobal:

Go to http://yourdomain.com/path/to/script.php?argument1=arg1&argument2=arg2

... and access:

<?php
$argument1 = $_GET['argument1'];
$argument2 = $_GET['argument2'];
?>

If you want the script to run regardless of where you call it from (command line or from the browser) you'll want something like the following:

EDIT: as pointed out by Cthulhu in the comments, the most direct way to test which environment you're executing in is to use the PHP_SAPI constant. I've updated the code accordingly:

<?php
if (PHP_SAPI === 'cli') {
    $argument1 = $argv[1];
    $argument2 = $argv[2];
}
else {
    $argument1 = $_GET['argument1'];
    $argument2 = $_GET['argument2'];
}
?>

Locate current file in IntelliJ

In Intellij Idea Community edition 2020.1 :

  1. Right click on project header
  2. Select 'Always Select Opened File'

enter image description here

convert 12-hour hh:mm AM/PM to 24-hour hh:mm

An extended version of @krzysztof answer with the ability to work on time that has space or not between time and modifier.

const convertTime12to24 = (time12h) => {
      const [fullMatch, time, modifier] = time12h.match(/(\d?\d:\d\d)\s*(\w{2})/i);

      let [hours, minutes] = time.split(':');

      if (hours === '12') {
        hours = '00';
      }

      if (modifier === 'PM') {
        hours = parseInt(hours, 10) + 12;
      }

      return `${hours}:${minutes}`;
    }

    console.log(convertTime12to24('01:02 PM'));
    console.log(convertTime12to24('05:06 PM'));
    console.log(convertTime12to24('12:00 PM'));
    console.log(convertTime12to24('12:00 AM'));

What is the difference between 'E', 'T', and '?' for Java generics?

It's more convention than anything else.

  • T is meant to be a Type
  • E is meant to be an Element (List<E>: a list of Elements)
  • K is Key (in a Map<K,V>)
  • V is Value (as a return value or mapped value)

They are fully interchangeable (conflicts in the same declaration notwithstanding).

System.Threading.Timer in C# it seems to be not working. It runs very fast every 3 second

This is not the correct usage of the System.Threading.Timer. When you instantiate the Timer, you should almost always do the following:

_timer = new Timer( Callback, null, TIME_INTERVAL_IN_MILLISECONDS, Timeout.Infinite );

This will instruct the timer to tick only once when the interval has elapsed. Then in your Callback function you Change the timer once the work has completed, not before. Example:

private void Callback( Object state )
{
    // Long running operation
   _timer.Change( TIME_INTERVAL_IN_MILLISECONDS, Timeout.Infinite );
}

Thus there is no need for locking mechanisms because there is no concurrency. The timer will fire the next callback after the next interval has elapsed + the time of the long running operation.

If you need to run your timer at exactly N milliseconds, then I suggest you measure the time of the long running operation using Stopwatch and then call the Change method appropriately:

private void Callback( Object state )
{
   Stopwatch watch = new Stopwatch();

   watch.Start();
   // Long running operation

   _timer.Change( Math.Max( 0, TIME_INTERVAL_IN_MILLISECONDS - watch.ElapsedMilliseconds ), Timeout.Infinite );
}

I strongly encourage anyone doing .NET and is using the CLR who hasn't read Jeffrey Richter's book - CLR via C#, to read is as soon as possible. Timers and thread pools are explained in great details there.

Changing Fonts Size in Matlab Plots

Jonas's answer is good, but I had to modify it slightly to get every piece of text on the screen to change:

set(gca,'FontSize',30,'fontWeight','bold')

set(findall(gcf,'type','text'),'FontSize',30,'fontWeight','bold')

CSS selector (id contains part of text)

<div id='element_123_wrapper_text'>My sample DIV</div>

The Operator ^ - Match elements that starts with given value

div[id^="element_123"] {

}

The Operator $ - Match elements that ends with given value

div[id$="wrapper_text"] {

}

The Operator * - Match elements that have an attribute containing a given value

div[id*="wrapper_text"] {

}

How to reload the datatable(jquery) data?

You can use a simple approach...

$('YourDataTableID').dataTable()._fnAjaxUpdate();

It will refresh the data by making an ajax request with the same parameters. Very simple.

SQL statement to select all rows from previous day

subdate(now(),1) will return yesterdays timestamp The below code will select all rows with yesterday's timestamp

Select * FROM `login` WHERE `dattime` <= subdate(now(),1) AND `dattime` > subdate(now(),2)

What does the Java assert keyword do, and when should it be used?

Assertion are basically used to debug the application or it is used in replacement of exception handling for some application to check the validity of an application.

