Programs & Examples On #Warning level

A compiler option that controls which warnings the compiler issues

How to plot a 2D FFT in Matlab?

Assuming that I is your input image and F is its Fourier Transform (i.e. F = fft2(I))

You can use this code:

F = fftshift(F); % Center FFT

F = abs(F); % Get the magnitude
F = log(F+1); % Use log, for perceptual scaling, and +1 since log(0) is undefined
F = mat2gray(F); % Use mat2gray to scale the image between 0 and 1

imshow(F,[]); % Display the result

How do I break a string in YAML over multiple lines?

For situations were the string might contain spaces or not, I prefer double quotes and line continuation with backslashes:

key: "String \
  with long c\
  ontent"

But note about the pitfall for the case that a continuation line begins with a space, it needs to be escaped (because it will be stripped away elsewhere):

key: "String\
  \ with lon\
  g content"

If the string contains line breaks, this needs to be written in C style \n.

See also this question.

No connection could be made because the target machine actively refused it (PHP / WAMP)

Till yesterday I was able to connect to phpMyAdmin, but today I started getting this error:

2002-no-connection-could-be-made-because-the-target-machine-actively-refused

None of the answers here really helped me fix the problem, what helped me is shared below:

I looked at the mysql logs.[C:\wamp\logs\mysql.log]

It said

2015-09-18 01:16:30 5920 [Note] Plugin 'FEDERATED' is disabled.
2015-09-18 01:16:30 5920 [Note] InnoDB: Using atomics to ref count buffer pool pages
2015-09-18 01:16:30 5920 [Note] InnoDB: The InnoDB memory heap is disabled
2015-09-18 01:16:30 5920 [Note] InnoDB: Mutexes and rw_locks use Windows interlocked functions
2015-09-18 01:16:30 5920 [Note] InnoDB: Compressed tables use zlib 1.2.3
2015-09-18 01:16:30 5920 [Note] InnoDB: Not using CPU crc32 instructions
2015-09-18 01:16:30 5920 [Note] InnoDB: Initializing buffer pool, size = 128.0M
2015-09-18 01:16:30 5920 [Note] InnoDB: Completed initialization of buffer pool
2015-09-18 01:16:30 5920 [Note] InnoDB: Highest supported file format is Barracuda.
2015-09-18 01:16:30 5920 [Note] InnoDB: The log sequence numbers 1765410 and 1765410 in ibdata files do not match the log sequence number 2058233 in the ib_logfiles!
2015-09-18 01:16:30 5920 [Note] InnoDB: Database was not shutdown normally!
2015-09-18 01:16:30 5920 [Note] InnoDB: Starting crash recovery.
2015-09-18 01:16:30 5920 [Note] InnoDB: Reading tablespace information from the .ibd files...
2015-09-18 01:16:30 5920 [ERROR] InnoDB: Attempted to open a previously opened tablespace. Previous tablespace harley/login_confirm uses space ID: 6 at filepath: .\harley\login_confirm.ibd. Cannot open tablespace testdb/testtable which uses space ID: 6 at filepath: .\testdb\testtable.ibd
InnoDB: Error: could not open single-table tablespace file .\testdb\testtable.ibd
InnoDB: We do not continue the crash recovery, because the table may become
InnoDB: corrupt if we cannot apply the log records in the InnoDB log to it.
InnoDB: To fix the problem and start mysqld:
InnoDB: 1) If there is a permission problem in the file and mysqld cannot
InnoDB: open the file, you should modify the permissions.
InnoDB: 2) If the table is not needed, or you can restore it from a backup,
InnoDB: then you can remove the .ibd file, and InnoDB will do a normal
InnoDB: crash recovery and ignore that table.
InnoDB: 3) If the file system or the disk is broken, and you cannot remove
InnoDB: the .ibd file, you can set innodb_force_recovery > 0 in my.cnf
InnoDB: and force InnoDB to continue crash recovery here.

I got the clue that this guy is creating a problem - InnoDB: Error: could not open single-table tablespace file .\testdb\testtable.ibd

and this line 2015-09-18 01:16:30 5920 [Note] InnoDB: Database was not shutdown normally!

hmmm, For me the testdb was just a test-db! hence I decided to delete this file inside C:\wamp\bin\mysql\mysql5.6.17\data\testdb

and restarted all services, and went to phpMyAdmin, and this time no issues, phpMyAdmin opened :)

How do I go about adding an image into a java project with eclipse?

If you still have problems with Eclipse finding your files, you might try the following:

  1. Verify that the file exists according to the current execution environment by using the java.io.File class to get a canonical path format and verify that (a) the file exists and (b) what the canonical path is.
  2. Verify the default working directory by printing the following in your main:

        System.out.println("Working dir:  " + System.getProperty("user.dir"));
    

For (1) above, I put the following debugging code around the specific file I was trying to access:

            File imageFile = new File(source);
            System.out.println("Canonical path of target image: " + imageFile.getCanonicalPath());
            if (!imageFile.exists()) {
                System.out.println("file " + imageFile + " does not exist");
            }
            image = ImageIO.read(imageFile);                

For whatever reason, I ended up ignoring most of the other posts telling me to put the image files in "src" or some other variant, as I verified that the system was looking at the root of the Eclipse project directory hierarchy (e.g., $HOME/workspace/myProject).

Having the images in src/ (which is automatically copied to bin/) didn't do the trick on Eclipse Luna.

Can overridden methods differ in return type?

Broadly speaking yes return type of overriding method can be different. But it's not straight forward as there are some cases involved in this.

Case 1: If the return type is a primitive data type or void.

Output: If the return type is void or primitive then the data type of parent class method and overriding method should be the same. e.g. if the return type is int, float, string then it should be same

Case 2: If the return type is derived data type:

Output: If the return type of the parent class method is derived type then the return type of the overriding method is the same derived data type of subclass to the derived data type. e.g. Suppose I have a class A, B is a subclass to A, C is a subclass to B and D is a subclass to C; then if the super class is returning type A then the overriding method in subclass can return either A, or B/C/D type i.e. its sub types. This is also called as covariance.

how to display variable value in alert box?

spans not have the value in html

one is the id for span tag

in javascript use

document.getElementById('one').innerText;

in jQuery use

$('#one').text()

function check() {
    var content = document.getElementById("one").innerText;
    alert(content);
}

or

function check() {
        var content = $('#one').text();
        alert(content);
    }

Best timing method in C?

I think this should work:

#include <time.h>

clock_t start = clock(), diff;
ProcessIntenseFunction();
diff = clock() - start;

int msec = diff * 1000 / CLOCKS_PER_SEC;
printf("Time taken %d seconds %d milliseconds", msec/1000, msec%1000);

Environment variable in Jenkins Pipeline

To avoid problems of side effects after changing env, especially using multiple nodes, it is better to set a temporary context.

One safe way to alter the environment is:

 withEnv(['MYTOOL_HOME=/usr/local/mytool']) {
    sh '$MYTOOL_HOME/bin/start'
 }

This approach does not poison the env after the command execution.

Efficient way to return a std::vector in c++

You should return by value.

The standard has a specific feature to improve the efficiency of returning by value. It's called "copy elision", and more specifically in this case the "named return value optimization (NRVO)".

Compilers don't have to implement it, but then again compilers don't have to implement function inlining (or perform any optimization at all). But the performance of the standard libraries can be pretty poor if compilers don't optimize, and all serious compilers implement inlining and NRVO (and other optimizations).

When NRVO is applied, there will be no copying in the following code:

std::vector<int> f() {
    std::vector<int> result;
    ... populate the vector ...
    return result;
}

std::vector<int> myvec = f();

But the user might want to do this:

std::vector<int> myvec;
... some time later ...
myvec = f();

Copy elision does not prevent a copy here because it's an assignment rather than an initialization. However, you should still return by value. In C++11, the assignment is optimized by something different, called "move semantics". In C++03, the above code does cause a copy, and although in theory an optimizer might be able to avoid it, in practice its too difficult. So instead of myvec = f(), in C++03 you should write this:

std::vector<int> myvec;
... some time later ...
f().swap(myvec);

There is another option, which is to offer a more flexible interface to the user:

template <typename OutputIterator> void f(OutputIterator it) {
    ... write elements to the iterator like this ...
    *it++ = 0;
    *it++ = 1;
}

You can then also support the existing vector-based interface on top of that:

std::vector<int> f() {
    std::vector<int> result;
    f(std::back_inserter(result));
    return result;
}

This might be less efficient than your existing code, if your existing code uses reserve() in a way more complex than just a fixed amount up front. But if your existing code basically calls push_back on the vector repeatedly, then this template-based code ought to be as good.

Is there a typescript List<> and/or Map<> class/library?

It's very easy to write that yourself, and that way you have more control over things.. As the other answers say, TypeScript is not aimed at adding runtime types or functionality.

Map:

class Map<T> {
    private items: { [key: string]: T };

    constructor() {
        this.items = {};
    }

    add(key: string, value: T): void {
        this.items[key] = value;
    }

    has(key: string): boolean {
        return key in this.items;
    }

    get(key: string): T {
        return this.items[key];
    }
}

List:

class List<T> {
    private items: Array<T>;

    constructor() {
        this.items = [];
    }

    size(): number {
        return this.items.length;
    }

    add(value: T): void {
        this.items.push(value);
    }

    get(index: number): T {
        return this.items[index];
    }
}

I haven't tested (or even tried to compile) this code, but it should give you a starting point.. you can of course then change what ever you want and add the functionality that YOU need...

As for your "special needs" from the List, I see no reason why to implement a linked list, since the javascript array lets you add and remove items.
Here's a modified version of the List to handle the get prev/next from the element itself:

class ListItem<T> {
    private list: List<T>;
    private index: number;

    public value: T;

    constructor(list: List<T>, value: T, index: number) {
        this.list = list;
        this.index = index;
        this.value = value;
    }

    prev(): ListItem<T> {
        return this.list.get(this.index - 1);
    }

    next(): ListItem<T> {
        return this.list.get(this.index + 1);   
    }
}

class List<T> {
    private items: Array<ListItem<T>>;

    constructor() {
        this.items = [];
    }

    size(): number {
        return this.items.length;
    }

    add(value: T): void {
        this.items.push(new ListItem<T>(this, value, this.size()));
    }

    get(index: number): ListItem<T> {
        return this.items[index];
    }
}

Here too you're looking at untested code..

Hope this helps.


Edit - as this answer still gets some attention

Javascript has a native Map object so there's no need to create your own:

let map = new Map();
map.set("key1", "value1");
console.log(map.get("key1")); // value1

'Incomplete final line' warning when trying to read a .csv file into R

I realized that several answers have been provided but no real fix yet.

The reason, as mentioned above, is a "End of line" missing at the end of the CSV file.

While the real Fix should come from Microsoft, the walk around is to open the CSV file with a Text-editor and add a line at the end of the file (aka press return key). I use ATOM software as a text/code editor but virtually all basic text editor would do.

In the meanwhile, please report the bug to Microsoft.

Question: It seems to me that it is a office 2016 problem. Does anyone have the issue on a PC?

How to convert a std::string to const char* or char*?

If you just want to pass a std::string to a function that needs const char* you can use

std::string str;
const char * c = str.c_str();

If you want to get a writable copy, like char *, you can do that with this:

std::string str;
char * writable = new char[str.size() + 1];
std::copy(str.begin(), str.end(), writable);
writable[str.size()] = '\0'; // don't forget the terminating 0

// don't forget to free the string after finished using it
delete[] writable;

Edit: Notice that the above is not exception safe. If anything between the new call and the delete call throws, you will leak memory, as nothing will call delete for you automatically. There are two immediate ways to solve this.

boost::scoped_array

boost::scoped_array will delete the memory for you upon going out of scope:

std::string str;
boost::scoped_array<char> writable(new char[str.size() + 1]);
std::copy(str.begin(), str.end(), writable.get());
writable[str.size()] = '\0'; // don't forget the terminating 0

// get the char* using writable.get()

// memory is automatically freed if the smart pointer goes 
// out of scope

std::vector

This is the standard way (does not require any external library). You use std::vector, which completely manages the memory for you.

std::string str;
std::vector<char> writable(str.begin(), str.end());
writable.push_back('\0');

// get the char* using &writable[0] or &*writable.begin()

Entity Framework 6 GUID as primary key: Cannot insert the value NULL into column 'Id', table 'FileStore'; column does not allow nulls

If you do Code-First and already have a Database:

public override void Up()
{
    AlterColumn("dbo.MyTable","Id", c =>  c.Guid(nullable: false, identity: true, defaultValueSql: "newsequentialid()"));
}

How do I call a specific Java method on a click/submit event of a specific button in JSP?

You can try adding action="#{yourBean.function1}" on each button (changing of course the method function2, function3, or whatever you need). If that does not work, you can try the same with the onclick event.

Anyway, it would be easier to help you if you tell us what kind of buttons are you trying to use, a4j:commandButton or whatever you are using.

"And" and "Or" troubles within an IF statement

This is not an answer, but too long for a comment.

In reply to JP's answers / comments, I have run the following test to compare the performance of the 2 methods. The Profiler object is a custom class - but in summary, it uses a kernel32 function which is fairly accurate (Private Declare Sub GetLocalTime Lib "kernel32" (lpSystemTime As SYSTEMTIME)).

