SyntaxFix

Programs & Examples On #Xfa

XFA stands for XML Forms Architecture, a family of proprietary XML specifications that was suggested and developed by JetForm to enhance the processing of web forms. It can be also used in PDF files starting with PDF 1.5 specification. XML Forms Architecture was not standardized as an ISO standard

LDAP: error code 49 - 80090308: LdapErr: DSID-0C0903A9, comment: AcceptSecurityContext error, data 52e, v1db1

LDAP is trying to authenticate with AD when sending a transaction to another server DB. This authentication fails because the user has recently changed her password, although this transaction was generated using the previous credentials. This authentication will keep failing until ... unless you change the transaction status to Complete or Cancel in which case LDAP will stop sending these transactions.

How to use hex() without 0x in Python?

Old style string formatting:

In [3]: "%02x" % 127
Out[3]: '7f'

New style

In [7]: '{:x}'.format(127)
Out[7]: '7f'

Using capital letters as format characters yields uppercase hexadecimal

In [8]: '{:X}'.format(127)
Out[8]: '7F'

Docs are here.

LDAP Authentication using Java

Following Code authenticates from LDAP using pure Java JNDI. The Principle is:-

  1. First Lookup the user using a admin or DN user.
  2. The user object needs to be passed to LDAP again with the user credential
  3. No Exception means - Authenticated Successfully. Else Authentication Failed.

Code Snippet

public static boolean authenticateJndi(String username, String password) throws Exception{
    Properties props = new Properties();
    props.put(Context.INITIAL_CONTEXT_FACTORY, "com.sun.jndi.ldap.LdapCtxFactory");
    props.put(Context.PROVIDER_URL, "ldap://LDAPSERVER:PORT");
    props.put(Context.SECURITY_PRINCIPAL, "uid=adminuser,ou=special users,o=xx.com");//adminuser - User with special priviledge, dn user
    props.put(Context.SECURITY_CREDENTIALS, "adminpassword");//dn user password


    InitialDirContext context = new InitialDirContext(props);

    SearchControls ctrls = new SearchControls();
    ctrls.setReturningAttributes(new String[] { "givenName", "sn","memberOf" });
    ctrls.setSearchScope(SearchControls.SUBTREE_SCOPE);

    NamingEnumeration<javax.naming.directory.SearchResult> answers = context.search("o=xx.com", "(uid=" + username + ")", ctrls);
    javax.naming.directory.SearchResult result = answers.nextElement();

    String user = result.getNameInNamespace();

    try {
        props = new Properties();
        props.put(Context.INITIAL_CONTEXT_FACTORY, "com.sun.jndi.ldap.LdapCtxFactory");
        props.put(Context.PROVIDER_URL, "ldap://LDAPSERVER:PORT");
        props.put(Context.SECURITY_PRINCIPAL, user);
        props.put(Context.SECURITY_CREDENTIALS, password);

   context = new InitialDirContext(props);
    } catch (Exception e) {
        return false;
    }
    return true;
}

Ajax request returns 200 OK, but an error event is fired instead of success

Your script demands a return in JSON data type.

Try this:

private string test() {
  JavaScriptSerializer js = new JavaScriptSerializer();
 return js.Serialize("hello world");
}

How do a LDAP search/authenticate against this LDAP in Java

Another approach is using UnboundID. Its api is very readable and shorter

Create a Ldap Connection

public static LDAPConnection getConnection() throws LDAPException {
    // host, port, username and password
    return new LDAPConnection("com.example.local", 389, "[email protected]", "admin");
}

Get filter result

public static List<SearchResultEntry> getResults(LDAPConnection connection, String baseDN, String filter) throws LDAPSearchException {
    SearchResult searchResult;

    if (connection.isConnected()) {
        searchResult = connection.search(baseDN, SearchScope.ONE, filter);

        return searchResult.getSearchEntries();
    }

    return null;
}

Get all Oragnization Units and Containers

String baseDN = "DC=com,DC=example,DC=local";
String filter = "(&(|(objectClass=organizationalUnit)(objectClass=container)))";

LDAPConnection connection = getConnection();        
List<SearchResultEntry> results = getResults(connection, baseDN, filter);

Get a specific Organization Unit

String baseDN = "DC=com,DC=example,DC=local";
String dn = "CN=Users,DC=com,DC=example,DC=local";

String filterFormat = "(&(|(objectClass=organizationalUnit)(objectClass=container))(distinguishedName=%s))";
String filter = String.format(filterFormat, dn);

LDAPConnection connection =  getConnection();

List<SearchResultEntry> results = getResults(connection, baseDN, filter);

Get all users under an Organizational Unit

String baseDN = "CN=Users,DC=com,DC=example,DC=local";
String filter = "(&(objectClass=user)(!(objectCategory=computer)))";

LDAPConnection connection =  getConnection();       
List<SearchResultEntry> results = getResults(connection, baseDN, filter);

Get a specific user under an Organization Unit

String baseDN = "CN=Users,DC=com,DC=example,DC=local";
String userDN = "CN=abc,CN=Users,DC=com,DC=example,DC=local";

String filterFormat = "(&(objectClass=user)(distinguishedName=%s))";
String filter = String.format(filterFormat, userDN);

LDAPConnection connection =  getConnection();
List<SearchResultEntry> results = getResults(connection, baseDN, filter);

Display result

for (SearchResultEntry e : results) {
    System.out.println("name: " + e.getAttributeValue("name"));
}

Pass Multiple Parameters to jQuery ajax call

 
    var valueOfTextBox=$("#result").val();
    var valueOfSelectedCheckbox=$("#radio:checked").val();

    $.ajax({
    url: 'result.php',
    type: 'POST',
    data: { forValue: valueOfTextBox, check : valueOfSelectedCheckbox } ,
    beforeSend: function() {

          $("#loader").show();
       },
    success: function (response) {
       $("#loader").hide();
       $("#answer").text(response);
    },
    error: function () {
        //$("#loader").show();
        alert("error occured");
    }
    });

Where do I find the current C or C++ standard documents?

PDF versions of the standard

As of 1st September 2014, the best locations by price for C and C++ standards documents in PDF are:

You cannot usually get old revisions of a standard (any standard) directly from the standards bodies shortly after a new edition of the standard is released. Thus, standards for C89, C90, C99, C++98, C++03 will be hard to find for purchase from a standards body. If you need an old revision of a standard, check Techstreet as one possible source. For example, it can still provide the Canadian version CAN/CSA-ISO/IEC 9899:1990 standard in PDF, for a fee.

Non-PDF electronic versions of the standard

Print versions of the standard

Print copies of the standards are available from national standards bodies and ISO but are very expensive.

If you want a hardcopy of the C90 standard for much less money than above, you may be able to find a cheap used copy of Herb Schildt's book The Annotated ANSI Standard at Amazon, which contains the actual text of the standard (useful) and commentary on the standard (less useful - it contains several dangerous and misleading errors).

The C99 and C++03 standards are available in book form from Wiley and the BSI (British Standards Institute):

Standards committee draft versions (free)

The working drafts for future standards are often available from the committee websites:

If you want to get drafts from the current or earlier C/C++ standards, there are some available for free on the internet:

For C:

(Almost the same as ANSI X3.159-198 (C89) except for the frontmatter and section numbering. Note that the conversion between ANSI and ISO/IEC Standard is seen inside this document, the document refers to its name as "ANSI/ISO: 9899/99" although this isn't the right name of the later made standard of it, the right name is "ISO/IEC 9899:1990")

For C++:

Note that these documents are not the same as the standard, though the versions just prior to the meetings that decide on a standard are usually very close to what is in the final standard. The FCD (Final Committee Draft) versions are password protected; you need to be on the standards committee to get them.

Even though the draft versions might be very close to the final ratified versions of the standards, some of this post's editors would strongly advise you to get a copy of the actual documents — especially if you're planning on quoting them as references. Of course, starving students should go ahead and use the drafts if strapped for cash.

It appears that, if you are willing and able to wait a few months after ratification of a standard, to search for "INCITS/ISO/IEC" instead of "ISO/IEC" when looking for a standard is the key. By doing so, one of this post's editors was able to find the C11 and C++11 standards at reasonable prices. For example, if you search for "INCITS/ISO/IEC 9899:2011" instead of "ISO/IEC 9899:2011" on webstore.ansi.org you will find the reasonably priced PDF version.

The site https://wg21.link/ provides short-URL links to the C++ current working draft and draft standards, and committee papers:

The current draft of the standard is maintained as LaTeX sources on Github. These sources can be converted to HTML using cxxdraft-htmlgen. The following sites maintain HTML pages so generated:

Tim Song also maintains generated HTML and PDF versions of the Networking TS and Ranges TS.

Write and read a list from file

As long as your file has consistent formatting (i.e. line-breaks), this is easy with just basic file IO and string operations:

with open('my_file.txt', 'rU') as in_file:
    data = in_file.read().split('\n')

That will store your data file as a list of items, one per line. To then put it into a file, you would do the opposite:

with open('new_file.txt', 'w') as out_file:
    out_file.write('\n'.join(data)) # This will create a string with all of the items in data separated by new-line characters

Hopefully that fits what you're looking for.

How to get all of the IDs with jQuery?

The best way I can think of to answer this is to make a custom jquery plugin to do this:

jQuery.fn.getIdArray = function() {
  var ret = [];
  $('[id]', this).each(function() {
    ret.push(this.id);
  });
  return ret;
};

Then do something like 

var array = $("#mydiv").getIdArray();

Run script with rc.local: script works, but not at boot

In this example of a rc.local script I use io redirection at the very first line of execution to my own log file:

#!/bin/sh -e
#
# rc.local
#
# This script is executed at the end of each multiuser runlevel.
# Make sure that the script will "exit 0" on success or any other
# value on error.
#
# In order to enable or disable this script just change the execution
# bits.
#
# By default this script does nothing.

exec 2> /tmp/rc.local.log  # send stderr from rc.local to a log file
exec 1>&2                      # send stdout to the same log file
set -x                         # tell sh to display commands before execution

/opt/stuff/somefancy.error.script.sh

exit 0

Determine Whether Integer Is Between Two Other Integers?

There are two ways to compare three integers and check whether b is between a and c:

if a < b < c:
    pass

and

if a < b and b < c:
    pass

The first one looks like more readable, but the second one runs faster.

Let's compare using dis.dis:

>>> dis.dis('a < b and b < c')
  1           0 LOAD_NAME                0 (a)
              2 LOAD_NAME                1 (b)
              4 COMPARE_OP               0 (<)
              6 JUMP_IF_FALSE_OR_POP    14
              8 LOAD_NAME                1 (b)
             10 LOAD_NAME                2 (c)
             12 COMPARE_OP               0 (<)
        >>   14 RETURN_VALUE
>>> dis.dis('a < b < c')
  1           0 LOAD_NAME                0 (a)
              2 LOAD_NAME                1 (b)
              4 DUP_TOP
              6 ROT_THREE
              8 COMPARE_OP               0 (<)
             10 JUMP_IF_FALSE_OR_POP    18
             12 LOAD_NAME                2 (c)
             14 COMPARE_OP               0 (<)
             16 RETURN_VALUE
        >>   18 ROT_TWO
             20 POP_TOP
             22 RETURN_VALUE
>>>

and using timeit:

~$ python3 -m timeit "1 < 2 and 2 < 3"
10000000 loops, best of 3: 0.0366 usec per loop

~$ python3 -m timeit "1 < 2 < 3"
10000000 loops, best of 3: 0.0396 usec per loop

also, you may use range, as suggested before, however it is much more slower.

Scala check if element is present in a list

And if you didn't want to use strict equality, you could use exists:


myFunction(strings.exists { x => customPredicate(x) })

Xcode couldn't find any provisioning profiles matching

You can get this issue if Apple update their terms. Simply log into your dev account and accept any updated terms and you should be good (you will need to goto Xcode -> project->signing and capabilities and retry the certificate check. This should get you going if terms are the issue.

How can I get new selection in "select" in Angular 2?

Just use [ngValue] instead of [value]!!

export class Organisation {
  description: string;
  id: string;
  name: string;
}
export class ScheduleComponent implements OnInit {
  selectedOrg: Organisation;
  orgs: Organisation[] = [];

  constructor(private organisationService: OrganisationService) {}

  get selectedOrgMod() {
    return this.selectedOrg;
  }

  set selectedOrgMod(value) {
    this.selectedOrg = value;
  }
}


<div class="form-group">
      <label for="organisation">Organisation
      <select id="organisation" class="form-control" [(ngModel)]="selectedOrgMod" required>
        <option *ngFor="let org of orgs" [ngValue]="org">{{org.name}}</option>
      </select>
      </label>
</div>

Swift - encode URL

None of these answers worked for me. Our app was crashing when a url contained non-English characters.

 let unreserved = "-._~/?%$!:"
 let allowed = NSMutableCharacterSet.alphanumeric()
     allowed.addCharacters(in: unreserved)

 let escapedString = urlString.addingPercentEncoding(withAllowedCharacters: allowed as CharacterSet)

Depending on the parameters of what you are trying to do, you may want to just create your own character set. The above allows for english characters, and -._~/?%$!:

Adding an assets folder in Android Studio

An image of how to in Android Studio 1.5.1.

Within the "Android" project (see the drop-down in the topleft of my image), Right-click on the app...

enter image description here

print memory address of Python variable

There is no way to get the memory address of a value in Python 2.7 in general. In Jython or PyPy, the implementation doesn't even know your value's address (and there's not even a guarantee that it will stay in the same place—e.g., the garbage collector is allowed to move it around if it wants).

However, if you only care about CPython, id is already returning the address. If the only issue is how to format that integer in a certain way… it's the same as formatting any integer:

>>> hex(33)
0x21
>>> '{:#010x}'.format(33) # 32-bit
0x00000021
>>> '{:#018x}'.format(33) # 64-bit
0x0000000000000021

… and so on.

However, there's almost never a good reason for this. If you actually need the address of an object, it's presumably to pass it to ctypes or similar, in which case you should use ctypes.addressof or similar.

Open button in new window?

If you strictly want to stick to using button,Then simply create an open window function as follows:

    <script>
function myfunction() {
    window.open("mynewpage.html");
}
</script>

Then in your html do the following with your button:

Join

So you would have something like this:

 <body>
    <script>
function joinfunction() {
    window.open("mynewpage.html");
}
</script>
<button  onclick="myfunction()" type="button" class="btn btn-default subs-btn">Join</button>

Javascript: How to remove the last character from a div or a string?

 
var string = "Hello";
var str = string.substring(0, string.length-1);
alert(str);

http://jsfiddle.net/d72ML/

How to get N rows starting from row M from sorted table in T-SQL

Probably good for small results, works in all versions of TSQL:

SELECT 
        * 
FROM
     (SELECT TOP (N) * 
      FROM 
            (SELECT TOP (M + N - 1) 
             FROM 
                   Table
             ORDER BY 
                      MyColumn) qasc
      ORDER BY 
               MyColumn DESC) qdesc
 ORDER BY 
         MyColumn

Reading *.wav files in Python

If you're going to perform transfers on the waveform data then perhaps you should use SciPy, specifically scipy.io.wavfile.

Sublime 3 - Set Key map for function Goto Definition

On a mac you have to set keybinding yourself. Simply go to 

Sublime --> Preference --> Key Binding - User

and input the following:

{ "keys": ["shift+command+m"], "command": "goto_definition" }

This will enable keybinding of Shift + Command + M to enable goto definition. You can set the keybinding to anything you would like of course.

Cocoa Autolayout: content hugging vs content compression resistance priority

contentCompressionResistancePriority – The view with the lowest value gets truncated when there is not enough space to fit everything’s intrinsicContentSize

contentHuggingPriority – The view with the lowest value gets expanded beyond its intrinsicContentSize when there is leftover space to fill

Copying files from one directory to another in Java

Java 8

Path sourcepath = Paths.get("C:\\data\\temp\\mydir");
Path destinationepath = Paths.get("C:\\data\\temp\\destinationDir");        
Files.walk(sourcepath)
         .forEach(source -> copy(source, destinationepath.resolve(sourcepath.relativize(source))));

Copy Method

static void copy(Path source, Path dest) {
    try {
        Files.copy(source, dest, StandardCopyOption.REPLACE_EXISTING);
    } catch (Exception e) {
        throw new RuntimeException(e.getMessage(), e);
    }
}

How to get integer values from a string in Python?

An answer taken from ChristopheD here: https://stackoverflow.com/a/2500023/1225603

r = "456results string789"
s = ''.join(x for x in r if x.isdigit())
print int(s)
456789

If strings starts with in PowerShell

$Group is an object, but you will actually need to check if $Group.samaccountname.StartsWith("string").

Change $Group.StartsWith("S_G_") to $Group.samaccountname.StartsWith("S_G_").