Assertion works at run time. A simple example, that can explain the whole concept very simply, is herein - What does the assert keyword do in Java? (WikiAnswers).

Returning multiple values from a C++ function

It's entirely dependent upon the actual function and the meaning of the multiple values, and their sizes:

  • If they're related as in your fraction example, then I'd go with a struct or class instance.
  • If they're not really related and can't be grouped into a class/struct then perhaps you should refactor your method into two.
  • Depending upon the in-memory size of the values you're returning, you may want to return a pointer to a class instance or struct, or use reference parameters.

Error 0x80005000 and DirectoryServices

This Error can occur if the physical machine has run out of memory. In my case i was hosting a site on IIS trying to access the AD, but the server had run out of memory.

How to globally replace a forward slash in a JavaScript string?

Hi a small correction in the above script.. above script skipping the first character when displaying the output.

function stripSlashes(x)
{
var y = "";
for(i = 0; i < x.length; i++)
{
    if(x.charAt(i) == "/")
    {
        y += "";
    }
    else
    {
        y+= x.charAt(i);
    }
}
return y;   
}

Is there functionality to generate a random character in Java?

polygenelubricants' answer is also a good solution if you only want to generate Hex values:

/** A list of all valid hexadecimal characters. */
private static char[] HEX_VALUES = { '0', '1', '2', '3', '4', '5', '6', '7', '8', '9', '0', 'A', 'B', 'C', 'D', 'E', 'F' };

/** Random number generator to be used to create random chars. */
private static Random RANDOM = new SecureRandom();

/**
 * Creates a number of random hexadecimal characters.
 * 
 * @param nValues the amount of characters to generate
 * 
 * @return an array containing <code>nValues</code> hex chars
 */
public static char[] createRandomHexValues(int nValues) {
    char[] ret = new char[nValues];
    for (int i = 0; i < nValues; i++) {
        ret[i] = HEX_VALUES[RANDOM.nextInt(HEX_VALUES.length)];
    }
    return ret;
}

Difference between long and int data types

A typical best practice is not using long/int/short directly. Instead, according to specification of compilers and OS, wrap them into a header file to ensure they hold exactly the amount of bits that you want. Then use int8/int16/int32 instead of long/int/short. For example, on 32bit Linux, you could define a header like this

typedef char int8;
typedef short int16;
typedef int int32;
typedef unsigned int uint32;

React Native android build failed. SDK location not found

If you create and android studio project, You can see a local.properties file is created inside your project root directory. When you create a react native project, It doesn't create that file for you. So you have to create it manually. And have to add skd dir to it. So create a new file inside android folder ( on root ). and put your sdk path like this sdk.dir=D\:\\Android\\SDK\\android_sdk_studio . Remember: remove single \ with double. Just like above.

When is it practical to use Depth-First Search (DFS) vs Breadth-First Search (BFS)?

According to the properties of DFS and BFS. For example,when we want to find the shortest path. we usually use bfs,it can guarantee the 'shortest'. but dfs only can guarantee that we can come from this point can achieve that point ,can not guarantee the 'shortest'.

How to set MimeBodyPart ContentType to "text/html"?

There is a method setText() which takes 3 arguments :

public void setText(String text, String charset, String subtype)
    throws MessagingException

Parameters:

text - the text content to set
charset - the charset to use for the text
subtype - the MIME subtype to use (e.g., "html")

NOTE: the subtype takes text after / in MIME types so for ex.

  • text/html would be html
  • text/css would be css
  • and so on..

How to prevent line breaks in list items using CSS

Bootstrap 4 has a class named text-nowrap. It is just what you need.

combining results of two select statements

Probably you use Microsoft SQL Server which support Common Table Expressions (CTE) (see http://msdn.microsoft.com/en-us/library/ms190766.aspx) which are very friendly for query optimization. So I suggest you my favor construction:

WITH GetNumberOfPlans(Id,NumberOfPlans) AS (
    SELECT tableA.Id, COUNT(tableC.Id)
    FROM tableC
        RIGHT OUTER JOIN tableA ON tableC.tableAId = tableA.Id
    GROUP BY tableA.Id
),GetUserInformation(Id,Name,Owner,ImageUrl,
                     CompanyImageUrl,NumberOfUsers) AS (
    SELECT tableA.Id, tableA.Name, tableB.Username AS Owner, tableB.ImageUrl,
        tableB.CompanyImageUrl,COUNT(tableD.UserId),p.NumberOfPlans
    FROM tableA
        INNER JOIN tableB ON tableB.Id = tableA.Owner
        RIGHT OUTER JOIN tableD ON tableD.tableAId = tableA.Id
    GROUP BY tableA.Name, tableB.Username, tableB.ImageUrl, tableB.CompanyImageUrl
)
SELECT u.Id,u.Name,u.Owner,u.ImageUrl,u.CompanyImageUrl
    ,u.NumberOfUsers,p.NumberOfPlans
FROM GetUserInformation AS u
    INNER JOIN GetNumberOfPlans AS p ON p.Id=u.Id

After some experiences with CTE you will be find very easy to write code using CTE and you will be happy with the performance.