Sub test()

  Dim origNum As String
  Dim creditOrDebit As String
  Dim b As Boolean
  Dim p As Profiler
  Dim i As Long

  Set p = New_Profiler

  origNum = "30062600006"
  creditOrDebit = "D"

  p.startTimer ("nested_ifs")

  For i = 1 To 1000000

    If creditOrDebit = "D" Then
      If origNum = "006260006" Then
        b = True
      ElseIf origNum = "30062600006" Then
        b = True
      End If
    End If

  Next i

  p.stopTimer ("nested_ifs")
  p.startTimer ("or_and")

  For i = 1 To 1000000

    If (origNum = "006260006" Or origNum = "30062600006") And creditOrDebit = "D" Then
      b = True
    End If

  Next i

  p.stopTimer ("or_and")

  p.printReport

End Sub

The results of 5 runs (in ms for 1m loops):

20-Jun-2012 19:28:25
nested_ifs (x1): 156 - Last Run: 156 - Average Run: 156
or_and (x1): 125 - Last Run: 125 - Average Run: 125

20-Jun-2012 19:28:26
nested_ifs (x1): 156 - Last Run: 156 - Average Run: 156
or_and (x1): 125 - Last Run: 125 - Average Run: 125

20-Jun-2012 19:28:27
nested_ifs (x1): 140 - Last Run: 140 - Average Run: 140
or_and (x1): 125 - Last Run: 125 - Average Run: 125

20-Jun-2012 19:28:28
nested_ifs (x1): 140 - Last Run: 140 - Average Run: 140
or_and (x1): 141 - Last Run: 141 - Average Run: 141

20-Jun-2012 19:28:29
nested_ifs (x1): 156 - Last Run: 156 - Average Run: 156
or_and (x1): 125 - Last Run: 125 - Average Run: 125

Note

If creditOrDebit is not "D", JP's code runs faster (around 60ms vs. 125ms for the or/and code).

C# DLL config file

if you want to read settings from the DLL's config file but not from the the root applications web.config or app.config use below code to read configuration in the dll.

var appConfig = ConfigurationManager.OpenExeConfiguration(Assembly.GetExecutingAssembly().Location);
string dllConfigData = appConfig.AppSettings.Settings["dllConfigData"].Value;

What is a Java String's default initial value?

There are three types of variables:

  • Instance variables: are always initialized
  • Static variables: are always initialized
  • Local variables: must be initialized before use

The default values for instance and static variables are the same and depends on the type:

  • Object type (String, Integer, Boolean and others): initialized with null
  • Primitive types:
    • byte, short, int, long: 0
    • float, double: 0.0
    • boolean: false
    • char: '\u0000'

An array is an Object. So an array instance variable that is declared but no explicitly initialized will have null value. If you declare an int[] array as instance variable it will have the null value.

Once the array is created all of its elements are assiged with the default type value. For example:

private boolean[] list; // default value is null

private Boolean[] list; // default value is null

once is initialized:

private boolean[] list = new boolean[10]; // all ten elements are assigned to false

private Boolean[] list = new Boolean[10]; // all ten elements are assigned to null (default Object/Boolean value)

Trying to git pull with error: cannot open .git/FETCH_HEAD: Permission denied

Try like this way,

Step 1: First check who you are? it will return current user name e.g ubuntu

$ whoami 

Step 2: Then set permission to your current user, in that case, ubuntu by

sudo chown -R ubuntu .git/

Looking for a 'cmake clean' command to clear up CMake output

Maybe it's a little outdated, but since this is the first hit when you google cmake clean, I will add this:

Since you can start a build in the build dir with a specified target with

cmake --build . --target xyz

you can of course run

cmake --build . --target clean

to run the clean target in the generated build files.

GLYPHICONS - bootstrap icon font hex value

We can find these by looking at Bootstrap's stylesheet, Bootstrap.css. Each \{number} represents a hexadecimal value, so \2a is equal to 0x2a or &#x2a;.

As for the font, that can be downloaded from http://glyphicons.com.