ORA-00918: column ambiguously defined in SELECT *

A query's projection can only have one instance of a given name. As your WHERE clause shows, you have several tables with a column called ID. Because you are selecting * your projection will have several columns called ID. Or it would have were it not for the compiler hurling ORA-00918.

The solution is quite simple: you will have to expand the projection to explicitly select named columns. Then you can either leave out the duplicate columns, retaining just (say) COACHES.ID or use column aliases: coaches.id as COACHES_ID.

Perhaps that strikes you as a lot of typing, but it is the only way. If it is any comfort, SELECT * is regarded as bad practice in production code: explicitly named columns are much safer.

How can I represent a range in Java?

You could create a class to represent this

public class Range
{
    private int low;
    private int high;

    public Range(int low, int high){
        this.low = low;
        this.high = high;
    }

    public boolean contains(int number){
        return (number >= low && number <= high);
    }
}

Sample usage:

Range range = new Range(0, 2147483647);

if (range.contains(foo)) {
    //do something
}

jQuery Get Selected Option From Dropdown

Just this should work:

var conceptName = $('#aioConceptName').val();

How do you underline a text in Android XML?

If you want to compare text String or the text will change dynamically then you can created a view in Constraint layout it will adjust according to text length like this

 <android.support.constraint.ConstraintLayout
    android:layout_width="match_parent"
    android:layout_height="wrap_content">

    <TextView
        android:id="@+id/txt_Previous"
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:layout_marginStart="16dp"
        android:layout_marginLeft="16dp"
        android:layout_marginEnd="16dp"
        android:layout_marginRight="16dp"
        android:layout_marginBottom="8dp"
        android:gravity="center"
        android:text="Last Month Rankings"
        android:textColor="@color/colorBlue"
        android:textSize="15sp"
        android:textStyle="bold"
        app:layout_constraintBottom_toBottomOf="parent"
        app:layout_constraintEnd_toEndOf="parent"
        app:layout_constraintStart_toStartOf="parent" />

    <View
        android:layout_width="0dp"
        android:layout_height="0.7dp"
        android:background="@color/colorBlue"
        app:layout_constraintEnd_toEndOf="@+id/txt_Previous"
        app:layout_constraintStart_toStartOf="@+id/txt_Previous"
        app:layout_constraintBottom_toBottomOf="@id/txt_Previous"/>


</android.support.constraint.ConstraintLayout>

TABLOCK vs TABLOCKX

Big difference, TABLOCK will try to grab "shared" locks, and TABLOCKX exclusive locks.

If you are in a transaction and you grab an exclusive lock on a table, EG:

SELECT 1 FROM TABLE WITH (TABLOCKX)

No other processes will be able to grab any locks on the table, meaning all queries attempting to talk to the table will be blocked until the transaction commits.

TABLOCK only grabs a shared lock, shared locks are released after a statement is executed if your transaction isolation is READ COMMITTED (default). If your isolation level is higher, for example: SERIALIZABLE, shared locks are held until the end of a transaction.

Shared locks are, hmmm, shared. Meaning 2 transactions can both read data from the table at the same time if they both hold a S or IS lock on the table (via TABLOCK). However, if transaction A holds a shared lock on a table, transaction B will not be able to grab an exclusive lock until all shared locks are released. Read about which locks are compatible with which at msdn.

Both hints cause the db to bypass taking more granular locks (like row or page level locks). In principle, more granular locks allow you better concurrency. So for example, one transaction could be updating row 100 in your table and another row 1000, at the same time from two transactions (it gets tricky with page locks, but lets skip that).

In general granular locks is what you want, but sometimes you may want to reduce db concurrency to increase performance of a particular operation and eliminate the chance of deadlocks.

In general you would not use TABLOCK or TABLOCKX unless you absolutely needed it for some edge case.

update package.json version automatically

Just in case if you want to do this using an npm package semver link

let fs = require('fs');
let semver = require('semver');

if (fs.existsSync('./package.json')) {
    var package = require('./package.json');
    let currentVersion = package.version;
    let type = process.argv[2];
    if (!['major', 'minor', 'patch'].includes(type)) {
        type = 'patch';
    }

    let newVersion = semver.inc(package.version, type);
    package.version = newVersion;
    fs.writeFileSync('./package.json', JSON.stringify(package, null, 2));

    console.log('Version updated', currentVersion, '=>', newVersion);
}

package.json should look like,

{
  "name": "versioning",
  "version": "0.0.0",
  "description": "Update version in package.json using npm script",
  "main": "version.js",
  "scripts": {
    "test": "echo \"Error: no test specified\" && exit 1",
    "version": "node version.js"
  },
  "author": "Bhadresh Arya",
  "license": "ISC",
  "dependencies": {
    "semver": "^7.3.2"
  }
}

just pass major, minor, patch argument with npm run version. Default will be patch.

example: npm run version or npm run verison patch or npm run verison minor or npm run version major

Git Repo

Partition Function COUNT() OVER possible using DISTINCT

I use a solution that is similar to that of David above, but with an additional twist if some rows should be excluded from the count. This assumes that [UserAccountKey] is never null.

-- subtract an extra 1 if null was ranked within the partition,
-- which only happens if there were rows where [Include] <> 'Y'
dense_rank() over (
  partition by [Mth] 
  order by case when [Include] = 'Y' then [UserAccountKey] else null end asc
) 
+ dense_rank() over (
  partition by [Mth] 
  order by case when [Include] = 'Y' then [UserAccountKey] else null end desc
)
- max(case when [Include] = 'Y' then 0 else 1 end) over (partition by [Mth])
- 1

An SQL Fiddle with an extended example can be found here.

How to write string literals in python without having to escape them?

(Assuming you are not required to input the string from directly within Python code)

to get around the Issue Andrew Dalke pointed out, simply type the literal string into a text file and then use this;

input_ = '/directory_of_text_file/your_text_file.txt' 
input_open   = open(input_,'r+')
input_string = input_open.read()

print input_string

This will print the literal text of whatever is in the text file, even if it is;

 '   ''' """  “ \

Not fun or optimal, but can be useful, especially if you have 3 pages of code that would’ve needed character escaping.

Make DateTimePicker work as TimePicker only in WinForms

...or alternatively if you only want to show a portion of the time value use "Custom":

timePicker = new DateTimePicker();
timePicker.Format = DateTimePickerFormat.Custom;
timePicker.CustomFormat = "HH:mm"; // Only use hours and minutes
timePicker.ShowUpDown = true;

Get time in milliseconds using C#

Use the Stopwatch class.

Provides a set of methods and properties that you can use to accurately measure elapsed time.

There is some good info on implementing it here:

Performance Tests: Precise Run Time Measurements with System.Diagnostics.Stopwatch

Change the Arrow buttons in Slick slider

The Best way i Found to do that is this. You can remove my HTML and place yours there.

$('.home-banner-slider').slick({
    dots: false,
    infinite: true,
    autoplay: true,
    autoplaySpeed: 3000,
    speed: 300,
    slidesToScroll: 1,
    arrows: true,
    prevArrow: '<div class="slick-prev"><i class="fa fa-angle-left" aria-hidden="true"></i></div>',
    nextArrow: '<div class="slick-next"><i class="fa fa-angle-right" aria-hidden="true"></i></div>'
});

Cannot find module cv2 when using OpenCV

This happens when python cannot refer to your default site-packages folder where you have kept the required python files or libraries

Add these lines in the code:

import sys

sys.path.append('/usr/local/lib/python2.7/site-packages')

or before running the python command in bash move to /usr/local/lib/python2.7/site-packages directory. This is a work around if you don't want to add any thing to the code.

SqlException: DB2 SQL error: SQLCODE: -302, SQLSTATE: 22001, SQLERRMC: null

As a general point when using a search engine to search for SQL codes make sure you put the sqlcode e.g. -302 in quote marks - like "-302" otherwise the search engine will exclude all search results including the text 302, since the - sign is used to exclude results.

How to set cache: false in jQuery.get call

Per the JQuery documentation, .get() only takes the url, data (content), dataType, and success callback as its parameters. What you're really looking to do here is modify the jqXHR object before it gets sent. With .ajax(), this is done with the beforeSend() method. But since .get() is a shortcut, it doesn't allow it.

It should be relatively easy to switch your .ajax() calls to .get() calls though. After all, .get() is just a subset of .ajax(), so you can probably use all the default values for .ajax() (except, of course, for beforeSend()).

Edit:

::Looks at Jivings' answer::

Oh yeah, forgot about the cache parameter! While beforeSend() is useful for adding other headers, the built-in cache parameter is far simpler here.

Process list on Linux via Python

 
import os
lst = os.popen('sudo netstat -tulpn').read()
lst = lst.split('\n')
for i in range(2,len(lst)):
    print(lst[i])

Accept server's self-signed ssl certificate in Java client

You have basically two options here: add the self-signed certificate to your JVM truststore or configure your client to

Option 1

Export the certificate from your browser and import it in your JVM truststore (to establish a chain of trust):

<JAVA_HOME>\bin\keytool -import -v -trustcacerts
-alias server-alias -file server.cer
-keystore cacerts.jks -keypass changeit
-storepass changeit

Option 2

Disable Certificate Validation:

// Create a trust manager that does not validate certificate chains
TrustManager[] trustAllCerts = new TrustManager[] { 
    new X509TrustManager() {     
        public java.security.cert.X509Certificate[] getAcceptedIssuers() { 
            return new X509Certificate[0];
        } 
        public void checkClientTrusted( 
            java.security.cert.X509Certificate[] certs, String authType) {
            } 
        public void checkServerTrusted( 
            java.security.cert.X509Certificate[] certs, String authType) {
        }
    } 
}; 

// Install the all-trusting trust manager
try {
    SSLContext sc = SSLContext.getInstance("SSL"); 
    sc.init(null, trustAllCerts, new java.security.SecureRandom()); 
    HttpsURLConnection.setDefaultSSLSocketFactory(sc.getSocketFactory());
} catch (GeneralSecurityException e) {
} 
// Now you can access an https URL without having the certificate in the truststore
try { 
    URL url = new URL("https://hostname/index.html"); 
} catch (MalformedURLException e) {
}

Note that I do not recommend the Option #2 at all. Disabling the trust manager defeats some parts of SSL and makes you vulnerable to man in the middle attacks. Prefer Option #1 or, even better, have the server use a "real" certificate signed by a well known CA.

Android Fragment onAttach() deprecated

Although it seems that in most cases it's enough to have onAttach(Context), there are some phones (i.e: Xiaomi Redme Note 2) where it's not being called, thus it causes NullPointerExceptions. So to be on the safe side I suggest to leave the deprecated method as well:

// onAttach(Activity) is necessary in some Xiaomi phones
@SuppressWarnings("deprecation")
@Override
public void onAttach(Activity activity) {
    super.onAttach(activity);
    _onAttach(activity);
}

@Override
public void onAttach(Context context) {
    super.onAttach(context);
    _onAttach(context);
}

private void _onAttach(Context context) {
    // do your real stuff here
}

Show Console in Windows Application?

Easiest way is to start a WinForms application, go to settings and change the type to a console application.

Post form data using HttpWebRequest

Both the field name and the value should be url encoded. format of the post data and query string are the same

The .net way of doing is something like this

NameValueCollection outgoingQueryString = HttpUtility.ParseQueryString(String.Empty);
outgoingQueryString.Add("field1","value1");
outgoingQueryString.Add("field2", "value2");
string postdata = outgoingQueryString.ToString();

This will take care of encoding the fields and the value names

Python Pandas Error tokenizing data

you could also try;

data = pd.read_csv('file1.csv', error_bad_lines=False)

Do note that this will cause the offending lines to be skipped.

Opening database file from within SQLite command-line shell

Older SQLite command-line shells (sqlite3.exe) do not appear to offer the .open command or any readily identifiable alternative.

Although I found no definitive reference it seems that the .open command was introduced around version 3.15. The SQLite Release History first mentions the .open command with 2016-10-14 (3.15.0).

Encoding URL query parameters in Java

It is not necessary to encode a colon as %3B in the query, although doing so is not illegal.

URI         = scheme ":" hier-part [ "?" query ] [ "#" fragment ]
query       = *( pchar / "/" / "?" )
pchar         = unreserved / pct-encoded / sub-delims / ":" / "@"
unreserved    = ALPHA / DIGIT / "-" / "." / "_" / "~"
pct-encoded   = "%" HEXDIG HEXDIG
sub-delims    = "!" / "$" / "&" / "'" / "(" / ")" / "*" / "+" / "," / ";" / "="

It also seems that only percent-encoded spaces are valid, as I doubt that space is an ALPHA or a DIGIT

look to the URI specification for more details.

Angular 4 setting selected option in Dropdown

If you want to select a value based on true / false use

[selected]="opt.selected == true"

 <option *ngFor="let opt of question.options" [value]="opt.key" [selected]="opt.selected == true">{{opt.selected+opt.value}}</option>

checkit out

Angular 2 - Setting selected value on dropdown list

Why doesn't os.path.join() work in this case?

To make your function more portable, use it as such:

os.path.join(os.sep, 'home', 'build', 'test', 'sandboxes', todaystr, 'new_sandbox')

or

os.path.join(os.environ.get("HOME"), 'test', 'sandboxes', todaystr, 'new_sandbox')

INSERT VALUES WHERE NOT EXISTS

More of a comment link for suggested further reading...A really good blog article which benchmarks various ways of accomplishing this task can be found here.

They use a few techniques: "Insert Where Not Exists", "Merge" statement, "Insert Except", and your typical "left join" to see which way is the fastest to accomplish this task.

The example code used for each technique is as follows (straight copy/paste from their page) :

INSERT INTO #table1 (Id, guidd, TimeAdded, ExtraData)
SELECT Id, guidd, TimeAdded, ExtraData
FROM #table2
WHERE NOT EXISTS (Select Id, guidd From #table1 WHERE #table1.id = #table2.id)
-----------------------------------
MERGE #table1 as [Target]
USING  (select Id, guidd, TimeAdded, ExtraData from #table2) as [Source]
(id, guidd, TimeAdded, ExtraData)
    on [Target].id =[Source].id
WHEN NOT MATCHED THEN
    INSERT (id, guidd, TimeAdded, ExtraData)
    VALUES ([Source].id, [Source].guidd, [Source].TimeAdded, [Source].ExtraData);
------------------------------
INSERT INTO #table1 (id, guidd, TimeAdded, ExtraData)
SELECT id, guidd, TimeAdded, ExtraData from #table2
EXCEPT
SELECT id, guidd, TimeAdded, ExtraData from #table1
------------------------------
INSERT INTO #table1 (id, guidd, TimeAdded, ExtraData)
SELECT #table2.id, #table2.guidd, #table2.TimeAdded, #table2.ExtraData
FROM #table2
LEFT JOIN #table1 on #table1.id = #table2.id
WHERE #table1.id is null

It's a good read for those who are looking for speed! On SQL 2014, the Insert-Except method turned out to be the fastest for 50 million or more records.

Limit Decimal Places in Android EditText

The simplest way to achieve that is:

et.addTextChangedListener(new TextWatcher() {
    public void onTextChanged(CharSequence arg0, int arg1, int arg2, int arg3) {
        String text = arg0.toString();
        if (text.contains(".") && text.substring(text.indexOf(".") + 1).length() > 2) {
            et.setText(text.substring(0, text.length() - 1));
            et.setSelection(et.getText().length());
        }
    }

    public void beforeTextChanged(CharSequence arg0, int arg1, int arg2, int arg3) {

    }

    public void afterTextChanged(Editable arg0) {
    }
});

Perform Segue programmatically and pass parameters to the destination view

The answer is simply that it makes no difference how the segue is triggered.

The prepareForSegue:sender: method is called in any case and this is where you pass your parameters across.

How to define hash tables in Bash?

Bash 4

Bash 4 natively supports this feature. Make sure your script's hashbang is #!/usr/bin/env bash or #!/bin/bash so you don't end up using sh. Make sure you're either executing your script directly, or execute script with bash script. (Not actually executing a Bash script with Bash does happen, and will be really confusing!)

You declare an associative array by doing:

declare -A animals

You can fill it up with elements using the normal array assignment operator. For example, if you want to have a map of animal[sound(key)] = animal(value):

animals=( ["moo"]="cow" ["woof"]="dog")

Or merge them:

declare -A animals=( ["moo"]="cow" ["woof"]="dog")

Then use them just like normal arrays. Use

  • animals['key']='value' to set value

  • "${animals[@]}" to expand the values

  • "${!animals[@]}" (notice the !) to expand the keys

Don't forget to quote them:

echo "${animals[moo]}"
for sound in "${!animals[@]}"; do echo "$sound - ${animals[$sound]}"; done

Bash 3

Before bash 4, you don't have associative arrays. Do not use eval to emulate them. Avoid eval like the plague, because it is the plague of shell scripting. The most important reason is that eval treats your data as executable code (there are many other reasons too).