Convert a JSON String to a HashMap

Convert using Jackson :

JSONObject obj = new JSONObject().put("abc", "pqr").put("xyz", 5);

Map<String, Object> map = new ObjectMapper().readValue(obj.toString(), new TypeReference<Map<String, Object>>() {});

How to get the device's IMEI/ESN programmatically in android?

use below code:

if (Build.VERSION.SDK_INT >= Build.VERSION_CODES.M) {
        String[] permissions = {Manifest.permission.READ_PHONE_STATE};
        if (ActivityCompat.checkSelfPermission(this,
                Manifest.permission.READ_PHONE_STATE) != PackageManager.PERMISSION_GRANTED) {
            requestPermissions(permissions, READ_PHONE_STATE);
        }
    } else {
        try {
            TelephonyManager telephonyManager = (TelephonyManager) getSystemService(Context.TELEPHONY_SERVICE);
            if (ActivityCompat.checkSelfPermission(this, Manifest.permission.READ_PHONE_STATE) != PackageManager.PERMISSION_GRANTED) {
                return;
            }
            String imei = telephonyManager.getDeviceId();

        } catch (Exception e) {
            e.printStackTrace();
        }
    }

And call onRequestPermissionsResult method following code:

@Override
public void onRequestPermissionsResult(int requestCode, @NonNull String[] permissions, @NonNull int[] grantResults) {
    switch (requestCode) {
        case READ_PHONE_STATE:
            if (grantResults.length > 0
                    && grantResults[0] == PackageManager.PERMISSION_GRANTED)
                try {
                    TelephonyManager telephonyManager = (TelephonyManager) getSystemService(Context.TELEPHONY_SERVICE);
                    if (ActivityCompat.checkSelfPermission(this, Manifest.permission.READ_PHONE_STATE) != PackageManager.PERMISSION_GRANTED) {
                        return;
                    }
                    String imei = telephonyManager.getDeviceId();

                } catch (Exception e) {
                    e.printStackTrace();
                }
    }
}

Add following permission in your AndroidManifest.xml:

<uses-permission android:name="android.permission.READ_PHONE_STATE" />

How to delete a character from a string using Python

You can simply use list comprehension.

Assume that you have the string: my name is and you want to remove character m. use the following code:

"".join([x for x in "my name is" if x is not 'm'])

Javascript equivalent of php's strtotime()?

Yes, it is. And it is supported in all major browser:

var ts = Date.parse("date string");

The only difference is that this function returns milliseconds instead of seconds, so you need to divide the result by 1000.

Check what valid formats can JavaScript parse.

Excel compare two columns and highlight duplicates

The easiest way to do it, at least for me, is:

Conditional format-> Add new rule->Set your own formula:

=ISNA(MATCH(A2;$B:$B;0))

Where A2 is the first element in column A to be compared and B is the column where A's element will be searched.

Once you have set the formula and picked the format, apply this rule to all elements in the column.

Hope this helps

Is there a way to iterate over a range of integers?

The problem is not the range, the problem is how the end of slice is calculated. with a fixed number 10 the simple for loop is ok but with a calculated size like bfl.Size() you get a function-call on every iteration. A simple range over int32 would help because this evaluate the bfl.Size() only once.

type BFLT PerfServer   
  func (this *BFLT) Call() {
    bfl := MqBufferLCreateTLS(0)                                                                                   
    for this.ReadItemExists() {                                                                                    
      bfl.AppendU(this.ReadU())                                                                                    
    }
    this.SendSTART()
    // size := bfl.Size() 
    for i := int32(0); i < bfl.Size() /* size */; i++ {                                                                             
      this.SendU(bfl.IndexGet(i))                                                                                  
    }
    this.SendRETURN()
  }

Save file to specific folder with curl command

curl doesn't have an option to that (without also specifying the filename), but wget does. The directory can be relative or absolute. Also, the directory will automatically be created if it doesn't exist.

wget -P relative/dir "$url"

wget -P /absolute/dir "$url"

Adding css class through aspx code behind

BtnAdd.CssClass = "BtnCss";

BtnCss should be present in your Css File.

(reference of that Css File name should be added to the aspx if needed)

How do I select an element in jQuery by using a variable for the ID?