.glyphicon-asterisk:before {
  content: "\2a";
}

.glyphicon-plus:before {
  content: "\2b";
}

.glyphicon-euro:before {
  content: "\20ac";
}

.glyphicon-minus:before {
  content: "\2212";
}

.glyphicon-cloud:before {
  content: "\2601";
}

.glyphicon-envelope:before {
  content: "\2709";
}

.glyphicon-pencil:before {
  content: "\270f";
}

.glyphicon-glass:before {
  content: "\e001";
}

.glyphicon-music:before {
  content: "\e002";
}

.glyphicon-search:before {
  content: "\e003";
}

.glyphicon-heart:before {
  content: "\e005";
}

.glyphicon-star:before {
  content: "\e006";
}

.glyphicon-star-empty:before {
  content: "\e007";
}

.glyphicon-user:before {
  content: "\e008";
}

.glyphicon-film:before {
  content: "\e009";
}

.glyphicon-th-large:before {
  content: "\e010";
}

.glyphicon-th:before {
  content: "\e011";
}

.glyphicon-th-list:before {
  content: "\e012";
}

.glyphicon-ok:before {
  content: "\e013";
}

.glyphicon-remove:before {
  content: "\e014";
}

.glyphicon-zoom-in:before {
  content: "\e015";
}

.glyphicon-zoom-out:before {
  content: "\e016";
}

.glyphicon-off:before {
  content: "\e017";
}

.glyphicon-signal:before {
  content: "\e018";
}

.glyphicon-cog:before {
  content: "\e019";
}

.glyphicon-trash:before {
  content: "\e020";
}

.glyphicon-home:before {
  content: "\e021";
}

.glyphicon-file:before {
  content: "\e022";
}

.glyphicon-time:before {
  content: "\e023";
}

.glyphicon-road:before {
  content: "\e024";
}

.glyphicon-download-alt:before {
  content: "\e025";
}

.glyphicon-download:before {
  content: "\e026";
}

.glyphicon-upload:before {
  content: "\e027";
}

.glyphicon-inbox:before {
  content: "\e028";
}

.glyphicon-play-circle:before {
  content: "\e029";
}

.glyphicon-repeat:before {
  content: "\e030";
}

.glyphicon-refresh:before {
  content: "\e031";
}

.glyphicon-list-alt:before {
  content: "\e032";
}

.glyphicon-lock:before {
  content: "\e033";
}

.glyphicon-flag:before {
  content: "\e034";
}

.glyphicon-headphones:before {
  content: "\e035";
}

.glyphicon-volume-off:before {
  content: "\e036";
}

.glyphicon-volume-down:before {
  content: "\e037";
}

.glyphicon-volume-up:before {
  content: "\e038";
}

.glyphicon-qrcode:before {
  content: "\e039";
}

.glyphicon-barcode:before {
  content: "\e040";
}

.glyphicon-tag:before {
  content: "\e041";
}

.glyphicon-tags:before {
  content: "\e042";
}

.glyphicon-book:before {
  content: "\e043";
}

.glyphicon-bookmark:before {
  content: "\e044";
}

.glyphicon-print:before {
  content: "\e045";
}

.glyphicon-camera:before {
  content: "\e046";
}

.glyphicon-font:before {
  content: "\e047";
}

.glyphicon-bold:before {
  content: "\e048";
}

.glyphicon-italic:before {
  content: "\e049";
}

.glyphicon-text-height:before {
  content: "\e050";
}

.glyphicon-text-width:before {
  content: "\e051";
}

.glyphicon-align-left:before {
  content: "\e052";
}

.glyphicon-align-center:before {
  content: "\e053";
}

.glyphicon-align-right:before {
  content: "\e054";
}

.glyphicon-align-justify:before {
  content: "\e055";
}

.glyphicon-list:before {
  content: "\e056";
}

.glyphicon-indent-left:before {
  content: "\e057";
}

.glyphicon-indent-right:before {
  content: "\e058";
}

.glyphicon-facetime-video:before {
  content: "\e059";
}

.glyphicon-picture:before {
  content: "\e060";
}

.glyphicon-map-marker:before {
  content: "\e062";
}

.glyphicon-adjust:before {
  content: "\e063";
}

.glyphicon-tint:before {
  content: "\e064";
}

.glyphicon-edit:before {
  content: "\e065";
}

.glyphicon-share:before {
  content: "\e066";
}

.glyphicon-check:before {
  content: "\e067";
}

.glyphicon-move:before {
  content: "\e068";
}

.glyphicon-step-backward:before {
  content: "\e069";
}

.glyphicon-fast-backward:before {
  content: "\e070";
}

.glyphicon-backward:before {
  content: "\e071";
}

.glyphicon-play:before {
  content: "\e072";
}

.glyphicon-pause:before {
  content: "\e073";
}

.glyphicon-stop:before {
  content: "\e074";
}

.glyphicon-forward:before {
  content: "\e075";
}

.glyphicon-fast-forward:before {
  content: "\e076";
}

.glyphicon-step-forward:before {
  content: "\e077";
}

.glyphicon-eject:before {
  content: "\e078";
}

.glyphicon-chevron-left:before {
  content: "\e079";
}

.glyphicon-chevron-right:before {
  content: "\e080";
}

.glyphicon-plus-sign:before {
  content: "\e081";
}

.glyphicon-minus-sign:before {
  content: "\e082";
}

.glyphicon-remove-sign:before {
  content: "\e083";
}

.glyphicon-ok-sign:before {
  content: "\e084";
}

.glyphicon-question-sign:before {
  content: "\e085";
}

.glyphicon-info-sign:before {
  content: "\e086";
}

.glyphicon-screenshot:before {
  content: "\e087";
}

.glyphicon-remove-circle:before {
  content: "\e088";
}

.glyphicon-ok-circle:before {
  content: "\e089";
}

.glyphicon-ban-circle:before {
  content: "\e090";
}

.glyphicon-arrow-left:before {
  content: "\e091";
}

.glyphicon-arrow-right:before {
  content: "\e092";
}

.glyphicon-arrow-up:before {
  content: "\e093";
}

.glyphicon-arrow-down:before {
  content: "\e094";
}

.glyphicon-share-alt:before {
  content: "\e095";
}

.glyphicon-resize-full:before {
  content: "\e096";
}

.glyphicon-resize-small:before {
  content: "\e097";
}

.glyphicon-exclamation-sign:before {
  content: "\e101";
}

.glyphicon-gift:before {
  content: "\e102";
}

.glyphicon-leaf:before {
  content: "\e103";
}

.glyphicon-fire:before {
  content: "\e104";
}

.glyphicon-eye-open:before {
  content: "\e105";
}

.glyphicon-eye-close:before {
  content: "\e106";
}

.glyphicon-warning-sign:before {
  content: "\e107";
}

.glyphicon-plane:before {
  content: "\e108";
}

.glyphicon-calendar:before {
  content: "\e109";
}

.glyphicon-random:before {
  content: "\e110";
}

.glyphicon-comment:before {
  content: "\e111";
}

.glyphicon-magnet:before {
  content: "\e112";
}

.glyphicon-chevron-up:before {
  content: "\e113";
}

.glyphicon-chevron-down:before {
  content: "\e114";
}

.glyphicon-retweet:before {
  content: "\e115";
}

.glyphicon-shopping-cart:before {
  content: "\e116";
}

.glyphicon-folder-close:before {
  content: "\e117";
}

.glyphicon-folder-open:before {
  content: "\e118";
}

.glyphicon-resize-vertical:before {
  content: "\e119";
}

.glyphicon-resize-horizontal:before {
  content: "\e120";
}

.glyphicon-hdd:before {
  content: "\e121";
}

.glyphicon-bullhorn:before {
  content: "\e122";
}

.glyphicon-bell:before {
  content: "\e123";
}

.glyphicon-certificate:before {
  content: "\e124";
}

.glyphicon-thumbs-up:before {
  content: "\e125";
}

.glyphicon-thumbs-down:before {
  content: "\e126";
}

.glyphicon-hand-right:before {
  content: "\e127";
}

.glyphicon-hand-left:before {
  content: "\e128";
}

.glyphicon-hand-up:before {
  content: "\e129";
}

.glyphicon-hand-down:before {
  content: "\e130";
}

.glyphicon-circle-arrow-right:before {
  content: "\e131";
}

.glyphicon-circle-arrow-left:before {
  content: "\e132";
}

.glyphicon-circle-arrow-up:before {
  content: "\e133";
}

.glyphicon-circle-arrow-down:before {
  content: "\e134";
}

.glyphicon-globe:before {
  content: "\e135";
}

.glyphicon-wrench:before {
  content: "\e136";
}

.glyphicon-tasks:before {
  content: "\e137";
}

.glyphicon-filter:before {
  content: "\e138";
}

.glyphicon-briefcase:before {
  content: "\e139";
}

.glyphicon-fullscreen:before {
  content: "\e140";
}

.glyphicon-dashboard:before {
  content: "\e141";
}

.glyphicon-paperclip:before {
  content: "\e142";
}

.glyphicon-heart-empty:before {
  content: "\e143";
}

.glyphicon-link:before {
  content: "\e144";
}

.glyphicon-phone:before {
  content: "\e145";
}

.glyphicon-pushpin:before {
  content: "\e146";
}

.glyphicon-usd:before {
  content: "\e148";
}

.glyphicon-gbp:before {
  content: "\e149";
}

.glyphicon-sort:before {
  content: "\e150";
}

.glyphicon-sort-by-alphabet:before {
  content: "\e151";
}

.glyphicon-sort-by-alphabet-alt:before {
  content: "\e152";
}

.glyphicon-sort-by-order:before {
  content: "\e153";
}

.glyphicon-sort-by-order-alt:before {
  content: "\e154";
}

.glyphicon-sort-by-attributes:before {
  content: "\e155";
}

.glyphicon-sort-by-attributes-alt:before {
  content: "\e156";
}

.glyphicon-unchecked:before {
  content: "\e157";
}

.glyphicon-expand:before {
  content: "\e158";
}

.glyphicon-collapse-down:before {
  content: "\e159";
}

.glyphicon-collapse-up:before {
  content: "\e160";
}

.glyphicon-log-in:before {
  content: "\e161";
}

.glyphicon-flash:before {
  content: "\e162";
}

.glyphicon-log-out:before {
  content: "\e163";
}

.glyphicon-new-window:before {
  content: "\e164";
}

.glyphicon-record:before {
  content: "\e165";
}

.glyphicon-save:before {
  content: "\e166";
}

.glyphicon-open:before {
  content: "\e167";
}

.glyphicon-saved:before {
  content: "\e168";
}

.glyphicon-import:before {
  content: "\e169";
}

.glyphicon-export:before {
  content: "\e170";
}

.glyphicon-send:before {
  content: "\e171";
}

.glyphicon-floppy-disk:before {
  content: "\e172";
}

.glyphicon-floppy-saved:before {
  content: "\e173";
}

.glyphicon-floppy-remove:before {
  content: "\e174";
}

.glyphicon-floppy-save:before {
  content: "\e175";
}

.glyphicon-floppy-open:before {
  content: "\e176";
}

.glyphicon-credit-card:before {
  content: "\e177";
}

.glyphicon-transfer:before {
  content: "\e178";
}

.glyphicon-cutlery:before {
  content: "\e179";
}

.glyphicon-header:before {
  content: "\e180";
}

.glyphicon-compressed:before {
  content: "\e181";
}

.glyphicon-earphone:before {
  content: "\e182";
}

.glyphicon-phone-alt:before {
  content: "\e183";
}

.glyphicon-tower:before {
  content: "\e184";
}

.glyphicon-stats:before {
  content: "\e185";
}

.glyphicon-sd-video:before {
  content: "\e186";
}

.glyphicon-hd-video:before {
  content: "\e187";
}

.glyphicon-subtitles:before {
  content: "\e188";
}

.glyphicon-sound-stereo:before {
  content: "\e189";
}

.glyphicon-sound-dolby:before {
  content: "\e190";
}

.glyphicon-sound-5-1:before {
  content: "\e191";
}

.glyphicon-sound-6-1:before {
  content: "\e192";
}

.glyphicon-sound-7-1:before {
  content: "\e193";
}

.glyphicon-copyright-mark:before {
  content: "\e194";
}

.glyphicon-registration-mark:before {
  content: "\e195";
}

.glyphicon-cloud-download:before {
  content: "\e197";
}

.glyphicon-cloud-upload:before {
  content: "\e198";
}

.glyphicon-tree-conifer:before {
  content: "\e199";
}

.glyphicon-tree-deciduous:before {
  content: "\e200";
}

The requested resource does not support HTTP method 'GET'

Please use the attributes from the System.Web.Http namespace on your WebAPI actions:

    [System.Web.Http.AcceptVerbs("GET", "POST")]
    [System.Web.Http.HttpGet]
    public string Auth(string username, string password)
    {...}

The reason why it doesn't work is because you were using the attributes that are from the MVC namespace System.Web.Mvc. The classes in the System.Web.Http namespace are for WebAPI.

Iterate through 2 dimensional array

Simple idea: get the lenght of the longest row, iterate over each column printing the content of a row if it has elements. The below code might have some off-by-one errors as it was coded in a simple text editor.

  int longestRow = 0;
  for (int i = 0; i < array.length; i++) {
    if (array[i].length > longestRow) {
      longestRow = array[i].length;
    }
  }

  for (int j = 0; j < longestRow; j++) {
    for (int i = 0; i < array.length; i++) {
      if(array[i].length > j) {
        System.out.println(array[i][j]);
      }
    }
  }

Javascript how to split newline

_x000D_
_x000D_
(function($) {_x000D_
  $(document).ready(function() {_x000D_
    $('#data').click(function(e) {_x000D_
      e.preventDefault();_x000D_
      $.each($("#keywords").val().split("\n"), function(e, element) {_x000D_
        alert(element);_x000D_
      });_x000D_
    });_x000D_
  });_x000D_
})(jQuery);
_x000D_
<script src="https://cdnjs.cloudflare.com/ajax/libs/jquery/3.3.1/jquery.min.js"></script>_x000D_
_x000D_
<textarea id="keywords">Hello_x000D_
World</textarea>_x000D_
<input id="data" type="button" value="submit">
_x000D_
_x000D_
_x000D_

convert 12-hour hh:mm AM/PM to 24-hour hh:mm

I had to do something similar but I was generating a Date object so I ended up making a function like this:

function convertTo24Hour(time) {
    var hours = parseInt(time.substr(0, 2));
    if(time.indexOf('am') != -1 && hours == 12) {
        time = time.replace('12', '0');
    }
    if(time.indexOf('pm')  != -1 && hours < 12) {
        time = time.replace(hours, (hours + 12));
    }
    return time.replace(/(am|pm)/, '');
}

I think this reads a little easier. You feed a string in the format h:mm am/pm.

    var time = convertTo24Hour($("#starttime").val().toLowerCase());
    var date = new Date($("#startday").val() + ' ' + time);

Examples:

        $("#startday").val('7/10/2013');

        $("#starttime").val('12:00am');
        new Date($("#startday").val() + ' ' + convertTo24Hour($("#starttime").val().toLowerCase()));
        Wed Jul 10 2013 00:00:00 GMT-0700 (PDT)

        $("#starttime").val('12:00pm');
        new Date($("#startday").val() + ' ' + convertTo24Hour($("#starttime").val().toLowerCase()));
        Wed Jul 10 2013 12:00:00 GMT-0700 (PDT)

        $("#starttime").val('1:00am');
        new Date($("#startday").val() + ' ' + convertTo24Hour($("#starttime").val().toLowerCase()));
        Wed Jul 10 2013 01:00:00 GMT-0700 (PDT)

        $("#starttime").val('12:12am');
        new Date($("#startday").val() + ' ' + convertTo24Hour($("#starttime").val().toLowerCase()));
        Wed Jul 10 2013 00:12:00 GMT-0700 (PDT)

        $("#starttime").val('3:12am');
        new Date($("#startday").val() + ' ' + convertTo24Hour($("#starttime").val().toLowerCase()));
        Wed Jul 10 2013 03:12:00 GMT-0700 (PDT)

        $("#starttime").val('9:12pm');
        new Date($("#startday").val() + ' ' + convertTo24Hour($("#starttime").val().toLowerCase()));
        Wed Jul 10 2013 21:12:00 GMT-0700 (PDT)

Python concatenate text files

Use shutil.copyfileobj.

It automatically reads the input files chunk by chunk for you, which is more more efficient and reading the input files in and will work even if some of the input files are too large to fit into memory:

import shutil

with open('output_file.txt','wb') as wfd:
    for f in ['seg1.txt','seg2.txt','seg3.txt']:
        with open(f,'rb') as fd:
            shutil.copyfileobj(fd, wfd)

What is an 'undeclared identifier' error and how do I fix it?

These error meassages

1.For the Visual Studio compiler: error C2065: 'printf' : undeclared identifier
2.For the GCC compiler: `printf' undeclared (first use in this function)

mean that you use name printf but the compiler does not see where the name was declared and accordingly does not know what it means.

Any name used in a program shall be declared before its using. The compiler has to know what the name denotes.

In this particular case the compiler does not see the declaration of name printf . As we know (but not the compiler) it is the name of standard C function declared in header <stdio.h> in C or in header <cstdio> in C++ and placed in standard (std::) and global (::) (not necessarily) name spaces.

So before using this function we have to provide its name declaration to the compiler by including corresponding headers.

For example C:

#include <stdio.h>

int main( void )
{
   printf( "Hello World\n" );
}

C++:

#include <cstdio>

int main()
{
   std::printf( "Hello World\n" );
   // or printf( "Hello World\n" );
   // or ::printf( "Hello World\n" );
}

Sometimes the reason of such an error is a simple typo. For example let's assume that you defined function PrintHello

void PrintHello()
{
    std::printf( "Hello World\n" );
}

but in main you made a typo and instead of PrintHello you typed printHello with lower case letter 'p'.

#include <cstdio>

void PrintHello()
{
    std::printf( "Hello World\n" );
}

int main()
{
   printHello();
}

In this case the compiler will issue such an error because it does not see the declaration of name printHello. PrintHello and printHello are two different names one of which was declared and other was not declared but used in the body of main

Creating a "logical exclusive or" operator in Java

I am using the very popular class "org.apache.commons.lang.BooleanUtils"

This method is tested by many users and safe. Have fun. Usage:

boolean result =BooleanUtils.xor(new boolean[]{true,false});

How do I make a newline after a twitter bootstrap element?

Using br elements is fine, and as long as you don't need a lot of space between elements, is actually a logical thing to do as anyone can read your code and understand what spacing logic you are using.

The alternative is to create a custom class for white space. In bootstrap 4 you can use

<div class="w-100"></div>

to make a blank row across the page, but this is no different to using the <br> tag. The downside to creating a custom class for white space is that it can be a pain to read for others who view your code. A custom class would also apply the same amount of white space each time you used it, so if you wanted different amounts of white space on the same page, then you would need to create several white space classes.

In most cases, it is just easier to use <br> or <div class="w-100"></div> for the sake of ease and readability. it doesn't look pretty, but it works.

How to attach a file using mail command on Linux?

Example using uuencode:

uuencode surfing.jpeg surfing.jpeg | mail [email protected]

and reference article:

http://www.shelldorado.com/articles/mailattachments.html

Note:

you may apt install sharutils to have uuencode command

Change UITableView height dynamically

Use simple and easy code

func tableView(tableView: UITableView, heightForRowAtIndexPath indexPath: NSIndexPath) -> CGFloat {
        let myCell = tableView.dequeueReusableCellWithIdentifier("mannaCustumCell") as! CustomCell
        let heightForCell = myCell.bounds.size.height;

        return heightForCell;
    }

How to run console application from Windows Service?

I have a Windows service, and I added the following line to the constructor for my service:

using System.Diagnostics;
try {
    Process p = Process.Start(@"C:\Windows\system32\calc.exe");
} catch {
    Debugger.Break();
}

When I tried to run this, the Process.Start() call was made, and no exception occurred. However, the calc.exe application did not show up. In order to make it work, I had edit the properties for my service in the Service Control Manager to enable interaction with the desktop. After doing that, the Process.Start() opened calc.exe as expected.

But as others have said, interaction with the desktop is frowned upon by Microsoft and has essentially been disabled in Vista. So even if you can get it to work in XP, I don't know that you'll be able to make it work in Vista.

Integer.valueOf() vs. Integer.parseInt()

First Question: Difference between parseInt and valueOf in java?

Second Question:

NumberFormat format = NumberFormat.getInstance(Locale.FRANCE);
Number number = format.parse("1,234");
double d = number.doubleValue();

Third Question:

DecimalFormat df = new DecimalFormat();
DecimalFormatSymbols symbols = new DecimalFormatSymbols();
symbols.setDecimalSeparator('.');
symbols.setGroupingSeparator(',');
df.setDecimalFormatSymbols(symbols);
df.parse(p);

java.lang.ClassNotFoundException: org.apache.xmlbeans.XmlObject Error

You have to include one more jar.

xmlbeans-2.3.0.jar

Add this and try.

Note: It is required for the files with .xlsx formats only, not for just .xls formats.

How do you uninstall a python package that was installed using distutils?

Yes, it is safe to simply delete anything that distutils installed. That goes for installed folders or .egg files. Naturally anything that depends on that code will no longer work.

If you want to make it work again, simply re-install.

By the way, if you are using distutils also consider using the multi-version feature. It allows you to have multiple versions of any single package installed. That means you do not need to delete an old version of a package if you simply want to install a newer version.

A Generic error occurred in GDI+ in Bitmap.Save method

I always check/test these:

  • Does the path + filename contain illegal characters for the given filesystem?
  • Does the file already exist? (Bad)
  • Does the path already exist? (Good)
  • If the path is relative: am I expecting it in the right parent directory (mostly bin/Debug ;-) )?
  • Is the path writable for the program and as which user does it run? (Services can be tricky here!)
  • Does the full path really, really not contain illegal chars? (some unicode chars are close to invisible)

I never had any problems with Bitmap.Save() apart from this list.

@RequestBody and @ResponseBody annotations in Spring

@RequestBody : Annotation indicating a method parameter should be bound to the body of the HTTP request.