First and foremost: Consider upgrading to bash 4. This will make the whole process much easier for you.

If there's a reason you can't upgrade, declare is a far safer option. It does not evaluate data as bash code like eval does, and as such does not allow arbitrary code injection quite so easily.

Let's prepare the answer by introducing the concepts:

First, indirection.

$ animals_moo=cow; sound=moo; i="animals_$sound"; echo "${!i}"
cow

Secondly, declare:

$ sound=moo; animal=cow; declare "animals_$sound=$animal"; echo "$animals_moo"
cow

Bring them together:

# Set a value:
declare "array_$index=$value"

# Get a value:
arrayGet() { 
    local array=$1 index=$2
    local i="${array}_$index"
    printf '%s' "${!i}"
}

Let's use it:

$ sound=moo
$ animal=cow
$ declare "animals_$sound=$animal"
$ arrayGet animals "$sound"
cow

Note: declare cannot be put in a function. Any use of declare inside a bash function turns the variable it creates local to the scope of that function, meaning we can't access or modify global arrays with it. (In bash 4 you can use declare -g to declare global variables - but in bash 4, you can use associative arrays in the first place, avoiding this workaround.)

Summary:

  • Upgrade to bash 4 and use declare -A for associative arrays.
  • Use the declare option if you can't upgrade.
  • Consider using awk instead and avoid the issue altogether.

fatal error LNK1112: module machine type 'x64' conflicts with target machine type 'X86'

for some using command prompt (dos prompt) this might be helpful:

call "C:\Program Files (x86)\Microsoft Visual Studio 14.0\VC\vcvarsall.bat" --help
Error in script usage. The correct usage is:
    "C:\Program Files (x86)\Microsoft Visual Studio 14.0\VC\vcvarsall.bat" [option]
  or
    "C:\Program Files (x86)\Microsoft Visual Studio 14.0\VC\vcvarsall.bat" [option] store
  or
    "C:\Program Files (x86)\Microsoft Visual Studio 14.0\VC\vcvarsall.bat" [option] [version number]
  or
    "C:\Program Files (x86)\Microsoft Visual Studio 14.0\VC\vcvarsall.bat" [option] store [version number]
where [option] is: x86 | amd64 | arm | x86_amd64 | x86_arm | amd64_x86 | amd64_arm
where [version number] is either the full Windows 10 SDK version number or "8.1" to use the windows 8.1 SDK
:
The store parameter sets environment variables to support
  store (rather than desktop) development.
:
For example:
    "C:\Program Files (x86)\Microsoft Visual Studio 14.0\VC\vcvarsall.bat" x86_amd64
    "C:\Program Files (x86)\Microsoft Visual Studio 14.0\VC\vcvarsall.bat" x86_arm store
    "C:\Program Files (x86)\Microsoft Visual Studio 14.0\VC\vcvarsall.bat" x86_amd64 10.0.10240.0
    "C:\Program Files (x86)\Microsoft Visual Studio 14.0\VC\vcvarsall.bat" x86_arm store 10.0.10240.0
    "C:\Program Files (x86)\Microsoft Visual Studio 14.0\VC\vcvarsall.bat" x64 8.1
    "C:\Program Files (x86)\Microsoft Visual Studio 14.0\VC\vcvarsall.bat" x64 store 8.1
:
Please make sure either Visual Studio or C++ Build SKU is installed.

Also If you do like this:

CL "%1%2%3" /EHsc /link user32.lib Gdi32.lib Winmm.lib comctl32.lib *.obj /SUBSYSTEM:CONSOLE /MACHINE:x86

you have to del *.obj before; to avoid confusing linker with both 64 and 32 bit objects left over from prior compilations?

I want my android application to be only run in portrait mode?

I use

 android:screenOrientation="nosensor"

It is helpful if you do not want to support up side down portrait mode.

How to make MySQL handle UTF-8 properly

Update:

Short answer - You should almost always be using the utf8mb4 charset and utf8mb4_unicode_ci collation.

To alter database:

ALTER DATABASE dbname CHARACTER SET utf8mb4 COLLATE utf8mb4_unicode_ci;

See:

Original Answer:

MySQL 4.1 and above has a default character set of UTF-8. You can verify this in your my.cnf file, remember to set both client and server (default-character-set and character-set-server).

If you have existing data that you wish to convert to UTF-8, dump your database, and import it back as UTF-8 making sure:

  • use SET NAMES utf8 before you query/insert into the database
  • use DEFAULT CHARSET=utf8 when creating new tables
  • at this point your MySQL client and server should be in UTF-8 (see my.cnf). remember any languages you use (such as PHP) must be UTF-8 as well. Some versions of PHP will use their own MySQL client library, which may not be UTF-8 aware.

If you do want to migrate existing data remember to backup first! Lots of weird choping of data can happen when things don't go as planned!

Some resources:

How to run a jar file in a linux commandline

For example to execute from terminal (Ubuntu Linux) or even (Windows console) a java file called filex.jar use this command:

java -jar filex.jar

The file will execute in terminal.

How to dump only specific tables from MySQL?

 
Usage: mysqldump [OPTIONS] database [tables]

i.e.

mysqldump -u username -p db_name table1_name table2_name table3_name > dump.sql

Tensorflow import error: No module named 'tensorflow'

Since none of the above solve my issue, I will post my solution

WARNING: if you just installed TensorFlow using conda, you have to restart your command prompt!

Solution: restart terminal ENTIRELY and restart conda environment

Send POST data on redirect with JavaScript/jQuery?

This is quite handy to use:

var myRedirect = function(redirectUrl, arg, value) {
  var form = $('<form action="' + redirectUrl + '" method="post">' +
  '<input type="hidden" name="'+ arg +'" value="' + value + '"></input>' + '</form>');
  $('body').append(form);
  $(form).submit();
};

then use it like: 

myRedirect("/yourRedirectingUrl", "arg", "argValue");

How to check string length and then select substring in Sql Server

To conditionally check the length of the string, use CASE.

SELECT  CASE WHEN LEN(comments) <= 60 
             THEN comments
             ELSE LEFT(comments, 60) + '...'
        END  As Comments
FROM    myView

HTML text input field with currency symbol

If you only need to support Safari, you can do it like this:

input.currency:before {
  content: attr(data-symbol);
  float: left;
  color: #aaa;
}

and an input field like

<input class="currency" data-symbol="€" type="number" value="12.9">

This way you don't need an extra tag and keep the symbol information in the markup.

C++ Array of pointers: delete or delete []?

delete[] monsters is definitely wrong. My heap debugger shows the following output:

allocated non-array memory at 0x3e38f0 (20 bytes)
allocated non-array memory at 0x3e3920 (20 bytes)
allocated non-array memory at 0x3e3950 (20 bytes)
allocated non-array memory at 0x3e3980 (20 bytes)
allocated non-array memory at 0x3e39b0 (20 bytes)
allocated non-array memory at 0x3e39e0 (20 bytes)
releasing     array memory at 0x22ff38

As you can see, you are trying to release with the wrong form of delete (non-array vs. array), and the pointer 0x22ff38 has never been returned by a call to new. The second version shows the correct output:

[allocations omitted for brevity]
releasing non-array memory at 0x3e38f0
releasing non-array memory at 0x3e3920
releasing non-array memory at 0x3e3950
releasing non-array memory at 0x3e3980
releasing non-array memory at 0x3e39b0
releasing non-array memory at 0x3e39e0

Anyway, I prefer a design where manually implementing the destructor is not necessary to begin with.

#include <array>
#include <memory>

class Foo
{
    std::array<std::shared_ptr<Monster>, 6> monsters;

    Foo()
    {
        for (int i = 0; i < 6; ++i)
        {
            monsters[i].reset(new Monster());
        }
    }

    virtual ~Foo()
    {
        // nothing to do manually
    }
};

Android: Proper Way to use onBackPressed() with Toast

I use this much simpler approach...

public class XYZ extends Activity {
    private long backPressedTime = 0;    // used by onBackPressed()


    @Override
    public void onBackPressed() {        // to prevent irritating accidental logouts
        long t = System.currentTimeMillis();
        if (t - backPressedTime > 2000) {    // 2 secs
            backPressedTime = t;
            Toast.makeText(this, "Press back again to logout",
                                Toast.LENGTH_SHORT).show();
        } else {    // this guy is serious
            // clean up
            super.onBackPressed();       // bye
        }
    }
}

Hash function that produces short hashes?

It is now 2019 and there are better options. Namely, xxhash.

~ echo test | xxhsum                                                           
2d7f1808da1fa63c  stdin

Debugging WebSocket in Google Chrome

They seem to continuously change stuff in Chrome, but here's what works right now :-)

  • First you must click on the red record button or you'll get nothing.

  • I never noticed the WS before but it filters out the web socket connections.

  • Select it and then you can see the Frames (now called Messages) which will show you error messages etc.

enter image description here

Query EC2 tags from within instance

Using the AWS 'user data' and 'meta data' APIs its possible to write a script which wraps puppet to start a puppet run with a custom cert name.

First start an aws instance with custom user data: 'role:webserver'

#!/bin/bash

# Find the name from the user data passed in on instance creation
USER=$(curl -s "http://169.254.169.254/latest/user-data")
IFS=':' read -ra UDATA <<< "$USER"

# Find the instance ID from the meta data api
ID=$(curl -s "http://169.254.169.254/latest/meta-data/instance-id")
CERTNAME=${UDATA[1]}.$ID.aws

echo "Running Puppet for certname: " $CERTNAME
puppet agent -t --certname=$CERTNAME

This calls puppet with a certname like 'webserver.i-hfg453.aws' you can then create a node manifest called 'webserver' and puppets 'fuzzy node matching' will mean it is used to provision all webservers.

This example assumes you build on a base image with puppet installed etc.

Benefits:

1) You don't have to pass round your credentials

2) You can be as granular as you like with the role configs.

How to install JSTL? The absolute uri: http://java.sun.com/jstl/core cannot be resolved

org.apache.jasper.JasperException: The absolute uri: http://java.sun.com/jstl/core cannot be resolved in either web.xml or the jar files deployed with this application

That URI is for JSTL 1.0, but you're actually using JSTL 1.2 which uses URIs with an additional /jsp path (because JSTL, who invented EL expressions, was since version 1.1 integrated as part of JSP in order to share/reuse the EL logic in plain JSP too).

So, fix the taglib URI accordingly based on JSTL documentation:

<%@ taglib prefix="c" uri="http://java.sun.com/jsp/jstl/core" %>

Further you need to make absolutely sure that you do not throw multiple different versioned JSTL JAR files together into the runtime classpath. This is a pretty common mistake among Tomcat users. The problem with Tomcat is that it does not offer JSTL out the box and thus you have to manually install it. This is not necessary in normal Jakarta EE servers. See also What exactly is Java EE?

In your specific case, your pom.xml basically tells you that you have jstl-1.2.jar and standard-1.1.2.jar together. This is wrong. You're basically mixing JSTL 1.2 API+impl from Oracle with JSTL 1.1 impl from Apache. You should stick to only one JSTL implementation.

Installing JSTL on Tomcat 10+

In case you're already on Tomcat 10 or newer (the first Jakartified version, with jakarta.* package instead of javax.* package), use JSTL 2.0 via this sole dependency:

<dependency>
    <groupId>org.glassfish.web</groupId>
    <artifactId>jakarta.servlet.jsp.jstl</artifactId>
    <version>2.0.0</version>
</dependency>

Non-Maven users can achieve the same by dropping the following two physical files in /WEB-INF/lib folder of the web application project (do absolutely not drop standard*.jar or any loose .tld files in there! remove them if necessary).

Installing JSTL on Tomcat 9-

In case you're not on Tomcat 10 yet, but still on Tomcat 9 or older, use JSTL 1.2 via this sole dependency:

<dependency>
    <groupId>org.glassfish.web</groupId>
    <artifactId>jakarta.servlet.jsp.jstl</artifactId>
    <version>1.2.6</version>
</dependency>

Non-Maven users can achieve the same by dropping the following two physical files in /WEB-INF/lib folder of the web application project (do absolutely not drop standard*.jar or any loose .tld files in there! remove them if necessary).

Installing JSTL on normal JEE server

In case you're actually using a normal Jakarta EE server such as WildFly, Payara, etc instead of a barebones servletcontainer such as Tomcat, Jetty, etc, then you don't need to explicitly install JSTL at all. Normal Jakarta EE servers already provide JSTL out the box. In other words, you don't need to add JSTL to pom.xml nor to drop any JAR/TLD files in webapp. Solely the provided scoped Jakarta EE coordinate is sufficient:

<dependency>
    <groupId>jakarta.platform</groupId>
    <artifactId>jakarta.jakartaee-api</artifactId>
    <version><!-- 9.0.0, 8.0.0, etc depending on your server --></version>
    <scope>provided</scope>
</dependency>

Make sure web.xml version is right

Further you should also make sure that your web.xml is declared conform at least Servlet 2.4 and thus not as Servlet 2.3 or older. Otherwise EL expressions inside JSTL tags would in turn fail to work. Pick the highest version matching your target container and make sure that you don't have a <!DOCTYPE> anywhere in your web.xml. Here's a Servlet 5.0 (Tomcat 10) compatible example:

<?xml version="1.0" encoding="UTF-8"?>
<web-app 
    xmlns="https://jakarta.ee/xml/ns/jakartaee"
    xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
    xsi:schemaLocation="https://jakarta.ee/xml/ns/jakartaee https://jakarta.ee/xml/ns/jakartaee/web-app_5_0.xsd"
    version="5.0">

    <!-- Config here. -->

</web-app>

And here's a Servlet 4.0 (Tomcat 9) compatible example:

<?xml version="1.0" encoding="UTF-8"?>
<web-app
    xmlns="http://xmlns.jcp.org/xml/ns/javaee"
    xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
    xsi:schemaLocation="http://xmlns.jcp.org/xml/ns/javaee http://xmlns.jcp.org/xml/ns/javaee/web-app_4_0.xsd"
    version="4.0">

    <!-- Config here. -->

</web-app>

See also:

show more/Less text with just HTML and JavaScript

I'm not an expert, but I did a lot of looking to implement this for myself. I found something different, but modified it to accomplish this. It's really quite simple:

The function takes two arguments, a div containing only the words "show more" [or whatever] and a div containing the originally hidden text and the words "show less." The function displays the one div and hides the other.

NOTE: If more than one show/hide on page, assign different ids to divs Colors can be changed

<p>Here is text that is originally displayed</p>

<div id="div1">
<p style="color:red;" onclick="showFunction('div2','div1')">show more</p></div>
<div id="div2" style="display:none">

<p>Put expanded text here</p>

<p style="color:red;" onclick="showFunction('div1','div2')">show less</p></div>

<p>more text</p>

Here is the Script:

<script>
function showFunction(diva, divb) {
    var x = document.getElementById(diva);
    var y = document.getElementById(divb);
          x.style.display = 'block';
          y.style.display = 'none';
}
</script>

Java swing application, close one window and open another when button is clicked

You can hide a part of JFrame that contains the swing controls which you want on another JFrame.

When the user clicks on a Jbutton the JFrame width increases and when he clicks on another same kind of Jbutton the JFrame comes to the default size.

  JFrame myFrame = new JFrame("");
  JButton button1 = new JButton("Basic");
  JButton button2 = new JButton("More options");
 // actionPerformed block code for button1 (Default size)  
 myFrame.setSize(400, 400);
//  actionPerformed block code for button2 (Increase width)
 myFrame.setSize(600, 400);

XAMPP - MySQL shutdown unexpectedly

Rename below files from mysql/data ib_logfile0 ib_logfile1 ibdata1

my.cnf innodb_buffer_pool_size to 200M as per your ram innodb_log_buffer_size to 32M

Restart your apache server

hope it helps you

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");

How to exit a function in bash

Use return operator:

function FUNCT {
  if [ blah is false ]; then
    return 1 # or return 0, or even you can omit the argument.
  else
    keep running the function
  fi
}

Python: How would you save a simple settings/config file?

If you want to use something like an INI file to hold settings, consider using configparser which loads key value pairs from a text file, and can easily write back to the file.

INI file has the format:

[Section]
key = value
key with spaces = somevalue

In Python, how do you convert a `datetime` object to seconds?

I tried the standard library's calendar.timegm and it works quite well:

# convert a datetime to milliseconds since Epoch
def datetime_to_utc_milliseconds(aDateTime):
    return int(calendar.timegm(aDateTime.timetuple())*1000)

Ref: https://docs.python.org/2/library/calendar.html#calendar.timegm

Remove padding or margins from Google Charts

It's missing in the docs (I'm using version 43), but you can actually use the right and bottom property of the chart area: 

var options = {
  chartArea:{
    left:10,
    right:10, // !!! works !!!
    bottom:20,  // !!! works !!!
    top:20,
    width:"100%",
    height:"100%"
  }
};

So it's possible to use full responsive width & height and prevent any axis labels or legends from being cropped.