There are two problems with your code

  1. To find an element by ID you must prefix it with a "#"
  2. You are attempting to pass a Number to the find function when a String is required (passing "#" + 5 would fix this as it would convert the 5 to a "5" first)

log4net hierarchy and logging levels

Here is some code telling about priority of all log4net levels:

TraceLevel(Level.All); //-2147483648

TraceLevel(Level.Verbose);   //  10 000
TraceLevel(Level.Finest);    //  10 000
    
TraceLevel(Level.Trace);     //  20 000
TraceLevel(Level.Finer);     //  20 000
    
TraceLevel(Level.Debug);     //  30 000
TraceLevel(Level.Fine);      //  30 000
    
TraceLevel(Level.Info);      //  40 000
TraceLevel(Level.Notice);    //  50 000
    
TraceLevel(Level.Warn);      //  60 000
TraceLevel(Level.Error);     //  70 000
TraceLevel(Level.Severe);    //  80 000
TraceLevel(Level.Critical);  //  90 000
TraceLevel(Level.Alert);     // 100 000
TraceLevel(Level.Fatal);     // 110 000
TraceLevel(Level.Emergency); // 120 000
    
TraceLevel(Level.Off); //2147483647


private static void TraceLevel(log4net.Core.Level level)
{
   Debug.WriteLine("{0} = {1}", level, level.Value);
}

How to trim a file extension from a String in JavaScript?

In node.js, the name of the file without the extension can be obtained as follows.

const path = require('path');
const filename = 'hello.html';
    
path.parse(filename).name;     //=> "hello"
path.parse(filename).ext;      //=> ".html"
path.parse(filename).base; //=> "hello.html"

Further explanation at Node.js documentation page.

Convert this string to datetime

The Problem is with your code formatting,

inorder to use strtotime() You should replace '06/Oct/2011:19:00:02' with 06/10/2011 19:00:02 and date('d/M/Y:H:i:s', $date); with date('d/M/Y H:i:s', $date);. Note the spaces in between.

So the final code looks like this

$s = '06/10/2011 19:00:02';
$date = strtotime($s);
echo date('d/M/Y H:i:s', $date);

How to delete Certain Characters in a excel 2010 cell

Another option: =MID(A1,2,LEN(A1)-2)

Or this (for fun): =RIGHT(LEFT(A1,LEN(A1)-1),LEN(LEFT(A1,LEN(A1)-1))-1)

Fix height of a table row in HTML Table

my css

TR.gray-t {background:#949494;}
h3{
    padding-top:3px;
    font:bold 12px/2px Arial;
}

my html

<TR class='gray-t'>
<TD colspan='3'><h3>KAJANG</h3>

I decrease the 2nd size in font.

padding-top is used to fix the size in IE7.

How to use HTML to print header and footer on every printed page of a document?

I have been searching for years for a solution and found this post on how to print a footer that works on multiple pages without overlapping page content.

My requirement was IE8, so far I have found that this does not work in Chrome. [update]As of 1 March 2018, it works in Chrome as well

This example uses tables and the tfoot element by setting the css style:

tfoot {display: table-footer-group;}

How do I display the current value of an Android Preference in the Preference summary?

Actually, CheckBoxPreference does have the ability to specify a different summary based on the checkbox value. See the android:summaryOff and android:summaryOn attributes (as well as the corresponding CheckBoxPreference methods).

'^M' character at end of lines

Another vi command that'll do: :%s/.$// This removes the last character of each line in the file. The drawback to this search and replace command is that it doesn't care what the last character is, so be careful not to call it twice.

JavaScript/jQuery - "$ is not defined- $function()" error

Im using Asp.Net Core 2.2 with MVC and Razor cshtml My JQuery is referenced in a layout page I needed to add the following to my view.cshtml:

@section Scripts {
$script-here
}

Javascript/jQuery detect if input is focused

Did you try:

$(this).is(':focus');

Take a look at Using jQuery to test if an input has focus it features some more examples

Call to a member function fetch_assoc() on boolean in <path>

OK, i just fixed this error.

This happens when there is an error in query or table doesn't exist.

Try debugging the query buy running it directly on phpmyadmin to confirm the validity of the mysql Query

React Native Responsive Font Size

Need to use this way I have used this one and it's working fine.

react-native-responsive-screen npm install react-native-responsive-screen --save

Just like I have a device 1080x1920

The vertical number we calculate from height **hp**
height:200
200/1920*100 = 10.41% - height:hp("10.41%")


The Horizontal number we calculate from width **wp**
width:200
200/1080*100 = 18.51% - Width:wp("18.51%")

It's working for all device