For example:

@RequestMapping(path = "/something", method = RequestMethod.PUT)
public void handle(@RequestBody String body, Writer writer) throws IOException {
    writer.write(body);
}

@ResponseBody annotation can be put on a method and indicates that the return type should be written straight to the HTTP response body (and not placed in a Model, or interpreted as a view name).

For example:

@RequestMapping(path = "/something", method = RequestMethod.PUT)
public  @ResponseBody String helloWorld() {
    return "Hello World";
}  

Alternatively, we can use @RestController annotation in place of @Controller annotation. This will remove the need to using @ResponseBody.

for more details

Entity Framework - Linq query with order by and group by

Your requirements are all over the place, but this is the solution to my understanding of them:

To group by Reference property:

var refGroupQuery = (from m in context.Measurements
            group m by m.Reference into refGroup
            select refGroup);

Now you say you want to limit results by "most recent numOfEntries" - I take this to mean you want to limit the returned Measurements... in that case:

var limitedQuery = from g in refGroupQuery
                   select new
                   {
                       Reference = g.Key,
                       RecentMeasurements = g.OrderByDescending( p => p.CreationTime ).Take( numOfEntries )
                   }

To order groups by first Measurement creation time (note you should order the measurements; if you want the earliest CreationTime value, substitue "g.SomeProperty" with "g.CreationTime"):

var refGroupsOrderedByFirstCreationTimeQuery = limitedQuery.OrderBy( lq => lq.RecentMeasurements.OrderBy( g => g.SomeProperty ).First().CreationTime );

To order groups by average CreationTime, use the Ticks property of the DateTime struct:

var refGroupsOrderedByAvgCreationTimeQuery = limitedQuery.OrderBy( lq => lq.RecentMeasurements.Average( g => g.CreationTime.Ticks ) );

Error: class X is public should be declared in a file named X.java

Name of public class must match the name of .java file in which it is placed (like public class Foo{} must be placed in Foo.java file). So either:

  • rename your file from Main.java to WeatherArray.java
  • rename the class from public class WeatherArray { to public class Main {

.bashrc: Permission denied

The .bashrc file is in your user home directory (~/.bashrc or ~vagrant/.bashrc both resolve to the same path), inside the VM's filesystem. This file is invisible on the host machine, so you can't use any Windows editors to edit it directly.

You have two simple choices:

  1. Learn how to use a console-based text editor. My favourite is vi (or vim), which takes 15 minutes to learn the basics and is much quicker for simple edits than anything else.

    vi .bashrc

  2. Copy .bashrc out to /vagrant (which is a shared directory) and edit it using your Windows editors. Make sure not to save it back with any extensions.

    cp .bashrc /vagrant ... edit using your host machine ... cp /vagrant/.bashrc .

I'd recommend getting to know the command-line based editors. Once you're working inside the VM, it's best to stay there as otherwise you might just get confused.

You (the vagrant user) are the owner of your home .bashrc so you do have permissions to edit it.

Once edited, you can execute it by typing source .bashrc I prefer to logout and in again (there may be more than one file executed on login).

Get user's non-truncated Active Directory groups from command line

Much easier way in PowerShell:

Get-ADPrincipalGroupMembership <username>

Requirement: the account you yourself are running under must be a member of the same domain as the target user, unless you specify -Credential and -Server (untested).

In addition, you must have the Active Directory Powershell module installed, which as @dave-lucre says in a comment to another answer, is not always an option.

For group names only, try one of these:

(Get-ADPrincipalGroupMembership <username>).Name
Get-ADPrincipalGroupMembership <username> |Select Name

Rotating a two-dimensional array in Python

I've had this problem myself and I've found the great wikipedia page on the subject (in "Common rotations" paragraph:
https://en.wikipedia.org/wiki/Rotation_matrix#Ambiguities

Then I wrote the following code, super verbose in order to have a clear understanding of what is going on.

I hope that you'll find it useful to dig more in the very beautiful and clever one-liner you've posted.

To quickly test it you can copy / paste it here:
http://www.codeskulptor.org/

triangle = [[0,0],[5,0],[5,2]]
coordinates_a = triangle[0]
coordinates_b = triangle[1]
coordinates_c = triangle[2]

def rotate90ccw(coordinates):
    print "Start coordinates:"
    print coordinates
    old_x = coordinates[0]
    old_y = coordinates[1]
# Here we apply the matrix coming from Wikipedia
# for 90 ccw it looks like:
# 0,-1
# 1,0
# What does this mean?
#
# Basically this is how the calculation of the new_x and new_y is happening:
# new_x = (0)(old_x)+(-1)(old_y)
# new_y = (1)(old_x)+(0)(old_y)
#
# If you check the lonely numbers between parenthesis the Wikipedia matrix's numbers
# finally start making sense.
# All the rest is standard formula, the same behaviour will apply to other rotations, just
# remember to use the other rotation matrix values available on Wiki for 180ccw and 170ccw
    new_x = -old_y
    new_y = old_x
    print "End coordinates:"
    print [new_x, new_y]

def rotate180ccw(coordinates):
    print "Start coordinates:"
    print coordinates
    old_x = coordinates[0]
    old_y = coordinates[1] 
    new_x = -old_x
    new_y = -old_y
    print "End coordinates:"
    print [new_x, new_y]

def rotate270ccw(coordinates):
    print "Start coordinates:"
    print coordinates
    old_x = coordinates[0]
    old_y = coordinates[1]  
    new_x = -old_x
    new_y = -old_y
    print "End coordinates:"
    print [new_x, new_y]

print "Let's rotate point A 90 degrees ccw:"
rotate90ccw(coordinates_a)
print "Let's rotate point B 90 degrees ccw:"
rotate90ccw(coordinates_b)
print "Let's rotate point C 90 degrees ccw:"
rotate90ccw(coordinates_c)
print "=== === === === === === === === === "
print "Let's rotate point A 180 degrees ccw:"
rotate180ccw(coordinates_a)
print "Let's rotate point B 180 degrees ccw:"
rotate180ccw(coordinates_b)
print "Let's rotate point C 180 degrees ccw:"
rotate180ccw(coordinates_c)
print "=== === === === === === === === === "
print "Let's rotate point A 270 degrees ccw:"
rotate270ccw(coordinates_a)
print "Let's rotate point B 270 degrees ccw:"
rotate270ccw(coordinates_b)
print "Let's rotate point C 270 degrees ccw:"
rotate270ccw(coordinates_c)
print "=== === === === === === === === === "

How to force 'cp' to overwrite directory instead of creating another one inside?

Try to use this composed of two steps command:

rm -rf bar && cp -r foo bar

Oracle Age calculation from Date of birth and Today

This seems considerably easier than what anyone else has suggested

select sysdate-to_date('30-jul-1977') from dual; 

Import XXX cannot be resolved for Java SE standard classes

This is an issue relating JRE.In my case (eclipse Luna with Maven plugin, JDK 7) I solved this by making following change in pom.xml and then Maven Update Project.

from:

 <configuration>
        <source>1.8</source>
        <target>1.8</target>
</configuration>

to:

 <configuration>
        <source>1.7</source>
        <target>1.7</target>
</configuration>

Screenshot showing problem in JRE: enter image description here

Is there a way to use SVG as content in a pseudo element :before or :after

<div class="author_">Lord Byron</div>

_x000D_
_x000D_
.author_ {  font-family: 'Playfair Display', serif; font-size: 1.25em; font-weight: 700;letter-spacing: 0.25em; font-style: italic;_x000D_
  position:relative;_x000D_
  margin-top: -0.5em;_x000D_
  color: black;_x000D_
  z-index:1;_x000D_
  overflow:hidden;_x000D_
  text-align:center;_x000D_
 _x000D_
}_x000D_
_x000D_
_x000D_
.author_:after{_x000D_
   left:20px;_x000D_
  margin:0 -100% 0 0;_x000D_
  display: inline-block;_x000D_
  height: 10px;_x000D_
  content: url(data:image/svg+xml,%0A%3Csvg%20xmlns%3D%22http%3A%2F%2Fwww.w3.org%2F2000%2Fsvg%22%20width%3D%22120px%22%20height%3D%2220px%22%20viewBox%3D%220%200%201200%20200%22%20xmlns%3Axlink%3D%22http%3A%2F%2Fwww.w3.org%2F1999%2Fxlink%22%3E%0A%20%20%3Cpath%20stroke%3D%22black%22%20stroke-width%3D%223%22%20fill%3D%22none%22%20d%3D%22M1145%2085c17%2C7%208%2C24%20-4%2C29%20-12%2C4%20-40%2C6%20-48%2C-8%20-9%2C-15%209%2C-34%2026%2C-42%2017%2C-7%2045%2C-6%2062%2C2%2017%2C9%2019%2C18%2020%2C27%201%2C9%200%2C29%20-27%2C52%20-28%2C23%20-52%2C34%20-102%2C33%20-49%2C0%20-130%2C-31%20-185%2C-50%20-56%2C-18%20-74%2C-21%20-96%2C-23%20-22%2C-2%20-29%2C-2%20-56%2C7%20-27%2C8%20-44%2C17%20-44%2C17%20-13%2C5%20-15%2C7%20-40%2C16%20-25%2C9%20-69%2C14%20-120%2C11%20-51%2C-3%20-126%2C-23%20-181%2C-32%20-54%2C-9%20-105%2C-20%20-148%2C-23%20-42%2C-3%20-71%2C1%20-104%2C5%20-34%2C5%20-65%2C15%20-98%2C22%22%2F%3E%0A%3C%2Fsvg%3E%0A);_x000D_
}_x000D_
.author_:before {_x000D_
  right:20px;_x000D_
  margin:0 0 0 -100%;_x000D_
  display: inline-block;_x000D_
  height: 10px;_x000D_
  content: url(data:image/svg+xml,%0A%3Csvg%20xmlns%3D%22http%3A%2F%2Fwww.w3.org%2F2000%2Fsvg%22%20width%3D%22120px%22%20height%3D%2220px%22%20viewBox%3D%220%200%201200%20130%22%20xmlns%3Axlink%3D%22http%3A%2F%2Fwww.w3.org%2F1999%2Fxlink%22%3E%0A%20%20%3Cpath%20stroke%3D%22black%22%20stroke-width%3D%223%22%20fill%3D%22none%22%20d%3D%22M55%2068c-17%2C6%20-8%2C23%204%2C28%2012%2C5%2040%2C7%2048%2C-8%209%2C-15%20-9%2C-34%20-26%2C-41%20-17%2C-8%20-45%2C-7%20-62%2C2%20-18%2C8%20-19%2C18%20-20%2C27%20-1%2C9%200%2C29%2027%2C52%2028%2C23%2052%2C33%20102%2C33%2049%2C-1%20130%2C-31%20185%2C-50%2056%2C-19%2074%2C-21%2096%2C-23%2022%2C-2%2029%2C-2%2056%2C6%2027%2C8%2043%2C17%2043%2C17%2014%2C6%2016%2C7%2041%2C16%2025%2C9%2069%2C15%20120%2C11%2051%2C-3%20126%2C-22%20181%2C-32%2054%2C-9%20105%2C-20%20148%2C-23%2042%2C-3%2071%2C1%20104%2C6%2034%2C4%2065%2C14%2098%2C22%22%2F%3E%0A%3C%2Fsvg%3E%0A);_x000D_
}
_x000D_
 <div class="author_">Lord Byron</div>
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Convenient tool for SVG encoding url-encoder

How to join a slice of strings into a single string?

Use a slice, not an arrray. Just create it using

reg := []string {"a","b","c"}

An alternative would have been to convert your array to a slice when joining :

fmt.Println(strings.Join(reg[:],","))

Read the Go blog about the differences between slices and arrays.

How to export html table to excel using javascript

This might be a better answer copied from this question. Please try it and give opinion here. Please vote up if found useful. Thank you.

<script type="text/javascript">
function generate_excel(tableid) {
  var table= document.getElementById(tableid);
  var html = table.outerHTML;
  window.open('data:application/vnd.ms-excel;base64,' + base64_encode(html));
}

function base64_encode (data) {
  // http://kevin.vanzonneveld.net
  // +   original by: Tyler Akins (http://rumkin.com)
  // +   improved by: Bayron Guevara
  // +   improved by: Thunder.m
  // +   improved by: Kevin van Zonneveld (http://kevin.vanzonneveld.net)
  // +   bugfixed by: Pellentesque Malesuada
  // +   improved by: Kevin van Zonneveld (http://kevin.vanzonneveld.net)
  // +   improved by: Rafal Kukawski (http://kukawski.pl)
  // *     example 1: base64_encode('Kevin van Zonneveld');
  // *     returns 1: 'S2V2aW4gdmFuIFpvbm5ldmVsZA=='
  // mozilla has this native
  // - but breaks in 2.0.0.12!
  //if (typeof this.window['btoa'] == 'function') {
  //    return btoa(data);
  //}
  var b64 = "ABCDEFGHIJKLMNOPQRSTUVWXYZabcdefghijklmnopqrstuvwxyz0123456789+/=";
  var o1, o2, o3, h1, h2, h3, h4, bits, i = 0,
    ac = 0,
    enc = "",
    tmp_arr = [];

  if (!data) {
    return data;
  }

  do { // pack three octets into four hexets
    o1 = data.charCodeAt(i++);
    o2 = data.charCodeAt(i++);
    o3 = data.charCodeAt(i++);

    bits = o1 << 16 | o2 << 8 | o3;

    h1 = bits >> 18 & 0x3f;
    h2 = bits >> 12 & 0x3f;
    h3 = bits >> 6 & 0x3f;
    h4 = bits & 0x3f;

    // use hexets to index into b64, and append result to encoded string
    tmp_arr[ac++] = b64.charAt(h1) + b64.charAt(h2) + b64.charAt(h3) + b64.charAt(h4);
  } while (i < data.length);

  enc = tmp_arr.join('');

  var r = data.length % 3;

  return (r ? enc.slice(0, r - 3) : enc) + '==='.slice(r || 3);

}
</script>

Docker compose, running containers in net:host

Those documents are outdated. I'm guessing the 1.6 in the URL is for Docker 1.6, not Compose 1.6. Check out the correct syntax here: https://docs.docker.com/compose/compose-file/#network_mode. You are looking for network_mode when using the v2 YAML format.