"Could not find acceptable representation" using spring-boot-starter-web

Add below dependency to your pom.xml:

<dependency>
    <groupId>com.fasterxml.jackson.dataformat</groupId>
    <artifactId>jackson-dataformat-xml</artifactId>
    <version>2.10.2</version>
</dependency>

Android, How to limit width of TextView (and add three dots at the end of text)?

code:

TextView your_text_view = (TextView) findViewById(R.id.your_id_textview);
your_text_view.setEllipsize(TextUtils.TruncateAt.END);

xml:

android:maxLines = "5"

e.g.

In Matthew 13, the disciples asked Jesus why He spoke to the crowds in parables. He answered, "It has been given to you to know the mysteries of the kingdom of heaven, but to them it has not been given.

Output: In Matthew 13, the disciples asked Jesus why He spoke to the crowds in parables. He answered, "It has been given to you to know...

Picking a random element from a set

In C#

        Random random = new Random((int)DateTime.Now.Ticks);

        OrderedDictionary od = new OrderedDictionary();

        od.Add("abc", 1);
        od.Add("def", 2);
        od.Add("ghi", 3);
        od.Add("jkl", 4);


        int randomIndex = random.Next(od.Count);

        Console.WriteLine(od[randomIndex]);

        // Can access via index or key value:
        Console.WriteLine(od[1]);
        Console.WriteLine(od["def"]);

How should I cast in VB.NET?

I prefer the following syntax:

Dim number As Integer = 1
Dim str As String = String.TryCast(number)

If str IsNot Nothing Then

Hah you can tell I typically write code in C#. 8)

The reason I prefer TryCast is you do not have to mess with the overhead of casting exceptions. Your cast either succeeds or your variable is initialized to null and you deal with that accordingly.

UTF-8 text is garbled when form is posted as multipart/form-data

In case someone stumbled upon this problem when working on Grails (or pure Spring) web application, here is the post that helped me:

http://forum.spring.io/forum/spring-projects/web/2491-solved-character-encoding-and-multipart-forms

To set default encoding to UTF-8 (instead of the ISO-8859-1) for multipart requests, I added the following code in resources.groovy (Spring DSL):

multipartResolver(ContentLengthAwareCommonsMultipartResolver) {
    defaultEncoding = 'UTF-8'
}

Detect element content changes with jQuery

Not possible, I believe ie has a content changed event but it is certainly not x-browser

Should I say not possible without some nasty interval chugging away in the background!

Absolute vs relative URLs

I'm going to have to disagree with the majority here.

I think the relative URL scheme is "fine" when you want to quickly get something up and running and not think outside the box, particularly if your project is small with few developers (or just yourself).

However, once you start working on big, fatty systems where you switch domains and protocols all the time, I believe that a more elegant approach is in order.

When you compare absolute and relative URLs in essence, Absolute wins. Why? Because it won't ever break. Ever. An absolute URL is exactly what it says it is. The catch is when you have to MAINTAIN your absolute URLs.

The weak approach to absolute URL linking is actually hard coding the entire URL. Not a great idea, and probably the culprit of why people see them as dangerous/evil/annoying to maintain. A better approach is to write yourself an easy to use URL generator. These are easy to write, and can be incredibly powerful- automatically detecting your protocol, easy to config (literally set the url once for the whole app), etc, and it injects your domain all by itself. The nice thing about that: You go on coding using relative URLs, and at run time the application inserts your URLs as full absolutes on the fly. Awesome.

Seeing as how practically all modern sites use some sort of dynamic back-end, it's in the best interest of said site to do it that way. Absolute URLs do more than just make you certain of where they point to- they also can improve SEO performance.

I might add that the argument that absolute URLs is somehow going to change the load time of the page is a myth. If your domain weighs more than a few bytes and you're on a dialup modem in the 1980s, sure. But that's just not the case anymore. https://stackoverflow.com/ is 25 bytes, whereas the "topbar-sprite.png" file that they use for the nav area of the site weighs in at 9+ kb. That means that the additional URL data is .2% of the loaded data in comparison to the sprite file, and that file is not even considered a big performance hit.

That big, unoptimized, full-page background image is much more likely to slow your load times.

An interesting post about why relative URLs shouldn't be used is here: Why relative URLs should be forbidden for web developers

An issue that can arise with relatives, for instance, is that sometimes server mappings (mind you on big, messed up projects) don't line up with file names and the developer may make an assumption about a relative URL that just isn't true. I just saw that today on a project that I'm on and it brought an entire page down.

Or perhaps a developer forgot to switch a pointer and all of a sudden google indexed your entire test environment. Whoops- duplicate content (bad for SEO!).

Absolutes can be dangerous, but when used properly and in a way that can't break your build they are proven to be more reliable. Look at the article above which gives a bunch of reasons why the Wordpress url generator is super awesome.

:)

Android: Getting a file URI from a content URI?

Inspired answers are Jason LaBrun & Darth Raven. Trying already answered approaches led me to below solution which may mostly cover cursor null cases & conversion from content:// to file://

To convert file, read&write the file from gained uri

public static Uri getFilePathFromUri(Uri uri) throws IOException {
    String fileName = getFileName(uri);
    File file = new File(myContext.getExternalCacheDir(), fileName);
    file.createNewFile();
    try (OutputStream outputStream = new FileOutputStream(file);
         InputStream inputStream = myContext.getContentResolver().openInputStream(uri)) {
        FileUtil.copyStream(inputStream, outputStream); //Simply reads input to output stream
        outputStream.flush();
    }
    return Uri.fromFile(file);
}

To get filename use, it will cover cursor null case 

public static String getFileName(Uri uri) {
    String fileName = getFileNameFromCursor(uri);
    if (fileName == null) {
        String fileExtension = getFileExtension(uri);
        fileName = "temp_file" + (fileExtension != null ? "." + fileExtension : "");
    } else if (!fileName.contains(".")) {
        String fileExtension = getFileExtension(uri);
        fileName = fileName + "." + fileExtension;
    }
    return fileName;
}

There is good option to converting from mime type to file extention

 public static String getFileExtension(Uri uri) {
    String fileType = myContext.getContentResolver().getType(uri);
    return MimeTypeMap.getSingleton().getExtensionFromMimeType(fileType);
}

Cursor to obtain name of file

public static String getFileNameFromCursor(Uri uri) {
    Cursor fileCursor = myContext.getContentResolver().query(uri, new String[]{OpenableColumns.DISPLAY_NAME}, null, null, null);
    String fileName = null;
    if (fileCursor != null && fileCursor.moveToFirst()) {
        int cIndex = fileCursor.getColumnIndex(OpenableColumns.DISPLAY_NAME);
        if (cIndex != -1) {
            fileName = fileCursor.getString(cIndex);
        }
    }
    return fileName;
}

How to get the number of characters in a string

I tried to make to do the normalization a bit faster:

    en, _ = glyphSmart(data)

    func glyphSmart(text string) (int, int) {
        gc := 0
        dummy := 0
        for ind, _ := range text {
            gc++
            dummy = ind
        }
        dummy = 0
        return gc, dummy
    }

duplicate 'row.names' are not allowed error

Another possible reason for this error is that you have entire rows duplicated. If that is the case, the problem is solved by removing the duplicate rows.

Is it possible to declare two variables of different types in a for loop?

See "Is there a way to define variables of two types in for loop?" for another way involving nesting multiple for loops. The advantage of the other way over Georg's "struct trick" is that it (1) allows you to have a mixture of static and non-static local variables and (2) it allows you to have non-copyable variables. The downside is that it is far less readable and may be less efficient.

show distinct column values in pyspark dataframe: python

Let's assume we're working with the following representation of data (two columns, k and v, where k contains three entries, two unique:

+---+---+
|  k|  v|
+---+---+
|foo|  1|
|bar|  2|
|foo|  3|
+---+---+

With a Pandas dataframe:

import pandas as pd
p_df = pd.DataFrame([("foo", 1), ("bar", 2), ("foo", 3)], columns=("k", "v"))
p_df['k'].unique()

This returns an ndarray, i.e. array(['foo', 'bar'], dtype=object)

You asked for a "pyspark dataframe alternative for pandas df['col'].unique()". Now, given the following Spark dataframe:

s_df = sqlContext.createDataFrame([("foo", 1), ("bar", 2), ("foo", 3)], ('k', 'v'))

If you want the same result from Spark, i.e. an ndarray, use toPandas():

s_df.toPandas()['k'].unique()

Alternatively, if you don't need an ndarray specifically and just want a list of the unique values of column k:

s_df.select('k').distinct().rdd.map(lambda r: r[0]).collect()

Finally, you can also use a list comprehension as follows:

[i.k for i in s_df.select('k').distinct().collect()]

Open JQuery Datepicker by clicking on an image w/ no input field

Turns out that a simple hidden input field does the job:

<input type="hidden" id="dp" />

And then use the buttonImage attribute for your image, like normal:

    $("#dp").datepicker({
        buttonImage: '../images/icon_star.gif',
        buttonImageOnly: true,
        changeMonth: true,
        changeYear: true,
        showOn: 'both',
     });

Initially I tried a text input field and then set a display:none style on it, but that caused the calendar to emerge from the top of the browser, rather than from where the user clicked. But the hidden field works as desired.

How to iterate through property names of Javascript object?

In JavaScript 1.8.5, Object.getOwnPropertyNames returns an array of all properties found directly upon a given object. 

Object.getOwnPropertyNames ( obj )

and another method Object.keys, which returns an array containing the names of all of the given object's own enumerable properties.

Object.keys( obj )

I used forEach to list values and keys in obj, same as for (var key in obj) ..

Object.keys(obj).forEach(function (key) {
      console.log( key , obj[key] );
});

This all are new features in ECMAScript , the mothods getOwnPropertyNames, keys won't supports old browser's.

How to check user is "logged in"?

The simplest way:

if (Request.IsAuthenticated) ...

Should methods in a Java interface be declared with or without a public access modifier?

I always write what I would use if there was no interface and I was writing a direct implementation, i.e., I would use public.

Add rows to CSV File in powershell

Create a new custom object and add it to the object array that Import-Csv creates.

$fileContent = Import-csv $file -header "Date", "Description"
$newRow = New-Object PsObject -Property @{ Date = 'Text4' ; Description = 'Text5' }
$fileContent += $newRow

How can I check if a Perl array contains a particular value?

If you need to know the amount of every element in array besides existing of that element you may use

my %bad_param_lookup;
@bad_param_lookup{ @bad_params } = ( 1 ) x @bad_params;
%bad_param_lookup = map { $_ => $bad_param_lookup{$_}++} @bad_params;

and then for every $i that is in @bad_params, $bad_param_lookup{$i} contains amount of $i in @bad_params

Python: import module from another directory at the same level in project hierarchy

I faced the same issues. To solve this, I used export PYTHONPATH="$PWD". However, in this case, you will need to modify imports in your Scripts dir depending on the below:

Case 1: If you are in the user_management dir, your scripts should use this style from Modules import LDAPManager to import module.

Case 2: If you are out of the user_management 1 level like main, your scripts should use this style from user_management.Modules import LDAPManager to import modules.

Why does "npm install" rewrite package-lock.json?

You probably have something like:

"typescript":"~2.1.6"

in your package.json which npm updates to the latest minor version, in your case being 2.4.1

Edit: Question from OP

But that doesn't explain why "npm install" would change the lock file. Isn't the lock file meant to create a reproducible build? If so, regardless of the semver value, it should still use the same 2.1.6 version.

Answer:

This is intended to lock down your full dependency tree. Let's say typescript v2.4.1 requires widget ~v1.0.0. When you npm install it grabs widget v1.0.0. Later on your fellow developer (or CI build) does an npm install and gets typescript v2.4.1 but widget has been updated to widget v1.0.1. Now your node module are out of sync. This is what package-lock.json prevents.

Or more generally:

As an example, consider

package A:

{ "name": "A", "version": "0.1.0", "dependencies": { "B": "<0.1.0" } }

package B:

{ "name": "B", "version": "0.0.1", "dependencies": { "C": "<0.1.0" } }

and package C:

{ "name": "C", "version": "0.0.1" }

If these are the only versions of A, B, and C available in the registry, then a normal npm install A will install:

[email protected] -- [email protected] -- [email protected]

However, if [email protected] is published, then a fresh npm install A will install:

[email protected] -- [email protected] -- [email protected] assuming the new version did not modify B's dependencies. Of course, the new version of B could include a new version of C and any number of new dependencies. If such changes are undesirable, the author of A could specify a dependency on [email protected]. However, if A's author and B's author are not the same person, there's no way for A's author to say that he or she does not want to pull in newly published versions of C when B hasn't changed at all.

OP Question 2: So let me see if I understand correctly. What you're saying is that the lock file specifies the versions of the secondary dependencies, but still relies on the fuzzy matching of package.json to determine the top-level dependencies. Is that accurate?

Answer: No. package-lock locks the entire package tree, including the root packages described in package.json. If typescript is locked at 2.4.1 in your package-lock.json, it should remain that way until it is changed. And lets say tomorrow typescript releases version 2.4.2. If I checkout your branch and run npm install, npm will respect the lockfile and install 2.4.1.

More on package-lock.json:

package-lock.json is automatically generated for any operations where npm modifies either the node_modules tree, or package.json. It describes the exact tree that was generated, such that subsequent installs are able to generate identical trees, regardless of intermediate dependency updates.

This file is intended to be committed into source repositories, and serves various purposes:

Describe a single representation of a dependency tree such that teammates, deployments, and continuous integration are guaranteed to install exactly the same dependencies.

Provide a facility for users to "time-travel" to previous states of node_modules without having to commit the directory itself.

To facilitate greater visibility of tree changes through readable source control diffs.

And optimize the installation process by allowing npm to skip repeated metadata resolutions for previously-installed packages.

https://docs.npmjs.com/files/package-lock.json

SQL/mysql - Select distinct/UNIQUE but return all columns?

Try

SELECT table.* FROM table 
WHERE otherField = 'otherValue'
GROUP BY table.fieldWantedToBeDistinct
limit x

Spring Boot Java Config Set Session Timeout
  • Spring Boot version 1.0: server.session.timeout=1200
  • Spring Boot version 2.0: server.servlet.session.timeout=10m
    NOTE: If a duration suffix is not specified, seconds will be used.

PHPMailer character encoding issues

 
$mail -> CharSet = "UTF-8";
$mail = new PHPMailer();

line $mail -> CharSet = "UTF-8"; must be after $mail = new PHPMailer(); and with no spaces!

try this

$mail = new PHPMailer();
$mail->CharSet = "UTF-8";

What does ON [PRIMARY] mean?

It refers to which filegroup the object you are creating resides on. So your Primary filegroup could reside on drive D:\ of your server. you could then create another filegroup called Indexes. This filegroup could reside on drive E:\ of your server.

How to specify names of columns for x and y when joining in dplyr?

This is more a workaround than a real solution. You can create a new object test_data with another column name:

left_join("names<-"(test_data, "name"), kantrowitz, by = "name")

     name gender
1    john      M
2    bill either
3 madison      M
4    abby either
5     zzz   <NA>

How do I enumerate through a JObject?

JObjects can be enumerated via JProperty objects by casting it to a JToken:

foreach (JProperty x in (JToken)obj) { // if 'obj' is a JObject
    string name = x.Name;
    JToken value = x.Value;
}

If you have a nested JObject inside of another JObject, you don't need to cast because the accessor will return a JToken:

foreach (JProperty x in obj["otherObject"]) { // Where 'obj' and 'obj["otherObject"]' are both JObjects
    string name = x.Name;
    JToken value = x.Value;
}

Java Keytool error after importing certificate , "keytool error: java.io.FileNotFoundException & Access Denied"

I had the same problem under Windows and could solve it by running cmd.exe as administrator (right-click in start menu, then "Run as administrator).

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

Disable SELinux

Disable SELinux temporarily

sudo setenforce 0

Restart httpd service

service httpd restart

Disable SELinux persistently (after reboot)

vi /etc/selinux/config

Add line and save

SELINUX=disabled

Best way to parse RSS/Atom feeds with PHP

With 4 lines, I import a rss to an array.

$feed = implode(file('http://yourdomains.com/feed.rss'));
$xml = simplexml_load_string($feed);
$json = json_encode($xml);
$array = json_decode($json,TRUE);

For a more complex solution

$feed = new DOMDocument();
 $feed->load('file.rss');
 $json = array();
 $json['title'] = $feed->getElementsByTagName('channel')->item(0)->getElementsByTagName('title')->item(0)->firstChild->nodeValue;
 $json['description'] = $feed->getElementsByTagName('channel')->item(0)->getElementsByTagName('description')->item(0)->firstChild->nodeValue;
 $json['link'] = $feed->getElementsByTagName('channel')->item(0)->getElementsByTagName('link')->item(0)->firstChild->nodeValue;
 $items = $feed->getElementsByTagName('channel')->item(0)->getElementsByTagName('item');

 $json['item'] = array();
 $i = 0;

 foreach($items as $key => $item) {
 $title = $item->getElementsByTagName('title')->item(0)->firstChild->nodeValue;
 $description = $item->getElementsByTagName('description')->item(0)->firstChild->nodeValue;
 $pubDate = $item->getElementsByTagName('pubDate')->item(0)->firstChild->nodeValue;
 $guid = $item->getElementsByTagName('guid')->item(0)->firstChild->nodeValue;

 $json['item'][$key]['title'] = $title;
 $json['item'][$key]['description'] = $description;
 $json['item'][$key]['pubdate'] = $pubDate;
 $json['item'][$key]['guid'] = $guid; 
 }

echo json_encode($json);

How to know if two arrays have the same values

If your array items are not objects- if they are numbers or strings, for example, you can compare their joined strings to see if they have the same members in any order-

var array1= [10, 6, 19, 16, 14, 15, 2, 9, 5, 3, 4, 13, 8, 7, 1, 12, 18, 11, 20, 17];
var array2= [12, 18, 20, 11, 19, 14, 6, 7, 8, 16, 9, 3, 1, 13, 5, 4, 15, 10, 2, 17];

if(array1.sort().join(',')=== array2.sort().join(',')){
    alert('same members');
}
else alert('not a match');

How to use a servlet filter in Java to change an incoming servlet request url?

A simple JSF Url Prettyfier filter based in the steps of BalusC's answer. The filter forwards all the requests starting with the /ui path (supposing you've got all your xhtml files stored there) to the same path, but adding the xhtml suffix.

public class UrlPrettyfierFilter implements Filter {

    private static final String JSF_VIEW_ROOT_PATH = "/ui";

    private static final String JSF_VIEW_SUFFIX = ".xhtml";

    @Override
    public void destroy() {

    }

    @Override
    public void doFilter(ServletRequest request, ServletResponse response, FilterChain chain)
            throws IOException, ServletException {
        HttpServletRequest httpServletRequest = ((HttpServletRequest) request);
        String requestURI = httpServletRequest.getRequestURI();
        //Only process the paths starting with /ui, so as other requests get unprocessed. 
        //You can register the filter itself for /ui/* only, too
        if (requestURI.startsWith(JSF_VIEW_ROOT_PATH) 
                && !requestURI.contains(JSF_VIEW_SUFFIX)) {
            request.getRequestDispatcher(requestURI.concat(JSF_VIEW_SUFFIX))
                .forward(request,response);
        } else {
            chain.doFilter(httpServletRequest, response);
        }
    }

    @Override
    public void init(FilterConfig arg0) throws ServletException {

    }

}

Add Text on Image using PIL

With Pillow, you can also draw on an image using the ImageDraw module. You can draw lines, points, ellipses, rectangles, arcs, bitmaps, chords, pieslices, polygons, shapes and text.

from PIL import Image, ImageDraw
blank_image = Image.new('RGBA', (400, 300), 'white')
img_draw = ImageDraw.Draw(blank_image)
img_draw.rectangle((70, 50, 270, 200), outline='red', fill='blue')
img_draw.text((70, 250), 'Hello World', fill='green')
blank_image.save('drawn_image.jpg')

we create an Image object with the new() method. This returns an Image object with no loaded image. We then add a rectangle and some text to the image before saving it.

Why is nginx responding to any domain name?

I was unable to resolve my problem with any of the other answers. I resolved the issue by checking to see if the host matched and returning a 403 if it did not. (I had some random website pointing to my web servers content. I'm guessing to hijack search rank)

server {
    listen 443;
    server_name example.com;

    if ($host != "example.com") {
        return 403;
    }

    ...
}

Custom HTTP headers : naming conventions

The question bears re-reading. The actual question asked is not similar to vendor prefixes in CSS properties, where future-proofing and thinking about vendor support and official standards is appropriate. The actual question asked is more akin to choosing URL query parameter names. Nobody should care what they are. But name-spacing the custom ones is a perfectly valid -- and common, and correct -- thing to do.

Rationale:
It is about conventions among developers for custom, application-specific headers -- "data relevant to their account" -- which have nothing to do with vendors, standards bodies, or protocols to be implemented by third parties, except that the developer in question simply needs to avoid header names that may have other intended use by servers, proxies or clients. For this reason, the "X-Gzip/Gzip" and "X-Forwarded-For/Forwarded-For" examples given are moot. The question posed is about conventions in the context of a private API, akin to URL query parameter naming conventions. It's a matter of preference and name-spacing; concerns about "X-ClientDataFoo" being supported by any proxy or vendor without the "X" are clearly misplaced.

There's nothing special or magical about the "X-" prefix, but it helps to make it clear that it is a custom header. In fact, RFC-6648 et al help bolster the case for use of an "X-" prefix, because -- as vendors of HTTP clients and servers abandon the prefix -- your app-specific, private-API, personal-data-passing-mechanism is becoming even better-insulated against name-space collisions with the small number of official reserved header names. That said, my personal preference and recommendation is to go a step further and do e.g. "X-ACME-ClientDataFoo" (if your widget company is "ACME").

IMHO the IETF spec is insufficiently specific to answer the OP's question, because it fails to distinguish between completely different use cases: (A) vendors introducing new globally-applicable features like "Forwarded-For" on the one hand, vs. (B) app developers passing app-specific strings to/from client and server. The spec only concerns itself with the former, (A). The question here is whether there are conventions for (B). There are. They involve grouping the parameters together alphabetically, and separating them from the many standards-relevant headers of type (A). Using the "X-" or "X-ACME-" prefix is convenient and legitimate for (B), and does not conflict with (A). The more vendors stop using "X-" for (A), the more cleanly-distinct the (B) ones will become.

Example:
Google (who carry a bit of weight in the various standards bodies) are -- as of today, 20141102 in this slight edit to my answer -- currently using "X-Mod-Pagespeed" to indicate the version of their Apache module involved in transforming a given response. Is anyone really suggesting that Google should use "Mod-Pagespeed", without the "X-", and/or ask the IETF to bless its use?

Summary:
If you're using custom HTTP Headers (as a sometimes-appropriate alternative to cookies) within your app to pass data to/from your server, and these headers are, explicitly, NOT intended ever to be used outside the context of your application, name-spacing them with an "X-" or "X-FOO-" prefix is a reasonable, and common, convention.

How to assign an action for UIImageView object in Swift

Swift4 Code

Try this some new extension methods:

import UIKit

extension UIView {

    fileprivate struct AssociatedObjectKeys {
        static var tapGestureRecognizer = "MediaViewerAssociatedObjectKey_mediaViewer"
    }

    fileprivate typealias Action = (() -> Void)?


    fileprivate var tapGestureRecognizerAction: Action? {
        set {
            if let newValue = newValue {
                // Computed properties get stored as associated objects
                objc_setAssociatedObject(self, &AssociatedObjectKeys.tapGestureRecognizer, newValue, objc_AssociationPolicy.OBJC_ASSOCIATION_RETAIN)
            }
        }
        get {
            let tapGestureRecognizerActionInstance = objc_getAssociatedObject(self, &AssociatedObjectKeys.tapGestureRecognizer) as? Action
            return tapGestureRecognizerActionInstance
        }
    }


    public func addTapGestureRecognizer(action: (() -> Void)?) {
        self.isUserInteractionEnabled = true
        self.tapGestureRecognizerAction = action
        let tapGestureRecognizer = UITapGestureRecognizer(target: self, action: #selector(handleTapGesture))
        self.addGestureRecognizer(tapGestureRecognizer)
    }


    @objc fileprivate func handleTapGesture(sender: UITapGestureRecognizer) {
        if let action = self.tapGestureRecognizerAction {
            action?()
        } else {
            print("no action")
        }
    }

}

Now whenever we want to add a UITapGestureRecognizer to a UIView or UIView subclass like UIImageView, we can do so without creating associated functions for selectors!

Usage:

 profile_ImageView.addTapGestureRecognizer {
        print("image tapped")
    }

Resolve promises one after another (i.e. in sequence)?

Nicest solution that I was able to figure out was with bluebird promises. You can just do Promise.resolve(files).each(fs.readFileAsync); which guarantees that promises are resolved sequentially in order.

Assign command output to variable in batch file

This post has a method to achieve this

from (zvrba) You can do it by redirecting the output to a file first. For example: 

echo zz > bla.txt
set /p VV=<bla.txt
echo %VV%

codeigniter, result() vs. result_array()

result_array() returns Associative Array type data. Returning pure array is slightly faster than returning an array of objects. result() is recursive in that it returns an std class object where as result_array() just returns a pure array, so result_array() would be choice regarding performance.

No assembly found containing an OwinStartupAttribute Error

you may not have Configuration method in the class you mentioned in

<appSettings>
<add key="owin:AppStartup" value="WebApplication1.App_Start.Startup"/>

Adding Counter in shell script

Here's how you might implement a counter:

counter=0
while true; do
  if /home/hadoop/latest/bin/hadoop fs -ls /apps/hdtech/bds/quality-rt/dt=$DATE_YEST_FORMAT2 then
       echo "Files Present" | mailx -s "File Present"  -r [email protected] [email protected]
       exit 0
  elif [[ "$counter" -gt 20 ]]; then
       echo "Counter: $counter times reached; Exiting loop!"
       exit 1
  else
       counter=$((counter+1))
       echo "Counter: $counter time(s); Sleeping for another half an hour" | mailx -s "Time to Sleep Now"  -r [email protected] [email protected]
       sleep 1800
  fi
done

Some Explanations:

  • counter=$((counter+1)) - this is how you can increment a counter. The $ for counter is optional inside the double parentheses in this case.
  • elif [[ "$counter" -gt 20 ]]; then - this checks whether $counter is not greater than 20. If so, it outputs the appropriate message and breaks out of your while loop.

Create a CSV File for a user in PHP

The easiest way is to use a dedicated CSV class like this:

$csv = new csv();
$csv->load_data(array(
    array('name'=>'John', 'age'=>35),
    array('name'=>'Adrian', 'age'=>23), 
    array('name'=>'William', 'age'=>57) 
));
$csv->send_file('age.csv');

Difference between Static and final?

Think of an object like a Speaker. If Speaker is a class, It will have different variables such as volume, treble, bass, color etc. You define all these fields while defining the Speaker class. For example, you declared the color field with a static modifier, that means you're telling the compiler that there is exactly one copy of this variable in existence, regardless of how many times the class has been instantiated.

Declaring 

static final String color = "Black";

will make sure that whenever this class is instantiated, the value of color field will be "Black" unless it is not changed.

public class Speaker {

static String color = "Black";

}

public class Sample {

public static void main(String args[]) {
    System.out.println(Speaker.color); //will provide output as "Black"
            Speaker.color = "white";
    System.out.println(Speaker.color);  //will provide output as "White"
}}

Note : Now once you change the color of the speaker as final this code wont execute, because final keyword makes sure that the value of the field never changes.

public class Speaker {

static final String color = "Black";

}

public class Sample {

public static void main(String args[]) {
    System.out.println(Speaker.color); //should provide output as "Black"
            Speaker.color = "white"; //Error because the value of color is fixed.  
    System.out.println(Speaker.color); //Code won't execute.
}}

You may copy/paste this code directly into your emulator and try.

Unable to login to SQL Server + SQL Server Authentication + Error: 18456

I had this same problem, however mine was because I hadn't set the Server authentication to "SQL Server and Windows Authentication mode" (which you had) I just wanted to mention it here in case someone missed it in your question.

You can access this by

  • Right click on instance (IE SQLServer2008)
  • Select "Properties"
  • Select "Security" option
  • Change "Server authentication" to "SQL Server and Windows Authentication mode"
  • Restart the SQLServer service
    • Right click on instance
    • Click "Restart"

Get a list of dates between two dates

I would use this stored procedure to generate the intervals you need into the temp table named time_intervals, then JOIN and aggregate your data table with the temp time_intervals table.

The procedure can generate intervals of all the different types you see specified in it: 

call make_intervals('2009-01-01 00:00:00','2009-01-10 00:00:00',1,'DAY')
.
select * from time_intervals  
.
interval_start      interval_end        
------------------- ------------------- 
2009-01-01 00:00:00 2009-01-01 23:59:59 
2009-01-02 00:00:00 2009-01-02 23:59:59 
2009-01-03 00:00:00 2009-01-03 23:59:59 
2009-01-04 00:00:00 2009-01-04 23:59:59 
2009-01-05 00:00:00 2009-01-05 23:59:59 
2009-01-06 00:00:00 2009-01-06 23:59:59 
2009-01-07 00:00:00 2009-01-07 23:59:59 
2009-01-08 00:00:00 2009-01-08 23:59:59 
2009-01-09 00:00:00 2009-01-09 23:59:59 
.
call make_intervals('2009-01-01 00:00:00','2009-01-01 02:00:00',10,'MINUTE')
. 
select * from time_intervals
.  
interval_start      interval_end        
------------------- ------------------- 
2009-01-01 00:00:00 2009-01-01 00:09:59 
2009-01-01 00:10:00 2009-01-01 00:19:59 
2009-01-01 00:20:00 2009-01-01 00:29:59 
2009-01-01 00:30:00 2009-01-01 00:39:59 
2009-01-01 00:40:00 2009-01-01 00:49:59 
2009-01-01 00:50:00 2009-01-01 00:59:59 
2009-01-01 01:00:00 2009-01-01 01:09:59 
2009-01-01 01:10:00 2009-01-01 01:19:59 
2009-01-01 01:20:00 2009-01-01 01:29:59 
2009-01-01 01:30:00 2009-01-01 01:39:59 
2009-01-01 01:40:00 2009-01-01 01:49:59 
2009-01-01 01:50:00 2009-01-01 01:59:59 
.
I specified an interval_start and interval_end so you can aggregate the 
data timestamps with a "between interval_start and interval_end" type of JOIN.
.
Code for the proc:
.
-- drop procedure make_intervals
.
CREATE PROCEDURE make_intervals(startdate timestamp, enddate timestamp, intval integer, unitval varchar(10))
BEGIN
-- *************************************************************************
-- Procedure: make_intervals()
--    Author: Ron Savage
--      Date: 02/03/2009
--
-- Description:
-- This procedure creates a temporary table named time_intervals with the
-- interval_start and interval_end fields specifed from the startdate and
-- enddate arguments, at intervals of intval (unitval) size.
-- *************************************************************************
   declare thisDate timestamp;
   declare nextDate timestamp;
   set thisDate = startdate;

   -- *************************************************************************
   -- Drop / create the temp table
   -- *************************************************************************
   drop temporary table if exists time_intervals;
   create temporary table if not exists time_intervals
      (
      interval_start timestamp,
      interval_end timestamp
      );

   -- *************************************************************************
   -- Loop through the startdate adding each intval interval until enddate
   -- *************************************************************************
   repeat
      select
         case unitval
            when 'MICROSECOND' then timestampadd(MICROSECOND, intval, thisDate)
            when 'SECOND'      then timestampadd(SECOND, intval, thisDate)
            when 'MINUTE'      then timestampadd(MINUTE, intval, thisDate)
            when 'HOUR'        then timestampadd(HOUR, intval, thisDate)
            when 'DAY'         then timestampadd(DAY, intval, thisDate)
            when 'WEEK'        then timestampadd(WEEK, intval, thisDate)
            when 'MONTH'       then timestampadd(MONTH, intval, thisDate)
            when 'QUARTER'     then timestampadd(QUARTER, intval, thisDate)
            when 'YEAR'        then timestampadd(YEAR, intval, thisDate)
         end into nextDate;

      insert into time_intervals select thisDate, timestampadd(MICROSECOND, -1, nextDate);
      set thisDate = nextDate;
   until thisDate >= enddate
   end repeat;

 END;

Similar example data scenario at the bottom of this post, where I built a similar function for SQL Server.

Label word wrapping

Refer to Automatically Wrap Text in Label. It describes how to create your own growing label.