I need an unordered list without any bullets

 <div class="custom-control custom-checkbox left">
    <ul class="list-unstyled">
        <li>
         <label class="btn btn-secondary text-left" style="width:100%;text-align:left;padding:2px;">
           <input type="checkbox" style="zoom:1.7;vertical-align:bottom;" asp-for="@Model[i].IsChecked" class="custom-control-input" /> @Model[i].Title
         </label>
        </li>
     </ul>
</div>

Exporting functions from a DLL with dllexport

I think _naked might get what you want, but it also prevents the compiler from generating the stack management code for the function. extern "C" causes C style name decoration. Remove that and that should get rid of your _'s. The linker doesn't add the underscores, the compiler does. stdcall causes the argument stack size to be appended.

For more, see: http://en.wikipedia.org/wiki/X86_calling_conventions http://www.codeproject.com/KB/cpp/calling_conventions_demystified.aspx

The bigger question is why do you want to do that? What's wrong with the mangled names?

MySQL Error: #1142 - SELECT command denied to user

This error also arises for a syntax error occurred due to aliasing tablename.

For instance, when executed below query,

select * from a.table1, b.table2 where a.table1= b.table2

below error occurs:

MySQL Error: #1142. Response form the database. SELECT command denied to user "username@ip" for table "table1"

Solution : Syntax to alias tablename should be used proper, syntax solution for above instance >select * from table1 a, table2 b where a.table1= b.table2

How to store the hostname in a variable in a .bat file?

I usually read command output in to variables using the FOR command as it saves having to create temporary files. For example:

FOR /F "usebackq" %i IN (`hostname`) DO SET MYVAR=%i

Note, the above statement will work on the command line but not in a batch file. To use it in batch file escape the % in the FOR statement by putting them twice:

FOR /F "usebackq" %%i IN (`hostname`) DO SET MYVAR=%%i
ECHO %MYVAR%

There's a lot more you can do with FOR. For more details just type HELP FOR at command prompt.

How do I remove a comma off the end of a string?

This is a classic question, with two solutions. If you want to remove exactly one comma, which may or may not be there, use:

if (substr($string, -1, 1) == ',')
{
  $string = substr($string, 0, -1);
}

If you want to remove all commas from the end of a line use the simpler:

$string = rtrim($string, ',');

The rtrim function (and corresponding ltrim for left trim) is very useful as you can specify a range of characters to remove, i.e. to remove commas and trailing whitespace you would write:

$string = rtrim($string, ", \t\n");

Can I use return value of INSERT...RETURNING in another INSERT?

The best practice for this situation. Use RETURNING … INTO.

INSERT INTO teams VALUES (...) RETURNING id INTO last_id;

Note this is for PLPGSQL

how to display toolbox on the left side of window of Visual Studio Express for windows phone 7 development?

Ctrl-Alt-X is the keyboard shortcut I use, although that may because I have Resharper installed - otherwise Ctrl W, X.

From the menu: View -> Toolbox.

You can easily view/change key bindings using Tools -> Options Environment->Keyboard. It has a convenient UI where you can enter a word, and it shows you what key bindings include that word, including View.Toolbox.

You might want to browse through the online MSDN documentation on getting started with Visual Studio.

What is the difference between Cygwin and MinGW?

To use Cygwin in a commercial / proprietary / non-open-source application, you'll need to fork out tens of thousands of dollars for a "license buyout" from Red Hat; this invalidates the standard licensing terms at a considerable cost. Google "cygwin license cost" and see first few results.

For mingw, no such cost is incurred, and the licenses (PD, BSD, MIT) are extremely permissive. At most you may be expected to supply license details with your application, such as the winpthreads license required when using mingw64-tdm.

EDIT thanks to Izzy Helianthus: The commercial license is no longer available or necessary because the API library found in the winsup subdirectory of Cygwin is now being distributed under the LGPL, as opposed to the full GPL.

Extract a subset of a dataframe based on a condition involving a field

Here are the two main approaches. I prefer this one for its readability:

bar <- subset(foo, location == "there")

Note that you can string together many conditionals with & and | to create complex subsets.

The second is the indexing approach. You can index rows in R with either numeric, or boolean slices. foo$location == "there" returns a vector of T and F values that is the same length as the rows of foo. You can do this to return only rows where the condition returns true.

foo[foo$location == "there", ]

"unadd" a file to svn before commit

Full process (Unix svn package):

Check files are not in SVN:

> svn st -u folder 
? folder

Add all (including ignored files):

> svn add folder
A   folder
A   folder/file1.txt
A   folder/folder2
A   folder/folder2/file2.txt
A   folder/folderToIgnore
A   folder/folderToIgnore/fileToIgnore1.txt
A   fileToIgnore2.txt

Remove "Add" Flag to All * Ignore * files:

> cd folder

> svn revert --recursive folderToIgnore
Reverted 'folderToIgnore'
Reverted 'folderToIgnore/fileToIgnore1.txt'


> svn revert fileToIgnore2.txt
Reverted 'fileToIgnore2.txt'

Edit svn ignore on folder

svn propedit svn:ignore .

Add two singles lines with just the following:

folderToIgnore
fileToIgnore2.txt

Check which files will be upload and commit:

> cd ..

> svn st -u
A   folder
A   folder/file1.txt
A   folder/folder2
A   folder/folder2/file2.txt


> svn ci -m "Commit message here"

Can I convert a C# string value to an escaped string literal

There's a method for this in Roslyn's Microsoft.CodeAnalysis.CSharp package on nuget :

    private static string ToLiteral(string valueTextForCompiler)
    {
        return Microsoft.CodeAnalysis.CSharp.SymbolDisplay.FormatLiteral(valueTextForCompiler, false);
    }

Obviously this didn't exist at the time of the original question, but might help people who end up here from Google.

How do you update a DateTime field in T-SQL?

When in doubt, be explicit about the data type conversion using CAST/CONVERT:

UPDATE TABLE
   SET EndDate = CAST('2009-05-25' AS DATETIME)
 WHERE Id = 1

How do I use the nohup command without getting nohup.out?

The nohup command only writes to nohup.out if the output would otherwise go to the terminal. If you have redirected the output of the command somewhere else - including /dev/null - that's where it goes instead.

 nohup command >/dev/null 2>&1   # doesn't create nohup.out

If you're using nohup, that probably means you want to run the command in the background by putting another & on the end of the whole thing:

 nohup command >/dev/null 2>&1 & # runs in background, still doesn't create nohup.out

On Linux, running a job with nohup automatically closes its input as well. On other systems, notably BSD and macOS, that is not the case, so when running in the background, you might want to close input manually. While closing input has no effect on the creation or not of nohup.out, it avoids another problem: if a background process tries to read anything from standard input, it will pause, waiting for you to bring it back to the foreground and type something. So the extra-safe version looks like this:

nohup command </dev/null >/dev/null 2>&1 & # completely detached from terminal 

Note, however, that this does not prevent the command from accessing the terminal directly, nor does it remove it from your shell's process group. If you want to do the latter, and you are running bash, ksh, or zsh, you can do so by running disown with no argument as the next command. That will mean the background process is no longer associated with a shell "job" and will not have any signals forwarded to it from the shell. (Note the distinction: a disowned process gets no signals forwarded to it automatically by its parent shell - but without nohup, it will still receive a HUP signal sent via other means, such as a manual kill command. A nohup'ed process ignores any and all HUP signals, no matter how they are sent.)

Explanation:

In Unixy systems, every source of input or target of output has a number associated with it called a "file descriptor", or "fd" for short. Every running program ("process") has its own set of these, and when a new process starts up it has three of them already open: "standard input", which is fd 0, is open for the process to read from, while "standard output" (fd 1) and "standard error" (fd 2) are open for it to write to. If you just run a command in a terminal window, then by default, anything you type goes to its standard input, while both its standard output and standard error get sent to that window.

But you can ask the shell to change where any or all of those file descriptors point before launching the command; that's what the redirection (<, <<, >, >>) and pipe (|) operators do.

The pipe is the simplest of these... command1 | command2 arranges for the standard output of command1 to feed directly into the standard input of command2. This is a very handy arrangement that has led to a particular design pattern in UNIX tools (and explains the existence of standard error, which allows a program to send messages to the user even though its output is going into the next program in the pipeline). But you can only pipe standard output to standard input; you can't send any other file descriptors to a pipe without some juggling.

The redirection operators are friendlier in that they let you specify which file descriptor to redirect. So 0<infile reads standard input from the file named infile, while 2>>logfile appends standard error to the end of the file named logfile. If you don't specify a number, then input redirection defaults to fd 0 (< is the same as 0<), while output redirection defaults to fd 1 (> is the same as 1>).

Also, you can combine file descriptors together: 2>&1 means "send standard error wherever standard output is going". That means that you get a single stream of output that includes both standard out and standard error intermixed with no way to separate them anymore, but it also means that you can include standard error in a pipe.

So the sequence >/dev/null 2>&1 means "send standard output to /dev/null" (which is a special device that just throws away whatever you write to it) "and then send standard error to wherever standard output is going" (which we just made sure was /dev/null). Basically, "throw away whatever this command writes to either file descriptor".

When nohup detects that neither its standard error nor output is attached to a terminal, it doesn't bother to create nohup.out, but assumes that the output is already redirected where the user wants it to go.

The /dev/null device works for input, too; if you run a command with </dev/null, then any attempt by that command to read from standard input will instantly encounter end-of-file. Note that the merge syntax won't have the same effect here; it only works to point a file descriptor to another one that's open in the same direction (input or output). The shell will let you do >/dev/null <&1, but that winds up creating a process with an input file descriptor open on an output stream, so instead of just hitting end-of-file, any read attempt will trigger a fatal "invalid file descriptor" error.

Error LNK2019: Unresolved External Symbol in Visual Studio

When you have everything #included, an unresolved external symbol is often a missing * or & in the declaration or definition of a function.

How to change the URL from "localhost" to something else, on a local system using wampserver?

After another hour or two I can actually answer my own question.

Someone on another forum mentioned that you need to keep a mention of plain ol' localhost in the httpd-vhost.conf file, so here's what I ended up with in there:

ServerName localhost

DocumentRoot "c:/wamp/www/"

DocumentRoot "C:/wamp/www/pocket/"
ServerName pocket.clickng.com
ServerAlias pocket.clickng.com
ErrorLog "logs/pocket.clickng.com-error.log"
CustomLog "logs/pocket.clickng.com-access.log" common
<Directory "C:/wamp/www/pocket/">
    Options Indexes FollowSymLinks Includes
    AllowOverride All
    Order allow,deny
    Allow from all
</Directory>

Exit WAMP, restart - good to go. Hope this helps someone else :)

Open new Terminal Tab from command line (Mac OS X)

With X installed (e.g. from homebrew, or Quartz), a simple "xterm &" does (nearly) the trick, it opens a new terminal window (not a tab, though).

Deprecated meaning?

Deprecated means they don't recommend using it, and that it isn't undergoing further development. But it should not work differently than it did in a previous version unless documentation explicitly states that.

  1. Yes, otherwise it wouldn't be called "deprecated"

  2. Unless stated otherwise in docs, it should be the same as before

  3. No, but if there were problems in v1 they aren't about to fix them

Show div when radio button selected

Input elements should have value attributes. Add them and use this:

$("input[name='test']").click(function () {
    $('#show-me').css('display', ($(this).val() === 'a') ? 'block':'none');
});

jsFiddle example

How to execute Python scripts in Windows?

Simply run the command:

C:>python .\file_name.py

Assuming the file name is within same folder and Python has already been added to environment variables.

What JSON library to use in Scala?

Unfortunately writing a JSON library is the Scala community's version of coding a todo list app.