Here is the full source taken from the above reference:

using System;
using System.Text;
using System.Drawing;
using System.Windows.Forms;

public class GrowLabel : Label {
  private bool mGrowing;
  public GrowLabel() {
    this.AutoSize = false;
  }
  private void resizeLabel() {
    if (mGrowing) return;
    try {
      mGrowing = true;
      Size sz = new Size(this.Width, Int32.MaxValue);
      sz = TextRenderer.MeasureText(this.Text, this.Font, sz, TextFormatFlags.WordBreak);
      this.Height = sz.Height;
    }
    finally {
      mGrowing = false;
    }
  }
  protected override void OnTextChanged(EventArgs e) {
    base.OnTextChanged(e);
    resizeLabel();
  }
  protected override void OnFontChanged(EventArgs e) {
    base.OnFontChanged(e);
    resizeLabel();
  }
  protected override void OnSizeChanged(EventArgs e) {
    base.OnSizeChanged(e);
    resizeLabel();
  }
}

REST - HTTP Post Multipart with JSON

If I understand you correctly, you want to compose a multipart request manually from an HTTP/REST console. The multipart format is simple; a brief introduction can be found in the HTML 4.01 spec. You need to come up with a boundary, which is a string not found in the content, let’s say HereGoes. You set request header Content-Type: multipart/form-data; boundary=HereGoes. Then this should be a valid request body:

--HereGoes
Content-Disposition: form-data; name="myJsonString"
Content-Type: application/json

{"foo": "bar"}
--HereGoes
Content-Disposition: form-data; name="photo"
Content-Type: image/jpeg
Content-Transfer-Encoding: base64

<...JPEG content in base64...>
--HereGoes--

C# Version Of SQL LIKE

Have your tried

"This is a string".Contains("string");

Running Selenium WebDriver python bindings in chrome

For Windows' IDE:

If your path doesn't work, you can try to add the chromedriver.exe to your project, like in this project structure.

chromedriver.exe

Then you should load the chromedriver.exe in your main file. As for me, I loaded the driver.exe in driver.py.

def get_chrome_driver():
return webdriver.Chrome("..\\content\\engine\\chromedriver.exe",
                            chrome_options='--no-startup-window')

.. means driver.py's upper directory

. means the directory where the driver.py is located

Hope this will be helpful.

How can I convert a series of images to a PDF from the command line on linux?

Using imagemagick, you can try:

convert page.png page.pdf

Or for multiple images:

convert page*.png mydoc.pdf

Bind event to right mouse click

Just use the event-handler. Something like this should work:

$('.js-my-element').bind('contextmenu', function(e) {
     e.preventDefault();
     alert('The eventhandler will make sure, that the contextmenu dosn&#39;t appear.');
});

How to replace innerHTML of a div using jQuery?

Here is your answer:

//This is the setter of the innerHTML property in jQuery
$('#regTitle').html('Hello World');

//This is the getter of the innerHTML property in jQuery
var helloWorld = $('#regTitle').html();

Save the console.log in Chrome to a file

On Linux (at least) you can set CHROME_LOG_FILE in the environment to have chrome write a log of the Console activity to the named file each time it runs. The log is overwritten every time chrome starts. This way, if you have an automated session that runs chrome, you don't have a to change the way chrome is started, and the log is there after the session ends.

export CHROME_LOG_FILE=chrome.log

What's the default password of mariadb on fedora?

I had the same problem. It's true the password is empty, but even so the error message is shown. The solution is just using "sudo" so

$ sudo mysql

will open the mysql tool

For securing the database, you should use sudo again.

$ sudo mysql_secure_installation

Multiple cases in switch statement

gcc implements an extension to the C language to support sequential ranges:

switch (value)
{
   case 1...3:
      //Do Something
      break;
   case 4...6:
      //Do Something
      break;
   default:
      //Do the Default
      break;
}

Edit: Just noticed the C# tag on the question, so presumably a gcc answer doesn't help.

Read whole ASCII file into C++ std::string

Try one of these two methods:

string get_file_string(){
    std::ifstream ifs("path_to_file");
    return string((std::istreambuf_iterator<char>(ifs)),
                  (std::istreambuf_iterator<char>()));
}

string get_file_string2(){
    ifstream inFile;
    inFile.open("path_to_file");//open the input file

    stringstream strStream;
    strStream << inFile.rdbuf();//read the file
    return strStream.str();//str holds the content of the file
}

CSS table-cell equal width

Here is a working fiddle with indeterminate number of cells: http://jsfiddle.net/r9yrM/1/

You can fix a width to each parent div (the table), otherwise it'll be 100% as usual.

The trick is to use table-layout: fixed; and some width on each cell to trigger it, here 2%. That will trigger the other table algorightm, the one where browsers try very hard to respect the dimensions indicated.
Please test with Chrome (and IE8- if needed). It's OK with a recent Safari but I can't remember the compatibility of this trick with them.

CSS (relevant instructions):

div {
    display: table;
    width: 250px;
    table-layout: fixed;
}

div > div {
    display: table-cell;
    width: 2%; /* or 100% according to OP comment. See edit about Safari 6 below */
}

EDIT (2013): Beware of Safari 6 on OS X, it has table-layout: fixed; wrong (or maybe just different, very different from other browsers. I didn't proof-read CSS2.1 REC table layout ;) ). Be prepared to different results.

Add new item in existing array in c#.net

You can expand on the answer provided by @Stephen Chung by using his LINQ based logic to create an extension method using a generic type.

public static class CollectionHelper
{
    public static IEnumerable<T> Add<T>(this IEnumerable<T> sequence, T item)
    {
        return (sequence ?? Enumerable.Empty<T>()).Concat(new[] { item });
    }

    public static T[] AddRangeToArray<T>(this T[] sequence, T[] items)
    {
        return (sequence ?? Enumerable.Empty<T>()).Concat(items).ToArray();
    }

    public static T[] AddToArray<T>(this T[] sequence, T item)
    {
        return Add(sequence, item).ToArray();
    }

}

You can then call it directly on the array like this.

    public void AddToArray(string[] options)
    {
        // Add one item
        options = options.AddToArray("New Item");

        // Add a 
        options = options.AddRangeToArray(new string[] { "one", "two", "three" });

        // Do stuff...
    }

Admittedly, the AddRangeToArray() method seems a bit overkill since you have the same functionality with Concat() but this way the end code can "work" with the array directly as opposed to this:

options = options.Concat(new string[] { "one", "two", "three" }).ToArray();

Reading a UTF8 CSV file with Python

Using codecs.open as Alex Martelli suggested proved to be useful to me.

import codecs

delimiter = ';'
reader = codecs.open("your_filename.csv", 'r', encoding='utf-8')
for line in reader:
    row = line.split(delimiter)
    # do something with your row ...

How to set up devices for VS Code for a Flutter emulator

The following steps were done:

  1. installed genymotion
  2. configured a device and ran it
  3. in the vscode lower right corner the device shows

Using "margin: 0 auto;" in Internet Explorer 8

shouldn't the button be 100% width if it's "display: block"

No. That just means it's the only thing in the space vertically (assuming you aren't using another trick to force something else there as well). It doesn't mean it has to fill up the width of that space.

I think your problem in this instance is that the input is not natively a block element. Try nesting it inside another div and set the margin on that. But I don't have an IE8 browser to test this with at the moment, so it's just a guess.

Django - Static file not found

In your cmd type command python manage.py findstatic --verbosity 2 static It will give the directory in which Django is looking for static files.If you have created a virtual environment then there will be a static folder inside this virtual_environment_name folder. VIRTUAL_ENVIRONMENT_NAME\Lib\site-packages\django\contrib\admin\static. On running the above 'findstatic' command if Django shows you this path then just paste all your static files in this static directory. In your html file use JINJA syntax for href and check for other inline css. If still there is an image src or url after giving JINJA syntax then prepend it with '/static'. This worked for me.

How to convert .crt to .pem

You can do this conversion with the OpenSSL library

http://www.openssl.org/

Windows binaries can be found here:

http://www.slproweb.com/products/Win32OpenSSL.html

Once you have the library installed, the command you need to issue is:

openssl x509 -in mycert.crt -out mycert.pem -outform PEM

Export multiple classes in ES6 modules

Try this in your code:

import Foo from './Foo';
import Bar from './Bar';

// without default
export {
  Foo,
  Bar,
}

Btw, you can also do it this way:

// bundle.js
export { default as Foo } from './Foo'
export { default as Bar } from './Bar'
export { default } from './Baz'

// and import somewhere..
import Baz, { Foo, Bar } from './bundle'

Using export 

export const MyFunction = () => {}
export const MyFunction2 = () => {}

const Var = 1;
const Var2 = 2;

export {
   Var,
   Var2,
}


// Then import it this way
import {
  MyFunction,
  MyFunction2,
  Var,
  Var2,
} from './foo-bar-baz';

The difference with export default is that you can export something, and apply the name where you import it:

// export default
export default class UserClass {
  constructor() {}
};

// import it
import User from './user'

HTTP Status 500 - org.apache.jasper.JasperException: java.lang.NullPointerException

NullPointerException with JSP can also happen if:

A getter returns a non-public inner class.

This code will fail if you remove Getters's access modifier or make it private or protected.

JAVA:

package com.myPackage;
public class MyClass{ 
    //: Must be public or you will get:
    //: org.apache.jasper.JasperException: 
    //: java.lang.NullPointerException
    public class Getters{
        public String 
        myProperty(){ return(my_property); }
    };;

    //: JSP EL can only access functions:
    private Getters _get;
    public  Getters  get(){ return _get; }

    private String 
    my_property;

    public MyClass(String my_property){
        super();
        this.my_property    = my_property;
        _get = new Getters();
    };;
};;

JSP

<%@ taglib uri   ="http://java.sun.com/jsp/jstl/core" prefix="c" %>
<%@ page import="com.myPackage.MyClass" %>
<%
    MyClass inst = new MyClass("[PROP_VALUE]");
    pageContext.setAttribute("my_inst", inst ); 
%><html lang="en"><body>
    ${ my_inst.get().myProperty() }
</body></html>

How can I replace every occurrence of a String in a file with PowerShell?

Here's a fairly simple one that supports multiline regular expressions, multiple files (using the pipeline), specifying output encoding, etc. Not recommended for very large files due to the ReadAllText method.

# Update-FileText.ps1

#requires -version 2

<#
.SYNOPSIS
Updates text in files using a regular expression.

.DESCRIPTION
Updates text in files using a regular expression.

.PARAMETER Pattern
Specifies the regular expression pattern.

.PARAMETER Replacement
Specifies the regular expression replacement pattern.

.PARAMETER Path
Specifies the path to one or more files. Wildcards are not supported. Each file is read entirely into memory to support multi-line searching and replacing, so performance may be slow for large files.

.PARAMETER CaseSensitive
Specifies case-sensitive matching. The default is to ignore case.

.PARAMETER SimpleMatch
Specifies a simple match rather than a regular expression match (i.e., the Pattern parameter specifies a simple string rather than a regular expression).

.PARAMETER Multiline
Changes the meaning of ^ and $ so they match at the beginning and end, respectively, of any line, and not just the beginning and end of the entire file. The default is that ^ and $, respectively, match the beginning and end of the entire file.

.PARAMETER UnixText
Causes $ to match only linefeed (\n) characters. By default, $ matches carriage return+linefeed (\r\n). (Windows-based text files usually use \r\n as line terminators, while Unix-based text files usually use only \n.)

.PARAMETER Overwrite
Overwrites a file by creating a temporary file containing all replacements and then replacing the original file with the temporary file. The default is to output but not overwrite.

.PARAMETER Force
Allows overwriting of read-only files. Note that this parameter cannot override security restrictions.

.PARAMETER Encoding
Specifies the encoding for the file when -Overwrite is used. Possible values for this parameter are ASCII, BigEndianUnicode, Unicode, UTF32, UTF7, and UTF8. The default value is ASCII.

.INPUTS
System.IO.FileInfo.

.OUTPUTS
System.String (single-line file) or System.String[] (file with more than one line) without the -Overwrite parameter, or nothing with the -Overwrite parameter.

.LINK
about_Regular_Expressions

.EXAMPLE
C:\> Update-FileText.ps1 '(Ferb) and (Phineas)' '$2 and $1' Story.txt

This command replaces the text 'Ferb and Phineas' with the text 'Phineas and Ferb' in the file Story.txt and outputs the content. Note that the pattern and replacement strings are enclosed in single quotes to prevent variable expansion.

.EXAMPLE
C:\> Update-FileText.ps1 'Perry' 'Agent P' Story2.txt -Overwrite

This command replaces the text 'Perry' with the text 'Agent P' in the file Story2.txt.
#>

[CmdletBinding(SupportsShouldProcess = $true,ConfirmImpact = "High")]
param(
  [Parameter(Mandatory = $true,Position = 0,ValueFromPipeline = $true)]
  [String[]] $Path,

  [Parameter(Mandatory = $true,Position = 1)]
  [String] $Pattern,

  [Parameter(Mandatory = $true,Position = 2)]
  [AllowEmptyString()]
  [String] $Replacement,

  [Switch] $CaseSensitive,

  [Switch] $SimpleMatch,

  [Switch] $Multiline,

  [Switch] $UnixText,

  [Switch] $Overwrite,

  [Switch] $Force,

  [ValidateSet("ASCII","BigEndianUnicode","Unicode","UTF32","UTF7","UTF8")]
  [String] $Encoding = "ASCII"
)

begin {
  function Get-TempName {
    param(
      $path
    )
    do {
      $tempName = Join-Path $path ([IO.Path]::GetRandomFilename())
    }
    while ( Test-Path $tempName )
    $tempName
  }

  if ( $SimpleMatch ) {
      $Pattern = [Regex]::Escape($Pattern)
  }
  else {
    if ( -not $UnixText ) {
      $Pattern = $Pattern -replace '(?<!\\)\$','\r$'
    }
  }

  function New-Regex {
    $regexOpts = [Text.RegularExpressions.RegexOptions]::None
    if ( -not $CaseSensitive ) {
      $regexOpts = $regexOpts -bor [Text.RegularExpressions.RegexOptions]::IgnoreCase
    }
    if ( $Multiline ) {
      $regexOpts = $regexOpts -bor [Text.RegularExpressions.RegexOptions]::Multiline
    }
    New-Object Text.RegularExpressions.Regex $Pattern,$regexOpts
  }

  $Regex = New-Regex

  function Update-FileText {
    param(
      $path
    )
    $pathInfo = Resolve-Path -LiteralPath $path
    if ( $pathInfo ) {
      if ( (Get-Item $pathInfo).GetType().FullName -eq "System.IO.FileInfo" ) {
        $fullName = $pathInfo.Path
        Write-Verbose "Reading '$fullName'"
        $text = [IO.File]::ReadAllText($fullName)
        Write-Verbose "Finished reading '$fullName'"
        if ( -not $Overwrite ) {
          $regex.Replace($text,$Replacement)
        }
        else {
          $tempName = Get-TempName (Split-Path $fullName -Parent)
          Set-Content $tempName $null -Confirm:$false
          if ( $? ) {
            Write-Verbose "Created file '$tempName'"
            try {
              Write-Verbose "Started writing '$tempName'"
              [IO.File]::WriteAllText("$tempName",$Regex.Replace($text,$Replacement),[Text.Encoding]::$Encoding)
              Write-Verbose "Finished writing '$tempName'"
              Write-Verbose "Started copying '$tempName' to '$fullName'"
              Copy-Item $tempName $fullName -Force:$Force -ErrorAction Continue
              if ( $? ) {
                Write-Verbose "Finished copying '$tempName' to '$fullName'"
              }
              Remove-Item $tempName
              if ( $? ) {
                Write-Verbose "Removed file '$tempName'"
              }
            }
            catch [Management.Automation.MethodInvocationException] {
              Write-Error $Error[0]
            }
          }
        }
      }
      else {
        Write-Error "The item '$path' must be a file in the file system." -Category InvalidType
      }
    }
  }
}

process {
  foreach ( $PathItem in $Path ) {
    if ( $Overwrite ) {
      if ( $PSCmdlet.ShouldProcess("'$PathItem'","Overwrite file") ) {
        Update-FileText $PathItem
      }
    }
    else {
      Update-FileText $PathItem
    }
  }
}

Also available as a gist on Github.

Getting full JS autocompletion under Sublime Text

As of today (November 2019), Microsoft's TypeScript plugin does what the OP required: https://packagecontrol.io/packages/TypeScript.

How can I keep a container running on Kubernetes?

A container exits when its main process exits. Doing something like:

docker run -itd debian

to hold the container open is frankly a hack that should only be used for quick tests and examples. If you just want a container for testing for a few minutes, I would do:

docker run -d debian sleep 300

Which has the advantage that the container will automatically exit if you forget about it. Alternatively, you could put something like this in a while loop to keep it running forever, or just run an application such as top. All of these should be easy to do in Kubernetes.

The real question is why would you want to do this? Your container should be providing a service, whose process will keep the container running in the background.

CentOS 64 bit bad ELF interpreter

In general, when you get an error like this, just do

yum provides ld-linux.so.2

then you'll see something like:

glibc-2.20-5.fc21.i686 : The GNU libc libraries
Repo        : fedora
Matched from:
Provides    : ld-linux.so.2

and then you just run the following like BRPocock wrote (in case you were wondering what the logic was...):

yum install glibc.i686

Android getResources().getDrawable() deprecated API 22

getDrawable(int drawable) is deprecated in API level 22. For reference see this link.

Now to resolve this problem we have to pass a new constructer along with id like as :-

getDrawable(int id, Resources.Theme theme)

For Solutions Do like this:-

In Java:-

ContextCompat.getDrawable(getActivity(), R.drawable.name);

or

 imgProfile.setImageDrawable(getResources().getDrawable(R.drawable.img_prof, getApplicationContext().getTheme()));

In Kotlin :-

rel_week.background=ContextCompat.getDrawable(this.requireContext(), R.color.colorWhite)

or

 rel_day.background=resources.getDrawable(R.drawable.ic_home, context?.theme)

Hope this will help you.Thanks.

Writing a dictionary to a csv file with one line for every 'key: value'

I've personally always found the csv module kind of annoying. I expect someone else will show you how to do this slickly with it, but my quick and dirty solution is:

with open('dict.csv', 'w') as f:  # This creates the file object for the context 
                                  # below it and closes the file automatically
    l = []
    for k, v in mydict.iteritems(): # Iterate over items returning key, value tuples
        l.append('%s: %s' % (str(k), str(v))) # Build a nice list of strings
    f.write(', '.join(l))                     # Join that list of strings and write out

However, if you want to read it back in, you'll need to do some irritating parsing, especially if it's all on one line. Here's an example using your proposed file format.

with open('dict.csv', 'r') as f: # Again temporary file for reading
    d = {}
    l = f.read().split(',')      # Split using commas
    for i in l:
        values = i.split(': ')   # Split using ': '
        d[values[0]] = values[1] # Any type conversion will need to happen here

MySQL 8.0 - Client does not support authentication protocol requested by server; consider upgrading MySQL client

In MySQL 8.0, caching_sha2_password is the default authentication plugin rather than mysql_native_password. ...

Most of the answers in this question result in a downgrade to the authentication mechanism from caching_sha2_password to mysql_native_password. From a security perspective, this is quite disappointing.

This document extensively discusses caching_sha2_password and of course why it should NOT be a first choice to downgrade the authentication method.

With that, I believe Aidin's answer should be the accepted answer. Instead of downgrading the authentication method, use a connector which matches the server's version instead.

Testing Private method using mockito

I was able to test a private method inside using mockito using reflection. Here is the example, tried to name it such that it makes sense

//Service containing the mock method is injected with mockObjects

@InjectMocks
private ServiceContainingPrivateMethod serviceContainingPrivateMethod;

//Using reflection to change accessibility of the private method

Class<?>[] params = new Class<?>[]{PrivateMethodParameterOne.class, PrivateMethodParameterTwo.class};
    Method m = serviceContainingPrivateMethod .getClass().getDeclaredMethod("privateMethod", params);
    //making private method accessible
    m.setAccessible(true); 
    assertNotNull(m.invoke(serviceContainingPrivateMethod, privateMethodParameterOne, privateMethodParameterTwo).equals(null));

PHP Call to undefined function

Presently I am working on web services where my function is defined and it was throwing an error undefined function.I just added this in autoload.php in codeigniter

$autoload['helper'] = array('common','security','url');

common is the name of my controller.

git diff between two different files

Specify the paths explicitly:

git diff HEAD:full/path/to/foo full/path/to/bar

Check out the --find-renames option in the git-diff docs.

Credit: twaggs.

How do I create a Bash alias?

create a bash_profile at your user root - ex 

/user/username/.bash_profile

open file

vim ~/.bash_profile

add alias as ex. (save and exit)

alias mydir="cd ~/Documents/dirname/anotherdir"

in new terminal just type mydir - it should open 

/user/username/Documents/dirname/anotherdir

jQuery show/hide not working

Just add the document ready function, this way it waits until the DOM has been loaded, also by using the :visible pseudo you can write a simple show and hide function.

Sample

 $(document).ready(function(){

    $( '.expand' ).click(function() {
         if($( '.img_display_content' ).is(":visible")){
              $( '.img_display_content' ).hide();
         } else{
              $( '.img_display_content' ).show();
         }

    });
});

Change Row background color based on cell value DataTable

The equivalent syntax since DataTables 1.10+ is rowCallback

"rowCallback": function( row, data, index ) {
    if ( data[2] == "5" )
    {
        $('td', row).css('background-color', 'Red');
    }
    else if ( data[2] == "4" )
    {
        $('td', row).css('background-color', 'Orange');
    }
}

One of the previous answers mentions createdRow. That may give similar results under some conditions, but it is not the same. For example, if you use draw() after updating a row's data, createdRow will not run. It only runs once. rowCallback will run again.

Load text file as strings using numpy.loadtxt()

Use genfromtxt instead. It's a much more general method than loadtxt:

import numpy as np
print np.genfromtxt('col.txt',dtype='str')

Using the file col.txt:

foo bar
cat dog
man wine

This gives:

[['foo' 'bar']
 ['cat' 'dog']
 ['man' 'wine']]

If you expect that each row has the same number of columns, read the first row and set the attribute filling_values to fix any missing rows.

UICollectionView Self Sizing Cells with Auto Layout

If you implement UICollectionViewDelegateFlowLayout method:

- (CGSize)collectionView:(UICollectionView*)collectionView layout:(UICollectionViewLayout*)collectionViewLayout sizeForItemAtIndexPath:(NSIndexPath*)indexPath

When you call collectionview performBatchUpdates:completion:, the size height will use sizeForItemAtIndexPath instead of preferredLayoutAttributesFittingAttributes.

The rendering process of performBatchUpdates:completion will go through the method preferredLayoutAttributesFittingAttributes but it ignores your changes.

How to toggle font awesome icon on click?

Generally and simply it works like this:

_x000D_
_x000D_ 
<script>_x000D_
            $(document).ready(function () {_x000D_
                $('i').click(function () {_x000D_
                    $(this).toggleClass('fa-plus-square fa-minus-square');_x000D_
                });_x000D_
            });_x000D_
</script>
_x000D_
_x000D_
_x000D_

Maven:Non-resolvable parent POM and 'parent.relativePath' points at wrong local POM

 
         ` Adding the following to pom.xml will resolve the issue.      <pluginRepositories>
        <pluginRepository>
            <id>central</id>
            <name>Central Repository</name>
            <url>https://repo.maven.apache.org/maven2</url>
            <layout>default</layout>
            <snapshots>
                <enabled>false</enabled>
            </snapshots>
            <releases>
                <updatePolicy>never</updatePolicy>
            </releases>
        </pluginRepository>
   </pluginRepositories>
    
   <repositories>
        <repository>
            <id>central</id>
            <name>Central Repository</name>
            <url>https://repo.maven.apache.org/maven2</url>
            <layout>default</layout>
            <snapshots>
                <enabled>false</enabled>
            </snapshots>
        </repository>
   </repositories>   `

Timer Interval 1000 != 1 second?

Instead of Tick event, use Elapsed event.

timer.Elapsed += new EventHandler(TimerEventProcessor);

and change the signiture of TimerEventProcessor method;

private void TimerEventProcessor(object sender, ElapsedEventArgs e)
{
  label1.Text = _counter.ToString();
  _counter += 1;
}

Error while trying to run project: Unable to start program. Cannot find the file specified

I had similar problem while using Silverlight web project...

I got resolved issue by setting startup page (In silverlight .aspx is the startup page).

In project browser right click your startup page and set it.!

see here my screen shot

How can I pass request headers with jQuery's getJSON() method?

The $.getJSON() method is shorthand that does not let you specify advanced options like that. To do that, you need to use the full $.ajax() method.

Notice in the documentation at http://api.jquery.com/jQuery.getJSON/:

This is a shorthand Ajax function, which is equivalent to:

$.ajax({
  url: url,
  dataType: 'json',
  data: data,
  success: callback
});

So just use $.ajax() and provide all the extra parameters you need.

Find multiple files and rename them in Linux

find -execdir rename

https://stackoverflow.com/a/16541670/895245 works directly only for suffixes, but this will work for arbitrary regex replacements on basenames:

PATH=/usr/bin find . -depth -execdir rename 's/_dbg.txt$/_.txt' '{}' \;

or to affect files only:

PATH=/usr/bin find . -type f -execdir rename 's/_dbg.txt$/_.txt' '{}' \;

-execdir first cds into the directory before executing only on the basename.

Tested on Ubuntu 20.04, find 4.7.0, rename 1.10.

Convenient and safer helper for it

find-rename-regex() (
  set -eu
  find_and_replace="$1"
  PATH="$(echo "$PATH" | sed -E 's/(^|:)[^\/][^:]*//g')" \
    find . -depth -execdir rename "${2:--n}" "s/${find_and_replace}" '{}' \;
)

GitHub upstream.

Sample usage to replace spaces ' ' with hyphens '-'.

Dry run that shows what would be renamed to what without actually doing it:

find-rename-regex ' /-/g'

Do the replace:

find-rename-regex ' /-/g' -v

Command explanation

The awesome -execdir option does a cd into the directory before executing the rename command, unlike -exec.

-depth ensure that the renaming happens first on children, and then on parents, to prevent potential problems with missing parent directories.

-execdir is required because rename does not play well with non-basename input paths, e.g. the following fails:

rename 's/findme/replaceme/g' acc/acc

The PATH hacking is required because -execdir has one very annoying drawback: find is extremely opinionated and refuses to do anything with -execdir if you have any relative paths in your PATH environment variable, e.g. ./node_modules/.bin, failing with:

find: The relative path ‘./node_modules/.bin’ is included in the PATH environment variable, which is insecure in combination with the -execdir action of find. Please remove that entry from $PATH

See also: https://askubuntu.com/questions/621132/why-using-the-execdir-action-is-insecure-for-directory-which-is-in-the-path/1109378#1109378

-execdir is a GNU find extension to POSIX. rename is Perl based and comes from the rename package.

Rename lookahead workaround

If your input paths don't come from find, or if you've had enough of the relative path annoyance, we can use some Perl lookahead to safely rename directories as in:

git ls-files | sort -r | xargs rename 's/findme(?!.*\/)\/?$/replaceme/g' '{}'

I haven't found a convenient analogue for -execdir with xargs: https://superuser.com/questions/893890/xargs-change-working-directory-to-file-path-before-executing/915686

The sort -r is required to ensure that files come after their respective directories, since longer paths come after shorter ones with the same prefix.

Tested in Ubuntu 18.10.

How to open my files in data_folder with pandas using relative path?

Pandas will start looking from where your current python file is located. Therefore you can move from your current directory to where your data is located with '..' For example:

pd.read_csv('../../../data_folder/data.csv')

Will go 3 levels up and then into a data_folder (assuming it's there) Or

pd.read_csv('data_folder/data.csv')

assuming your data_folder is in the same directory as your .py file.

Java Error: illegal start of expression

Remove the public keyword from int[] locations={1,2,3};. An access modifier isn't allowed inside a method, as its accessbility is defined by its method scope.

If your goal is to use this reference in many a method, you might want to move the declaration outside the method.

Why does Eclipse Java Package Explorer show question mark on some classes?

With some version-control plug-ins, it means that the local file has not yet been shared with the version-control repository. (In my install, this includes plug-ins for CVS and git, but not Perforce.)

You can sometimes see a list of these decorations in the plug-in's preferences under Team/X/Label Decorations, where X describes the version-control system.

For example, for CVS, the list looks like this:

enter image description here

These adornments are added to the object icons provided by Eclipse. For example, here's a table of icons for the Java development environment.

How do I read an image file using Python?

The word "read" is vague, but here is an example which reads a jpeg file using the Image class, and prints information about it. 

from PIL import Image
jpgfile = Image.open("picture.jpg")

print(jpgfile.bits, jpgfile.size, jpgfile.format)

How to parse a CSV file in Bash?

From the man page:

-d delim The first character of delim is used to terminate the input line, rather than newline.

You are using -d, which will terminate the input line on the comma. It will not read the rest of the line. That's why $y is empty.

How do I disable and re-enable a button in with javascript?

you can try with

document.getElementById('btn').disabled = !this.checked"

_x000D_
_x000D_ 
<input type="submit" name="btn"  id="btn" value="submit" disabled/>_x000D_
_x000D_
<input type="checkbox"  onchange="document.getElementById('btn').disabled = !this.checked"/>
_x000D_
_x000D_
_x000D_

Can't access object property, even though it shows up in a console log

Check whether you had applied any filters in the console. It happens to me in chrome console.

When should I use "this" in a class?

The this keyword is primarily used in three situations. The first and most common is in setter methods to disambiguate variable references. The second is when there is a need to pass the current class instance as an argument to a method of another object. The third is as a way to call alternate constructors from within a constructor.

Case 1: Using this to disambiguate variable references. In Java setter methods, we commonly pass in an argument with the same name as the private member variable we are attempting to set. We then assign the argument x to this.x. This makes it clear that you are assigning the value of the parameter "name" to the instance variable "name".

public class Foo
{
    private String name;

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

Case 2: Using this as an argument passed to another object.

public class Foo
{
    public String useBarMethod() {
        Bar theBar = new Bar();
        return theBar.barMethod(this);
    }

    public String getName() {
        return "Foo";
    }
}

public class Bar
{
    public void barMethod(Foo obj) {
        obj.getName();
    }
}

Case 3: Using this to call alternate constructors. In the comments, trinithis correctly pointed out another common use of this. When you have multiple constructors for a single class, you can use this(arg0, arg1, ...) to call another constructor of your choosing, provided you do so in the first line of your constructor.

class Foo
{
    public Foo() {
        this("Some default value for bar");

        //optional other lines
    }

    public Foo(String bar) {
        // Do something with bar
    }
}

I have also seen this used to emphasize the fact that an instance variable is being referenced (sans the need for disambiguation), but that is a rare case in my opinion.

MySQL LEFT JOIN Multiple Conditions

Just move the extra condition into the JOIN ON criteria, this way the existence of b is not required to return a result

SELECT a.* FROM a 
    LEFT JOIN b ON a.group_id=b.group_id AND b.user_id!=$_SESSION{['user_id']} 
    WHERE a.keyword LIKE '%".$keyword."%' 
    GROUP BY group_id

Adding/removing items from a JavaScript object with jQuery

That's not JSON at all, it's just Javascript objects. JSON is a text representation of data, that uses a subset of the Javascript syntax.

The reason that you can't find any information about manipulating JSON using jQuery is because jQuery has nothing that can do that, and it's generally not done at all. You manipulate the data in the form of Javascript objects, and then turn it into a JSON string if that is what you need. (jQuery does have methods for the conversion, though.)

What you have is simply an object that contains an array, so you can use all the knowledge that you already have. Just use data.items to access the array.

For example, to add another item to the array using dynamic values:

// The values to put in the item
var id = 7;
var name = "The usual suspects";
var type = "crime";
// Create the item using the values
var item = { id: id, name: name, type: type };
// Add the item to the array
data.items.push(item);

Most efficient way to see if an ArrayList contains an object in Java

Maybe a List isn't what you need.

Maybe a TreeSet would be a better container. You get O(log N) insertion and retrieval, and ordered iteration (but won't allow duplicates).

LinkedHashMap might be even better for your use case, check that out too.

What does "@" mean in Windows batch scripts

It means "don't echo the command to standard output".

Rather strangely, 

echo off

will send echo off to the output! So, 

@echo off

sets this automatic echo behaviour off - and stops it for all future commands, too.

Source: http://www.microsoft.com/resources/documentation/windows/xp/all/proddocs/en-us/batch.mspx?mfr=true

database vs. flat files

What about a non-relational (NoSQL) database such as Amazon's SimpleDB, Tokio Cabinet, etc? I've heard that Google, Facebook, LinkedIn are using these to store their huge datasets.

Can you tell us if your data is structured, if your schema is fixed, if you need easy replicability, if access times are important, etc?

How to sum a list of integers with java streams?

This will work, but the i -> i is doing some automatic unboxing which is why it "feels" strange. Either of the following will work and better explain what the compiler is doing under the hood with your original syntax:

integers.values().stream().mapToInt(i -> i.intValue()).sum();
integers.values().stream().mapToInt(Integer::intValue).sum();

check if a string matches an IP address pattern in python?

you should precompile the regexp, if you use it repeatedly

re_ip = re.compile('\d{1,3}\.\d{1,3}\.\d{1,3}\.\d{1,3}$')
# note the terminating $ to really match only the IPs

then use

if re_ip.match(st):
    print '!IP'

but.. is e.g. '111.222.333.444' really the IP?

i'd look at netaddr or ipaddr libraries whether they can be used to match IPs

What is simplest way to read a file into String?

Another alternative approach is:

How do I create a Java string from the contents of a file?

Other option is to use utilities provided open source libraries
http://commons.apache.org/io/api-1.4/index.html?org/apache/commons/io/IOUtils.html

Why java doesn't provide such a common util API ?
a) to keep the APIs generic so that encoding, buffering etc is handled by the programmer.
b) make programmers do some work and write/share opensource util libraries :D ;-)

Equivalent of varchar(max) in MySQL?