There are quite a variety of alternatives. I list them in no particular order, with notes:

  1. parsing.json.JSON - Warning this library is available only up to Scala version 2.9.x (removed in newer versions)
  2. spray-json - Extracted from the Spray project
  3. Jerkson ± - Warning a nice library (built on top of Java Jackson) but now abandonware. If you are going to use this, probably follow the Scalding project's example and use the backchat.io fork
  4. sjson - By Debasish Ghosh
  5. lift-json - Can be used separately from the Lift project
  6. json4s § ± - An extraction from lift-json, which is attempting to create a standard JSON AST which other JSON libraries can use. Includes a Jackson-backed implementation
  7. Argonaut § - A FP-oriented JSON library for Scala, from the people behind Scalaz
  8. play-json ± - Now available standalone, see this answer for details
  9. dijon - A handy, safe and efficient JSON library, uses jsoniter-scala under hood.
  10. sonofjson - JSON library aiming for a super-simple API
  11. Jawn - JSON library by Erik Osheim aiming for Jackson-or-faster speed
  12. Rapture JSON ± - a JSON front-end which can use 2, 4, 5, 6, 7, 11 or Jackson as back-ends
  13. circe - fork of Argonaut built on top of cats instead of scalaz
  14. jsoniter-scala - Scala macros for compile-time generation of ultra-fast JSON codecs
  15. jackson-module-scala - Add-on module for Jackson to support Scala-specific datatypes
  16. borer - Efficient CBOR and JSON (de)serialization in Scala

= has not fixed security vulnerabilities, § = has Scalaz integration, ± = supports interop with Jackson JsonNode

In Snowplow we use json4s with the Jackson back-end; we've had good experiences with Argonaut too.

How to insert a SQLite record with a datetime set to 'now' in Android application?

In my code I use DATETIME DEFAULT CURRENT_TIMESTAMP as the type and constraint of the column.

In your case your table definition would be

create table notes (
  _id integer primary key autoincrement, 
  created_date date default CURRENT_DATE
)

Selenium IDE - Command to wait for 5 seconds

Use the pause command and enter the number of milliseconds in the Target field.

Set speed to fastest (Actions --> Fastest), otherwise it won't work.

How to loop over grouped Pandas dataframe?

df.groupby('l_customer_id_i').agg(lambda x: ','.join(x)) does already return a dataframe, so you cannot loop over the groups anymore.

In general:

  • df.groupby(...) returns a GroupBy object (a DataFrameGroupBy or SeriesGroupBy), and with this, you can iterate through the groups (as explained in the docs here). You can do something like:

    grouped = df.groupby('A')
    
    for name, group in grouped:
        ...
    
  • When you apply a function on the groupby, in your example df.groupby(...).agg(...) (but this can also be transform, apply, mean, ...), you combine the result of applying the function to the different groups together in one dataframe (the apply and combine step of the 'split-apply-combine' paradigm of groupby). So the result of this will always be again a DataFrame (or a Series depending on the applied function).

How do I check which version of NumPy I'm using?

Simply

pip show numpy

and for pip3

pip3 show numpy

Works on both windows and linux. Should work on mac too if you are using pip.

How to define static constant in a class in swift

Adding to @Martin's answer...

If anyone planning to keep an application level constant file, you can group the constant based on their type or nature

struct Constants {
    struct MixpanelConstants {
        static let activeScreen = "Active Screen";
    }
    struct CrashlyticsConstants {
        static let userType = "User Type";
    }
}

Call : Constants.MixpanelConstants.activeScreen

UPDATE 5/5/2019 (kinda off topic but ???)

After reading some code guidelines & from personal experiences it seems structs are not the best approach for storing global constants for a couple of reasons. Especially the above code doesn't prevent initialization of the struct. We can achieve it by adding some boilerplate code but there is a better approach

ENUMS

The same can be achieved using an enum with a more secure & clear representation

enum Constants {
    enum MixpanelConstants: String {
        case activeScreen = "Active Screen";
    }
    enum CrashlyticsConstants: String {
        case userType = "User Type";
    }
}

print(Constants.MixpanelConstants.activeScreen.rawValue)

Why extend the Android Application class?

The Application class is a singleton that you can access from any activity or anywhere else you have a Context object.

You also get a little bit of lifecycle.

You could use the Application's onCreate method to instantiate expensive, but frequently used objects like an analytics helper. Then you can access and use those objects everywhere.

The Definitive C Book Guide and List

Beginner

Introductory, no previous programming experience

  • C++ Primer * (Stanley Lippman, Josée Lajoie, and Barbara E. Moo) (updated for C++11) Coming at 1k pages, this is a very thorough introduction into C++ that covers just about everything in the language in a very accessible format and in great detail. The fifth edition (released August 16, 2012) covers C++11. [Review]

    * Not to be confused with C++ Primer Plus (Stephen Prata), with a significantly less favorable review.

  • Programming: Principles and Practice Using C++ (Bjarne Stroustrup, 2nd Edition - May 25, 2014) (updated for C++11/C++14) An introduction to programming using C++ by the creator of the language. A good read, that assumes no previous programming experience, but is not only for beginners.

Introductory, with previous programming experience

  • A Tour of C++ (Bjarne Stroustrup) (2nd edition for C++17) The “tour” is a quick (about 180 pages and 14 chapters) tutorial overview of all of standard C++ (language and standard library, and using C++11) at a moderately high level for people who already know C++ or at least are experienced programmers. This book is an extended version of the material that constitutes Chapters 2-5 of The C++ Programming Language, 4th edition.

  • Accelerated C++ (Andrew Koenig and Barbara Moo, 1st Edition - August 24, 2000) This basically covers the same ground as the C++ Primer, but does so on a fourth of its space. This is largely because it does not attempt to be an introduction to programming, but an introduction to C++ for people who've previously programmed in some other language. It has a steeper learning curve, but, for those who can cope with this, it is a very compact introduction to the language. (Historically, it broke new ground by being the first beginner's book to use a modern approach to teaching the language.) Despite this, the C++ it teaches is purely C++98. [Review]

Best practices

  • Effective C++ (Scott Meyers, 3rd Edition - May 22, 2005) This was written with the aim of being the best second book C++ programmers should read, and it succeeded. Earlier editions were aimed at programmers coming from C, the third edition changes this and targets programmers coming from languages like Java. It presents ~50 easy-to-remember rules of thumb along with their rationale in a very accessible (and enjoyable) style. For C++11 and C++14 the examples and a few issues are outdated and Effective Modern C++ should be preferred. [Review]

  • Effective Modern C++ (Scott Meyers) This is basically the new version of Effective C++, aimed at C++ programmers making the transition from C++03 to C++11 and C++14.

  • Effective STL (Scott Meyers) This aims to do the same to the part of the standard library coming from the STL what Effective C++ did to the language as a whole: It presents rules of thumb along with their rationale. [Review]


Intermediate

  • More Effective C++ (Scott Meyers) Even more rules of thumb than Effective C++. Not as important as the ones in the first book, but still good to know.

  • Exceptional C++ (Herb Sutter) Presented as a set of puzzles, this has one of the best and thorough discussions of the proper resource management and exception safety in C++ through Resource Acquisition is Initialization (RAII) in addition to in-depth coverage of a variety of other topics including the pimpl idiom, name lookup, good class design, and the C++ memory model. [Review]

  • More Exceptional C++ (Herb Sutter) Covers additional exception safety topics not covered in Exceptional C++, in addition to discussion of effective object-oriented programming in C++ and correct use of the STL. [Review]

  • Exceptional C++ Style (Herb Sutter) Discusses generic programming, optimization, and resource management; this book also has an excellent exposition of how to write modular code in C++ by using non-member functions and the single responsibility principle. [Review]

  • C++ Coding Standards (Herb Sutter and Andrei Alexandrescu) “Coding standards” here doesn't mean “how many spaces should I indent my code?” This book contains 101 best practices, idioms, and common pitfalls that can help you to write correct, understandable, and efficient C++ code. [Review]

  • C++ Templates: The Complete Guide (David Vandevoorde and Nicolai M. Josuttis) This is the book about templates as they existed before C++11. It covers everything from the very basics to some of the most advanced template metaprogramming and explains every detail of how templates work (both conceptually and at how they are implemented) and discusses many common pitfalls. Has excellent summaries of the One Definition Rule (ODR) and overload resolution in the appendices. A second edition covering C++11, C++14 and C++17 has been already published. [Review]

  • C++ 17 - The Complete Guide (Nicolai M. Josuttis) This book describes all the new features introduced in the C++17 Standard covering everything from the simple ones like 'Inline Variables', 'constexpr if' all the way up to 'Polymorphic Memory Resources' and 'New and Delete with overaligned Data'. [Review]

  • C++ in Action (Bartosz Milewski). This book explains C++ and its features by building an application from ground up. [Review]

  • Functional Programming in C++ (Ivan Cukic). This book introduces functional programming techniques to modern C++ (C++11 and later). A very nice read for those who want to apply functional programming paradigms to C++.

  • Professional C++ (Marc Gregoire, 5th Edition - Feb 2021) Provides a comprehensive and detailed tour of the C++ language implementation replete with professional tips and concise but informative in-text examples, emphasizing C++20 features. Uses C++20 features, such as modules and std::format throughout all examples.


Advanced

  • Modern C++ Design (Andrei Alexandrescu) A groundbreaking book on advanced generic programming techniques. Introduces policy-based design, type lists, and fundamental generic programming idioms then explains how many useful design patterns (including small object allocators, functors, factories, visitors, and multi-methods) can be implemented efficiently, modularly, and cleanly using generic programming. [Review]

  • C++ Template Metaprogramming (David Abrahams and Aleksey Gurtovoy)

  • C++ Concurrency In Action (Anthony Williams) A book covering C++11 concurrency support including the thread library, the atomics library, the C++ memory model, locks and mutexes, as well as issues of designing and debugging multithreaded applications. A second edition covering C++14 and C++17 has been already published. [Review]

  • Advanced C++ Metaprogramming (Davide Di Gennaro) A pre-C++11 manual of TMP techniques, focused more on practice than theory. There are a ton of snippets in this book, some of which are made obsolete by type traits, but the techniques, are nonetheless useful to know. If you can put up with the quirky formatting/editing, it is easier to read than Alexandrescu, and arguably, more rewarding. For more experienced developers, there is a good chance that you may pick up something about a dark corner of C++ (a quirk) that usually only comes about through extensive experience.


Reference Style - All Levels

  • The C++ Programming Language (Bjarne Stroustrup) (updated for C++11) The classic introduction to C++ by its creator. Written to parallel the classic K&R, this indeed reads very much like it and covers just about everything from the core language to the standard library, to programming paradigms to the language's philosophy. [Review] Note: All releases of the C++ standard are tracked in the question "Where do I find the current C or C++ standard documents?".

  • C++ Standard Library Tutorial and Reference (Nicolai Josuttis) (updated for C++11) The introduction and reference for the C++ Standard Library. The second edition (released on April 9, 2012) covers C++11. [Review]

  • The C++ IO Streams and Locales (Angelika Langer and Klaus Kreft) There's very little to say about this book except that, if you want to know anything about streams and locales, then this is the one place to find definitive answers. [Review]

C++11/14/17/… References:

  • The C++11/14/17 Standard (INCITS/ISO/IEC 14882:2011/2014/2017) This, of course, is the final arbiter of all that is or isn't C++. Be aware, however, that it is intended purely as a reference for experienced users willing to devote considerable time and effort to its understanding. The C++17 standard is released in electronic form for 198 Swiss Francs.

  • The C++17 standard is available, but seemingly not in an economical form – directly from the ISO it costs 198 Swiss Francs (about $200 US). For most people, the final draft before standardization is more than adequate (and free). Many will prefer an even newer draft, documenting new features that are likely to be included in C++20.

  • Overview of the New C++ (C++11/14) (PDF only) (Scott Meyers) (updated for C++14) These are the presentation materials (slides and some lecture notes) of a three-day training course offered by Scott Meyers, who's a highly respected author on C++. Even though the list of items is short, the quality is high.

  • The C++ Core Guidelines (C++11/14/17/…) (edited by Bjarne Stroustrup and Herb Sutter) is an evolving online document consisting of a set of guidelines for using modern C++ well. The guidelines are focused on relatively higher-level issues, such as interfaces, resource management, memory management and concurrency affecting application architecture and library design. The project was announced at CppCon'15 by Bjarne Stroustrup and others and welcomes contributions from the community. Most guidelines are supplemented with a rationale and examples as well as discussions of possible tool support. Many rules are designed specifically to be automatically checkable by static analysis tools.

  • The C++ Super-FAQ (Marshall Cline, Bjarne Stroustrup and others) is an effort by the Standard C++ Foundation to unify the C++ FAQs previously maintained individually by Marshall Cline and Bjarne Stroustrup and also incorporating new contributions. The items mostly address issues at an intermediate level and are often written with a humorous tone. Not all items might be fully up to date with the latest edition of the C++ standard yet.

  • cppreference.com (C++03/11/14/17/…) (initiated by Nate Kohl) is a wiki that summarizes the basic core-language features and has extensive documentation of the C++ standard library. The documentation is very precise but is easier to read than the official standard document and provides better navigation due to its wiki nature. The project documents all versions of the C++ standard and the site allows filtering the display for a specific version. The project was presented by Nate Kohl at CppCon'14.


Classics / Older

Note: Some information contained within these books may not be up-to-date or no longer considered best practice.

  • The Design and Evolution of C++ (Bjarne Stroustrup) If you want to know why the language is the way it is, this book is where you find answers. This covers everything before the standardization of C++.