The max length of a varchar is

65535

divided by the max byte length of a character in the character set the column is set to (e.g. utf8=3 bytes, ucs2=2, latin1=1).

minus 2 bytes to store the length

minus the length of all the other columns

minus 1 byte for every 8 columns that are nullable. If your column is null/not null this gets stored as one bit in a byte/bytes called the null mask, 1 bit per column that is nullable.

How can foreign key constraints be temporarily disabled using T-SQL?

 
SET NOCOUNT ON

DECLARE @table TABLE(
   RowId INT PRIMARY KEY IDENTITY(1, 1),
   ForeignKeyConstraintName NVARCHAR(200),
   ForeignKeyConstraintTableSchema NVARCHAR(200),
   ForeignKeyConstraintTableName NVARCHAR(200),
   ForeignKeyConstraintColumnName NVARCHAR(200),
   PrimaryKeyConstraintName NVARCHAR(200),
   PrimaryKeyConstraintTableSchema NVARCHAR(200),
   PrimaryKeyConstraintTableName NVARCHAR(200),
   PrimaryKeyConstraintColumnName NVARCHAR(200),
   UpdateRule NVARCHAR(100),
   DeleteRule NVARCHAR(100)   
)

INSERT INTO @table(ForeignKeyConstraintName, ForeignKeyConstraintTableSchema, ForeignKeyConstraintTableName, ForeignKeyConstraintColumnName)
SELECT 
   U.CONSTRAINT_NAME, 
   U.TABLE_SCHEMA, 
   U.TABLE_NAME, 
   U.COLUMN_NAME
FROM 
   INFORMATION_SCHEMA.KEY_COLUMN_USAGE U
      INNER JOIN INFORMATION_SCHEMA.TABLE_CONSTRAINTS C
         ON U.CONSTRAINT_NAME = C.CONSTRAINT_NAME
WHERE
   C.CONSTRAINT_TYPE = 'FOREIGN KEY'

UPDATE @table SET
   T.PrimaryKeyConstraintName = R.UNIQUE_CONSTRAINT_NAME,
   T.UpdateRule = R.UPDATE_RULE,
   T.DeleteRule = R.DELETE_RULE
FROM 
   @table T
      INNER JOIN INFORMATION_SCHEMA.REFERENTIAL_CONSTRAINTS R
         ON T.ForeignKeyConstraintName = R.CONSTRAINT_NAME

UPDATE @table SET
   PrimaryKeyConstraintTableSchema  = TABLE_SCHEMA,
   PrimaryKeyConstraintTableName  = TABLE_NAME
FROM @table T
   INNER JOIN INFORMATION_SCHEMA.TABLE_CONSTRAINTS C
      ON T.PrimaryKeyConstraintName = C.CONSTRAINT_NAME

UPDATE @table SET
   PrimaryKeyConstraintColumnName = COLUMN_NAME
FROM @table T
   INNER JOIN INFORMATION_SCHEMA.KEY_COLUMN_USAGE U
      ON T.PrimaryKeyConstraintName = U.CONSTRAINT_NAME

--SELECT * FROM @table

SELECT '
BEGIN TRANSACTION
BEGIN TRY'

--DROP CONSTRAINT:
SELECT
   '
 ALTER TABLE [' + ForeignKeyConstraintTableSchema + '].[' + ForeignKeyConstraintTableName + '] 
 DROP CONSTRAINT ' + ForeignKeyConstraintName + '
   '
FROM
   @table

SELECT '
END TRY

BEGIN CATCH
   ROLLBACK TRANSACTION
   RAISERROR(''Operation failed.'', 16, 1)
END CATCH

IF(@@TRANCOUNT != 0)
BEGIN
   COMMIT TRANSACTION
   RAISERROR(''Operation completed successfully.'', 10, 1)
END
'

--ADD CONSTRAINT:
SELECT '
BEGIN TRANSACTION
BEGIN TRY'

SELECT
   '
   ALTER TABLE [' + ForeignKeyConstraintTableSchema + '].[' + ForeignKeyConstraintTableName + '] 
   ADD CONSTRAINT ' + ForeignKeyConstraintName + ' FOREIGN KEY(' + ForeignKeyConstraintColumnName + ') REFERENCES [' + PrimaryKeyConstraintTableSchema + '].[' + PrimaryKeyConstraintTableName + '](' + PrimaryKeyConstraintColumnName + ') ON UPDATE ' + UpdateRule + ' ON DELETE ' + DeleteRule + '
   '
FROM
   @table

SELECT '
END TRY

BEGIN CATCH
   ROLLBACK TRANSACTION
   RAISERROR(''Operation failed.'', 16, 1)
END CATCH

IF(@@TRANCOUNT != 0)
BEGIN
   COMMIT TRANSACTION
   RAISERROR(''Operation completed successfully.'', 10, 1)
END'

GO

javascript compare strings without being case sensitive

Another method using a regular expression (this is more correct than Zachary's answer):

var string1 = 'someText',
    string2 = 'SometexT',
    regex = new RegExp('^' + string1 + '$', 'i');

if (regex.test(string2)) {
    return true;
}

RegExp.test() will return true or false.

Also, adding the '^' (signifying the start of the string) to the beginning and '$' (signifying the end of the string) to the end make sure that your regular expression will match only if 'sometext' is the only text in stringToTest. If you're looking for text that contains the regular expression, it's ok to leave those off.

It might just be easier to use the string.toLowerCase() method.

So... regular expressions are powerful, but you should only use them if you understand how they work. Unexpected things can happen when you use something you don't understand.

There are tons of regular expression 'tutorials', but most appear to be trying to push a certain product. Here's what looks like a decent tutorial... granted, it's written for using php, but otherwise, it appears to be a nice beginner's tutorial: http://weblogtoolscollection.com/regex/regex.php

This appears to be a good tool to test regular expressions: http://gskinner.com/RegExr/

How do I implement Toastr JS?

Add CDN Files of toastr.css and toastr.js

<link href="https://cdnjs.cloudflare.com/ajax/libs/toastr.js/2.0.1/css/toastr.css" rel="stylesheet"/>
<script src="https://cdnjs.cloudflare.com/ajax/libs/toastr.js/2.0.1/js/toastr.js"></script>

function toasterOptions() {
    toastr.options = {
        "closeButton": false,
        "debug": false,
        "newestOnTop": false,
        "progressBar": true,
        "positionClass": "toast-top-center",
        "preventDuplicates": true,
        "onclick": null,
        "showDuration": "100",
        "hideDuration": "1000",
        "timeOut": "5000",
        "extendedTimeOut": "1000",
        "showEasing": "swing",
        "hideEasing": "linear",
        "showMethod": "show",
        "hideMethod": "hide"
    };
};


toasterOptions();
toastr.error("Error Message from toastr");

How do you copy and paste into Git Bash

In windows I'm not sure about copy but for paste works Ctrl+Insert. In Linux copy: CTRL+SHIFT+C, paste: CTRL+SHIFT+V

MySQL - Rows to Columns

I make that into Group By hostId then it will show only first row with values,
like:

A   B  C
1  10
2      3

Why should a Java class implement comparable?

For example when you want to have a sorted collection or map

How to allow only one radio button to be checked?

Give them the same name, and it will work. By definition Radio buttons will only have one choice, while check boxes can have many.

<input type="radio" name="Radio1" />

Regular cast vs. static_cast vs. dynamic_cast

FYI, I believe Bjarne Stroustrup is quoted as saying that C-style casts are to be avoided and that you should use static_cast or dynamic_cast if at all possible.

Barne Stroustrup's C++ style FAQ

Take that advice for what you will. I'm far from being a C++ guru.

How to create a inset box-shadow only on one side?

Quite a bit late, but a duplicate answer that doesn't require altering the padding or adding extra divs can be found here: Have an issue with box-shadow Inset bottom only. It says, "Use a negative value for the fourth length which defines the spread distance. This is often overlooked, but supported by all major browsers"

From the answerer's fiddle:

box-shadow: inset 0 -10px 10px -10px #000000;

How to escape a JSON string to have it in a URL?

I was looking to do the same thing. problem for me was my url was getting way too long. I found a solution today using Bruno Jouhier's jsUrl.js library.

I haven't tested it very thoroughly yet. However, here is an example showing character lengths of the string output after encoding the same large object using 3 different methods:

  • 2651 characters using jQuery.param
  • 1691 characters using JSON.stringify + encodeURIComponent
  • 821 characters using JSURL.stringify

clearly JSURL has the most optimized format for urlEncoding a js object.

the thread at https://groups.google.com/forum/?fromgroups=#!topic/nodejs/ivdZuGCF86Q shows benchmarks for encoding and parsing.

Note: After testing, it looks like jsurl.js library uses ECMAScript 5 functions such as Object.keys, Array.map, and Array.filter. Therefore, it will only work on modern browsers (no ie 8 and under). However, are polyfills for these functions that would make it compatible with more browsers.

Inverse dictionary lookup in Python

I know this might be considered 'wasteful', but in this scenario I often store the key as an additional column in the value record:

d = {'key1' : ('key1', val, val...), 'key2' : ('key2', val, val...) }

it's a tradeoff and feels wrong, but it's simple and works and of course depends on values being tuples rather than simple values.

How to convert a Map to List in Java?

map.entrySet() gives you a collection of Map.Entry objects containing both key and value. you can then transform this into any collection object you like, such as new ArrayList(map.entrySet());

How can I check the current status of the GPS receiver?

If you do not need an update on the very instant the fix is lost, you can modify the solution of Stephen Daye in that way, that you have a method that checks if the fix is still present.

So you can just check it whenever you need some GPS data and and you don't need that GpsStatus.Listener.

The "global" variables are:

private Location lastKnownLocation;
private long lastKnownLocationTimeMillis = 0;
private boolean isGpsFix = false;

This is the method that is called within "onLocationChanged()" to remember the update time and the current location. Beside that it updates "isGpsFix":

private void handlePositionResults(Location location) {
        if(location == null) return;

        lastKnownLocation = location;
        lastKnownLocationTimeMillis = SystemClock.elapsedRealtime();

        checkGpsFix(); // optional
    }

That method is called whenever I need to know if there is a GPS fix:

private boolean checkGpsFix(){

    if (SystemClock.elapsedRealtime() - lastKnownLocationTimeMillis < 3000) {
        isGpsFix = true;

    } else {
        isGpsFix = false;
        lastKnownLocation = null;
    }
    return isGpsFix;
}

In my implementation I first run checkGpsFix() and if the result is true I use the variable "lastKnownLocation" as my current position.

Does the 'mutable' keyword have any purpose other than allowing the variable to be modified by a const function?

The classic example (as mentioned in other answers) and the only situation I have seen the mutable keyword used in so far, is for caching the result of a complicated Get method, where the cache is implemented as a data member of the class and not as a static variable in the method (for reasons of sharing between several functions or plain cleanliness).

In general, the alternatives to using the mutable keyword are usually a static variable in the method or the const_cast trick.

Another detailed explanation is in here.

How to read attribute value from XmlNode in C#?

To expand Konamiman's solution (including all relevant null checks), this is what I've been doing:

if (node.Attributes != null)
{
   var nameAttribute = node.Attributes["Name"];
   if (nameAttribute != null) 
      return nameAttribute.Value;

   throw new InvalidOperationException("Node 'Name' not found.");
}

sed whole word search and replace

in shell command:

echo "bar embarassment" | sed "s/\bbar\b/no bar/g"

or:

echo "bar embarassment" | sed "s/\<bar\>/no bar/g"

but if you are in vim, you can only use the later:

:% s/\<old\>/new/g

How to get the number of characters in a std::string?

It might be the easiest way to input a string and find its length. 

// Finding length of a string in C++ 
#include<iostream>
#include<string>
using namespace std;

int count(string);

int main()
{
string str;
cout << "Enter a string: ";
getline(cin,str);
cout << "\nString: " << str << endl;
cout << count(str) << endl;

return 0;

}

int count(string s){
if(s == "")
  return 0;
if(s.length() == 1)
  return 1;
else
    return (s.length());

}

What's the difference between Html.Label, Html.LabelFor and Html.LabelForModel

I think that the usage of @Html.LabelForModel() should be explained in more detail.

The LabelForModel Method returns an HTML label element and the property name of the property that is represented by the model.

You could refer to the following code:

Code in model:

using System.ComponentModel;

[DisplayName("MyModel")]
public class MyModel
{
    [DisplayName("A property")]
    public string Test { get; set; }
}

Code in view:

@Html.LabelForModel()
<div class="form-group">

    @Html.LabelFor(model => model.Test, new { @class = "control-label col-md-2" })

    <div class="col-md-10">
        @Html.EditorFor(model => model.Test)
        @Html.ValidationMessageFor(model => model.Test)
    </div>
</div>

The output screenshot:

enter image description here

Reference to answer on the asp.net forum

Example of a strong and weak entity types

A weak entity is the entity which can't be fully identified by its own attributes and takes the foreign key as an attribute (generally it takes the primary key of the entity it is related to) in conjunction.

Examples

The existence of rooms is entirely dependent on the existence of a hotel. So room can be seen as the weak entity of the hotel.
Another example is the
bank account of a particular bank has no existence if the bank doesn't exist anymore.

Regex: ignore case sensitivity

JavaScript

If you want to make it case insensitive just add i at the end of regex:

'Test'.match(/[A-Z]/gi) //Returns ["T", "e", "s", "t"]

Without i

'Test'.match(/[A-Z]/g) //Returns ["T"]

What's the difference between integer class and numeric class in R

There are multiple classes that are grouped together as "numeric" classes, the 2 most common of which are double (for double precision floating point numbers) and integer. R will automatically convert between the numeric classes when needed, so for the most part it does not matter to the casual user whether the number 3 is currently stored as an integer or as a double. Most math is done using double precision, so that is often the default storage.

Sometimes you may want to specifically store a vector as integers if you know that they will never be converted to doubles (used as ID values or indexing) since integers require less storage space. But if they are going to be used in any math that will convert them to double, then it will probably be quickest to just store them as doubles to begin with.

Colorized grep -- viewing the entire file with highlighted matches

I use rcg from "Linux Server Hacks", O'Reilly. It's perfect for what you want and can highlight multiple expressions each with different colours.

#!/usr/bin/perl -w
#
#       regexp coloured glasses - from Linux Server Hacks from O'Reilly
#
#       eg .rcg "fatal" "BOLD . YELLOW . ON_WHITE"  /var/adm/messages
#
use strict;
use Term::ANSIColor qw(:constants);

my %target = ( );

while (my $arg = shift) {
        my $clr = shift;

        if (($arg =~ /^-/) | !$clr) {
                print "Usage: rcg [regex] [color] [regex] [color] ...\n";
                exit(2);
        }

        #
        # Ugly, lazy, pathetic hack here. [Unquote]
        #
        $target{$arg} = eval($clr);

}

my $rst = RESET;

while(<>) {
        foreach my $x (keys(%target)) {
                s/($x)/$target{$x}$1$rst/g;
        }
        print
}

Why does printf not flush after the call unless a newline is in the format string?

No, it's not POSIX behaviour, it's ISO behaviour (well, it is POSIX behaviour but only insofar as they conform to ISO).

Standard output is line buffered if it can be detected to refer to an interactive device, otherwise it's fully buffered. So there are situations where printf won't flush, even if it gets a newline to send out, such as:

myprog >myfile.txt

This makes sense for efficiency since, if you're interacting with a user, they probably want to see every line. If you're sending the output to a file, it's most likely that there's not a user at the other end (though not impossible, they could be tailing the file). Now you could argue that the user wants to see every character but there are two problems with that.

The first is that it's not very efficient. The second is that the original ANSI C mandate was to primarily codify existing behaviour, rather than invent new behaviour, and those design decisions were made long before ANSI started the process. Even ISO nowadays treads very carefully when changing existing rules in the standards.

As to how to deal with that, if you fflush (stdout) after every output call that you want to see immediately, that will solve the problem.

Alternatively, you can use setvbuf before operating on stdout, to set it to unbuffered and you won't have to worry about adding all those fflush lines to your code:

setvbuf (stdout, NULL, _IONBF, BUFSIZ);

Just keep in mind that may affect performance quite a bit if you are sending the output to a file. Also keep in mind that support for this is implementation-defined, not guaranteed by the standard.

ISO C99 section 7.19.3/3 is the relevant bit:

When a stream is unbuffered, characters are intended to appear from the source or at the destination as soon as possible. Otherwise characters may be accumulated and transmitted to or from the host environment as a block.

When a stream is fully buffered, characters are intended to be transmitted to or from the host environment as a block when a buffer is filled.

When a stream is line buffered, characters are intended to be transmitted to or from the host environment as a block when a new-line character is encountered.

Furthermore, characters are intended to be transmitted as a block to the host environment when a buffer is filled, when input is requested on an unbuffered stream, or when input is requested on a line buffered stream that requires the transmission of characters from the host environment.

Support for these characteristics is implementation-defined, and may be affected via the setbuf and setvbuf functions.