  • Ruminations on C++ - (Andrew Koenig and Barbara Moo) [Review]

  • Advanced C++ Programming Styles and Idioms (James Coplien) A predecessor of the pattern movement, it describes many C++-specific “idioms”. It's certainly a very good book and might still be worth a read if you can spare the time, but quite old and not up-to-date with current C++.

  • Large Scale C++ Software Design (John Lakos) Lakos explains techniques to manage very big C++ software projects. Certainly, a good read, if it only was up to date. It was written long before C++ 98 and misses on many features (e.g. namespaces) important for large-scale projects. If you need to work in a big C++ software project, you might want to read it, although you need to take more than a grain of salt with it. The first volume of a new edition is released in 2019.

  • Inside the C++ Object Model (Stanley Lippman) If you want to know how virtual member functions are commonly implemented and how base objects are commonly laid out in memory in a multi-inheritance scenario, and how all this affects performance, this is where you will find thorough discussions of such topics.

  • The Annotated C++ Reference Manual (Bjarne Stroustrup, Margaret A. Ellis) This book is quite outdated in the fact that it explores the 1989 C++ 2.0 version - Templates, exceptions, namespaces and new casts were not yet introduced. Saying that however, this book goes through the entire C++ standard of the time explaining the rationale, the possible implementations, and features of the language. This is not a book to learn programming principles and patterns on C++, but to understand every aspect of the C++ language.

  • Thinking in C++ (Bruce Eckel, 2nd Edition, 2000). Two volumes; is a tutorial style free set of intro level books. Downloads: vol 1, vol 2. Unfortunately they're marred by a number of trivial errors (e.g. maintaining that temporaries are automatically const), with no official errata list. A partial 3rd party errata list is available at http://www.computersciencelab.com/Eckel.htm, but it is apparently not maintained.

  • Scientific and Engineering C++: An Introduction to Advanced Techniques and Examples (John Barton and Lee Nackman) It is a comprehensive and very detailed book that tried to explain and make use of all the features available in C++, in the context of numerical methods. It introduced at the time several new techniques, such as the Curiously Recurring Template Pattern (CRTP, also called Barton-Nackman trick). It pioneered several techniques such as dimensional analysis and automatic differentiation. It came with a lot of compilable and useful code, ranging from an expression parser to a Lapack wrapper. The code is still available online. Unfortunately, the books have become somewhat outdated in the style and C++ features, however, it was an incredible tour-de-force at the time (1994, pre-STL). The chapters on dynamics inheritance are a bit complicated to understand and not very useful. An updated version of this classic book that includes move semantics and the lessons learned from the STL would be very nice.

Docker: How to use bash with an Alpine based docker image?

Try using RUN /bin/sh instead of bash.

Regex in JavaScript for validating decimal numbers

The schema for passing the value in as a string. The regex will validate a string of at least one digit, possibly followed by a period and exactly two digits:

{
    "type": "string",
    "pattern": "^[0-9]+(\\.[0-9]{2})?$"
}

The schema below is equivalent, except that it also allows empty strings:

{
    "type": "string",
    "pattern": "^$|^[0-9]+(\\.[0-9]{2})?$"
}

Add target="_blank" in CSS

While waiting for the adoption of CSS3 targeting…

While waiting for the adoption of CSS3 targeting by the major browsers, one could run the following sed command once the (X)HTML has been created:

sed -i 's|href="http|target="_blank" href="http|g' index.html

It will add target="_blank" to all external hyperlinks. Variations are also possible.

EDIT

I use this at the end of the makefile which generates every web page on my site.

jQuery/JavaScript to replace broken images

You can use GitHub's own fetch for this:

Frontend: https://github.com/github/fetch
or for Backend, a Node.js version: https://github.com/bitinn/node-fetch

fetch(url)
  .then(function(res) {
    if (res.status == '200') {
      return image;
    } else {
      return placeholder;
    }
  }

Edit: This method is going to replace XHR and supposedly already has been in Chrome. To anyone reading this in the future, you may not need the aforementioned library included.

CLEAR SCREEN - Oracle SQL Developer shortcut?

Use cl scr on the Sql* command line tool to clear all the matter on the screen.

Remove a file from the list that will be committed

if you have already pushed your commit then. do

git checkout origin/<remote-branch> <filename>
git commit --amend

AND If you have not pushed the changes on the server you can use

git reset --soft HEAD~1

jQuery table sort

This one does not hang up the browser/s, easy configurable further:

var table = $('table');

$('th.sortable').click(function(){
    var table = $(this).parents('table').eq(0);
    var ths = table.find('tr:gt(0)').toArray().sort(compare($(this).index()));
    this.asc = !this.asc;
    if (!this.asc)
       ths = ths.reverse();
    for (var i = 0; i < ths.length; i++)
       table.append(ths[i]);
});

function compare(idx) {
    return function(a, b) {
       var A = tableCell(a, idx), B = tableCell(b, idx)
       return $.isNumeric(A) && $.isNumeric(B) ? 
          A - B : A.toString().localeCompare(B)
    }
}

function tableCell(tr, index){ 
    return $(tr).children('td').eq(index).text() 
}

How do I access an access array item by index in handlebars?

In my case I wanted to access an array inside a custom helper like so,

{{#ifCond arr.[@index] "foo" }}

Which did not work, but the answer suggested by @julesbou worked.

Working code:

{{#ifCond (lookup arr @index) "" }}

Hope this helps! Cheers.

Extension gd is missing from your system - laravel composer Update

Using Manjaro(Arch) Linux:

$ sudo pacman -S php-gd

In file /etc/php/php-ini, add the line:

extension=gd.so

Recommended Fonts for Programming?

I have been using the Dina - http://www.donationcoder.com/Software/Jibz/Dina/index.html - font for awhile now for text editing and it seems to be doing the job nicely.

What is the default root pasword for MySQL 5.7

In my case the data directory was automatically initialized with the --initialize-insecure option. So /var/log/mysql/error.log does not contain a temporary password but:

[Warning] root@localhost is created with an empty password ! Please consider switching off the --initialize-insecure option.

What worked was:

shell> mysql -u root --skip-password
mysql> ALTER USER 'root'@'localhost' IDENTIFIED BY 'new_password';

Details: MySQL 5.7 Reference Manual > 2.10.4 Securing the Initial MySQL Account

How to fix C++ error: expected unqualified-id

Get rid of the semicolon after WordGame.

You really should have discovered this problem when the class was a lot smaller. When you're writing code, you should be compiling about every time you add half a dozen lines.

C# Create New T()

Since this is tagged C# 4. With the open sourece framework ImpromptuIntereface it will use the dlr to call the constructor it is significantly faster than Activator when your constructor has arguments, and negligibly slower when it doesn't. However the main advantage is that it will handle constructors with C# 4.0 optional parameters correctly, something that Activator won't do.

protected T GetObject(params object[] args)
{
    return (T)Impromptu.InvokeConstructor(typeof(T), args);
}

Using ffmpeg to change framerate

You can use this command and the video duration is still unaltered.

ffmpeg -i input.mp4 -r 24 output.mp4

How to search for occurrences of more than one space between words in a line

[ ]{2,}

SPACE (2 or more)

You could also check that before and after those spaces words follow. (not other whitespace like tabs or new lines)

\w[ ]{2,}\w

the same, but you can also pick (capture) only the spaces for tasks like replacement

\w([ ]{2,})\w

or see that before and after spaces there is anything, not only word characters (except whitespace)

[^\s]([ ]{2,})[^\s]

Hiding the address bar of a browser (popup)

You could make the webpage scroll down to a position where you can't see the address bar, and if the user scrolls, the page should return to your set position. In that way, Mobile browsers when scrolled down , will try to guve you full-screen experience. So it will hide the address bar. I don't know the code, someone else might put up the code.

XAMPP on Windows - Apache not starting

For me, the problem was I had two installations of Apache Tomcat

The following steps solved my problem:

  1. Open up services.msc in command prompt
  2. Select the Apache Tomcat service, right click and select properties
  3. Check the path to the executable of the service
  4. Follow the instructions in https://stackoverflow.com/questions/7190480/modifying-the-path-to-executable-of-a-windows-service to change the path to "\tomcat\bin\tomcat7.exe" //RS//Tomcat7
  5. Restart XAMPP Control Panel

Filtering a data frame by values in a column

Thought I'd update this with a dplyr solution

library(dplyr)    
filter(studentdata, Drink == "water")

C++ cout hex values?

std::hex is defined in <ios> which is included by <iostream>. But to use things like std::setprecision/std::setw/std::setfill/etc you have to include <iomanip>.

How to read file binary in C#?

You can use BinaryReader to read each of the bytes, then use BitConverter.ToString(byte[]) to find out how each is represented in binary.

You can then use this representation and write it to a file.

Sys.WebForms.PageRequestManagerServerErrorException: An unknown error occurred while processing the request on the server."

This solution is helpful too:

Add validateRequest="false" in the <%@ Page directive.

This is because ASP.net examines input from the browser for dangerous values. More info in this link

How to position one element relative to another with jQuery?

Why complicating too much? Solution is very simple

css:

.active-div{
position:relative;
}

.menu-div{
position:absolute;
top:0;
right:0;
display:none;
}

jquery:

$(function(){
    $(".active-div").hover(function(){
    $(".menu-div").prependTo(".active-div").show();
    },function(){$(".menu-div").hide();
})

It works even if,

  • Two divs placed anywhere else
  • Browser Re-sized

How to set child process' environment variable in Makefile

As MadScientist pointed out, you can export individual variables with:

export MY_VAR = foo  # Available for all targets

Or export variables for a specific target (target-specific variables):

my-target: export MY_VAR_1 = foo
my-target: export MY_VAR_2 = bar
my-target: export MY_VAR_3 = baz

my-target: dependency_1 dependency_2
  echo do something

You can also specify the .EXPORT_ALL_VARIABLES target to—you guessed it!—EXPORT ALL THE THINGS!!!:

.EXPORT_ALL_VARIABLES:

MY_VAR_1 = foo
MY_VAR_2 = bar
MY_VAR_3 = baz

test:
  @echo $$MY_VAR_1 $$MY_VAR_2 $$MY_VAR_3

see .EXPORT_ALL_VARIABLES

How to check if android checkbox is checked within its onClick method (declared in XML)?

You can try this code:

public void itemClicked(View v) {
 //code to check if this checkbox is checked!
 if(((Checkbox)v).isChecked()){
   // code inside if
 }
}

Spring: How to inject a value to static field?

First of all, public static non-final fields are evil. Spring does not allow injecting to such fields for a reason.

Your workaround is valid, you don't even need getter/setter, private field is enough. On the other hand try this:

@Value("${my.name}")
public void setPrivateName(String privateName) {
    Sample.name = privateName;
}  

(works with @Autowired/@Resource). But to give you some constructive advice: Create a second class with private field and getter instead of public static field.

Is there a Python Library that contains a list of all the ascii characters?

Since ASCII printable characters are a pretty small list (bytes with values between 32 and 127), it's easy enough to generate when you need:

>>> for c in (chr(i) for i in range(32,127)):
...     print c
... 

!
"
#
$
%
... # a few lines removed :)
y
z
{
|
}
~

AngularJS - How to use $routeParams in generating the templateUrl?

I was having a similar issue and used $stateParams instead of routeParam

How can I get current location from user in iOS

Try this Simple Steps....

NOTE: Please check device location latitude & logitude if you are using simulator means. By defaults its none only.

Step 1: Import CoreLocation framework in .h File

#import <CoreLocation/CoreLocation.h>

Step 2: Add delegate CLLocationManagerDelegate

@interface yourViewController : UIViewController<CLLocationManagerDelegate>
{
    CLLocationManager *locationManager;
    CLLocation *currentLocation;
}

Step 3: Add this code in class file

- (void)viewDidLoad
{
    [super viewDidLoad];
    [self CurrentLocationIdentifier]; // call this method
}

Step 4: Method to detect current location

//------------ Current Location Address-----
-(void)CurrentLocationIdentifier
{
    //---- For getting current gps location
    locationManager = [CLLocationManager new];
    locationManager.delegate = self;
    locationManager.distanceFilter = kCLDistanceFilterNone;
    locationManager.desiredAccuracy = kCLLocationAccuracyBest;
    [locationManager startUpdatingLocation];
    //------
}

Step 5: Get location using this method

- (void)locationManager:(CLLocationManager *)manager didUpdateLocations:(NSArray *)locations
{
    currentLocation = [locations objectAtIndex:0];
    [locationManager stopUpdatingLocation];
    CLGeocoder *geocoder = [[CLGeocoder alloc] init] ;
    [geocoder reverseGeocodeLocation:currentLocation completionHandler:^(NSArray *placemarks, NSError *error)
     {
         if (!(error))
         {
             CLPlacemark *placemark = [placemarks objectAtIndex:0];
             NSLog(@"\nCurrent Location Detected\n");
             NSLog(@"placemark %@",placemark);
             NSString *locatedAt = [[placemark.addressDictionary valueForKey:@"FormattedAddressLines"] componentsJoinedByString:@", "];
             NSString *Address = [[NSString alloc]initWithString:locatedAt];
             NSString *Area = [[NSString alloc]initWithString:placemark.locality];
             NSString *Country = [[NSString alloc]initWithString:placemark.country];
             NSString *CountryArea = [NSString stringWithFormat:@"%@, %@", Area,Country];
             NSLog(@"%@",CountryArea);
         }
         else
         {
             NSLog(@"Geocode failed with error %@", error);
             NSLog(@"\nCurrent Location Not Detected\n");
             //return;
             CountryArea = NULL;
         }
         /*---- For more results 
         placemark.region);
         placemark.country);
         placemark.locality); 
         placemark.name);
         placemark.ocean);
         placemark.postalCode);
         placemark.subLocality);
         placemark.location);
          ------*/
     }];
}

adding onclick event to dynamically added button?

Try
but.addEventListener('click', yourFunction) Note the absence of parantheses () after the function name. This is because you are assigning the function, not calling it.

Getting last month's date in php

$lastMonth = date('M Y', strtotime("-1 month"));
var_dump($lastMonth);
$lastMonth = date('M Y', mktime(0, 0, 0, date('m') - 1, 1, date('Y')));
var_dump($lastMonth);

How to append data to div using JavaScript?

If you are using jQuery you can use $('#mydiv').append('html content') and it will keep the existing content.

http://api.jquery.com/append/

Sending GET request with Authentication headers using restTemplate

You can use postForObject with an HttpEntity. It would look like this:

HttpHeaders headers = new HttpHeaders();
headers.setContentType(MediaType.APPLICATION_JSON);
headers.set("Authorization", "Bearer "+accessToken);

HttpEntity<String> entity = new HttpEntity<String>(requestJson,headers);
String result = restTemplate.postForObject(url, entity, String.class);

In a GET request, you'd usually not send a body (it's allowed, but it doesn't serve any purpose). The way to add headers without wiring the RestTemplate differently is to use the exchange or execute methods directly. The get shorthands don't support header modification.

The asymmetry is a bit weird on a first glance, perhaps this is going to be fixed in future versions of Spring.

How to set cookies in laravel 5 independently inside controller

If you want to set cookie and get it outside of request, Laravel is not your friend.

Laravel cookies are part of Request, so if you want to do this outside of Request object, use good 'ole PHP setcookie(..) and $_COOKIE to get it.

Removing space from dataframe columns in pandas

  • To remove white spaces:

1) To remove white space everywhere:

df.columns = df.columns.str.replace(' ', '')

2) To remove white space at the beginning of string:

df.columns = df.columns.str.lstrip()

3) To remove white space at the end of string:

df.columns = df.columns.str.rstrip()

4) To remove white space at both ends:

df.columns = df.columns.str.strip()
  • To replace white spaces with other characters (underscore for instance):

5) To replace white space everywhere

df.columns = df.columns.str.replace(' ', '_')

6) To replace white space at the beginning:

df.columns = df.columns.str.replace('^ +', '_')

7) To replace white space at the end:

df.columns = df.columns.str.replace(' +$', '_')

8) To replace white space at both ends:

df.columns = df.columns.str.replace('^ +| +$', '_')

All above applies to a specific column as well, assume you have a column named col, then just do:

df[col] = df[col].str.strip()  # or .replace as above

Oracle date difference to get number of years

For Oracle SQL Developer I was able to calculate the difference in years using the below line of SQL. This was to get Years that were within 0 to 10 years difference. You can do a case like shown in some of the other responses to handle your ifs as well. Happy Coding!

TRUNC((MONTHS_BETWEEN(<DATE_ONE>, <DATE_TWO>) * 31) / 365) > 0 and TRUNC((MONTHS_BETWEEN(<DATE_ONE>, <DATE_TWO>) * 31) / 365) < 10

Angular is automatically adding 'ng-invalid' class on 'required' fields

the accepted answer is correct.. for mobile you can also use this (ng-touched rather ng-dirty)

input.ng-invalid.ng-touched{
  border-bottom: 1px solid #e74c3c !important; 
}

GitHub Error Message - Permission denied (publickey)

I was using github earlier for one of my php project. While using github, I was using ssh instead of https. I had my machine set up like that and every time I used to commit and push the code, it would ask me my rsa key password.

After some days, I stopped working on the php project and forgot my rsa password. Recently, I started working on a java project and moved to bitbucket. Since, I had forgotten the password and there is no way to recover it I guess, I decided to use the https(recommended) protocol for the new project and got the same error asked in the question.

How I solved it?

  1. Ran this command to tell my git to use https instead of ssh:

    git config --global url."https://".insteadOf git://
    
  2. Remove any remote if any

    git remote rm origin
    
  3. Redo everything from git init to git push and it works!

PS: I also un-installed ssh from my machine during the debug process thinking that, removing it will fix the problem. Yes I know!! :)

Button Listener for button in fragment in android

    //sure run it i will also test it
//we make a class that extends with the fragment
    public class Example_3_1 extends Fragment  implements OnClickListener
    {
       View vi;
        EditText t;
        EditText t1;
        Button bu;
 // that are by defult function of fragment extend class
     @Override
       public View onCreateView(LayoutInflater inflater,ViewGroup container,BundlesavedInstanceState) 
       {        
           vi=inflater.inflate(R.layout.example_3_1, container, false);// load the xml file 
           bu=(Button) vi.findViewById(R.id.button1);// get button id from example_3_1 xml file
           bu.setOnClickListener(this); //on button appay click listner
           t=(EditText) vi.findViewById(R.id.editText1);// id get from example_3_1 xml file
           t1=(EditText) vi.findViewById(R.id.editText2);
          return vi; // return the view object,that set the xml file  example_3_1 xml file
       }
       @Override
       public void onClick(View v)//on button click that called
       {

          switch(v.getId())// on run time get id what button os click and get id
          {
          case R.id.button1:        // it mean if button1 click then this work
           t.setText("UMTien");     //set text 
           t1.setText("programming");
           break;
          }
    }     }

Using a cursor with dynamic SQL in a stored procedure

A cursor will only accept a select statement, so if the SQL really needs to be dynamic make the declare cursor part of the statement you are executing. For the below to work your server will have to be using global cursors.

Declare @UserID varchar(100)
declare @sqlstatement nvarchar(4000)
--move declare cursor into sql to be executed
set @sqlstatement = 'Declare  users_cursor CURSOR FOR SELECT userId FROM users'

exec sp_executesql @sqlstatement


OPEN users_cursor
FETCH NEXT FROM users_cursor
INTO @UserId

WHILE @@FETCH_STATUS = 0
BEGIN
Print @UserID
EXEC asp_DoSomethingStoredProc @UserId

FETCH NEXT FROM users_cursor --have to fetch again within loop
INTO @UserId

END
CLOSE users_cursor
DEALLOCATE users_cursor

If you need to avoid using the global cursors, you could also insert the results of your dynamic SQL into a temporary table, and then use that table to populate your cursor.

Declare @UserID varchar(100)
create table #users (UserID varchar(100))

declare @sqlstatement nvarchar(4000)
set @sqlstatement = 'Insert into #users (userID) SELECT userId FROM users'
exec(@sqlstatement)

declare users_cursor cursor for Select UserId from #Users
OPEN users_cursor
FETCH NEXT FROM users_cursor
INTO @UserId

WHILE @@FETCH_STATUS = 0
BEGIN

EXEC asp_DoSomethingStoredProc @UserId

FETCH NEXT FROM users_cursor
INTO @UserId

END
CLOSE users_cursor
DEALLOCATE users_cursor

drop table #users

Maximum number of records in a MySQL database table

mysql int types can do quite a few rows: http://dev.mysql.com/doc/refman/5.0/en/numeric-types.html

unsigned int largest value is 4,294,967,295
unsigned bigint largest value is 18,446,744,073,709,551,615

how to download file in react js

Download file


For downloading you can use multiple ways as been explained above, moreover I will also provide my strategy for this scenario.

  1. npm install --save react-download-link
  2. import DownloadLink from "react-download-link";
  3. React download link for client side cache data
    <DownloadLink 
        label="Download" 
        filename="fileName.txt"
        exportFile={() => "Client side cache data here…"}
    />
    
  4. Download link for client side cache data with Promises
    <DownloadLink
        label="Download with Promise"
        filename="fileName.txt"
        exportFile={() => Promise.resolve("cached data here …")}
    />
    
  5. Download link for data from URL with Promises Function to Fetch data from URL
     getDataFromURL = (url) => new Promise((resolve, reject) => {
        setTimeout(() => {
            fetch(url)
                .then(response => response.text())
                .then(data => {
                    resolve(data)
                });
        });
    }, 2000);
    
  6. DownloadLink component calling Fetch function
    <DownloadLink
          label=”Download”
          filename=”filename.txt”
          exportFile={() => Promise.resolve(this. getDataFromURL (url))}
    />
    

Happy coding! ;)

Get JavaScript object from array of objects by value of property

I don't know why you are against a for loop (presumably you meant a for loop, not specifically for..in), they are fast and easy to read. Anyhow, here's some options.

For loop:

function getByValue(arr, value) {

  for (var i=0, iLen=arr.length; i<iLen; i++) {

    if (arr[i].b == value) return arr[i];
  }
}

.filter

function getByValue2(arr, value) {

  var result  = arr.filter(function(o){return o.b == value;} );

  return result? result[0] : null; // or undefined

}

.forEach

function getByValue3(arr, value) {

  var result = [];

  arr.forEach(function(o){if (o.b == value) result.push(o);} );

  return result? result[0] : null; // or undefined

}

If, on the other hand you really did mean for..in and want to find an object with any property with a value of 6, then you must use for..in unless you pass the names to check.

Example

function getByValue4(arr, value) {
  var o;

  for (var i=0, iLen=arr.length; i<iLen; i++) {
    o = arr[i];

    for (var p in o) {
      if (o.hasOwnProperty(p) && o[p] == value) {
        return o;
      }
    }
  }
}

JavaScript: location.href to open in new window/tab?

You can open it in a new window with window.open('https://support.wwf.org.uk/earth_hour/index.php?type=individual');. If you want to open it in new tab open the current page in two tabs and then alllow the script to run so that both current page and the new page will be obtained.

CSS-moving text from left to right

Hi you can achieve your result with use of <marquee behavior="alternate"></marquee>

HTML

<div class="wrapper">
<marquee behavior="alternate"><span class="marquee">This is a marquee!</span></marquee>
</div>

CSS

.wrapper{
    max-width: 400px;
    background: green;
    height: 40px;
    text-align: right;
}

.marquee {
    background: red;
    white-space: nowrap;
    -webkit-animation: rightThenLeft 4s linear;
}

see the demo:- http://jsfiddle.net/gXdMc/6/

Enabling error display in PHP via htaccess only

I feel like adding more details to the existing answer:

# PHP error handling for development servers
php_flag display_startup_errors on
php_flag display_errors on
php_flag html_errors on
php_flag log_errors on
php_flag ignore_repeated_errors off
php_flag ignore_repeated_source off
php_flag report_memleaks on
php_flag track_errors on
php_value docref_root 0
php_value docref_ext 0
php_value error_log /full/path/to/file/php_errors.log
php_value error_reporting -1
php_value log_errors_max_len 0

Give 777 or 755 permission to the log file and then add the code

<Files php_errors.log>
     Order allow,deny
     Deny from all
     Satisfy All
</Files>

at the end of .htaccess. This will protect your log file.

These options are suited for a development server. For a production server you should not display any error to the end user. So change the display flags to off.

For more information, follow this link: Advanced PHP Error Handling via htaccess

Collection was modified; enumeration operation may not execute

You can copy subscribers dictionary object to a same type of temporary dictionary object and then iterate the temporary dictionary object using foreach loop.

Pipe output and capture exit status in Bash

There is an internal Bash variable called $PIPESTATUS; it’s an array that holds the exit status of each command in your last foreground pipeline of commands.

<command> | tee out.txt ; test ${PIPESTATUS[0]} -eq 0

Or another alternative which also works with other shells (like zsh) would be to enable pipefail:

set -o pipefail
...

The first option does not work with zsh due to a little bit different syntax.

How to change active class while click to another link in bootstrap use jquery?

If you change the classes and load the content within the same function you should be fine.

$(document).ready(function(){
    $('.nav li').click(function(event){
        //remove all pre-existing active classes
        $('.active').removeClass('active');

        //add the active class to the link we clicked
        $(this).addClass('active');

        //Load the content
        //e.g.
        //load the page that the link was pointing to
        //$('#content').load($(this).find(a).attr('href'));      

        event.preventDefault();
    });
});

Get battery level and state in Android

Since SDK 21 LOLLIPOP it is possible to use the following to get current battery level as a percentage:

BatteryManager bm = (BatteryManager) context.getSystemService(BATTERY_SERVICE);
int batLevel = bm.getIntProperty(BatteryManager.BATTERY_PROPERTY_CAPACITY);

Read BatteryManager  |  Android Developers - BATTERY_PROPERTY_CAPACITY

com.android.build.transform.api.TransformException

I had the same option and as soon as I turned off Instant run, it worked fine on my API16 device, but on the API24 device it worked fine with Instant run.

Hope this helps someone having the same issue

How to prevent colliders from passing through each other?

  • Edit ---> Project Settings ---> Time ... decrease "Fixed Timestep" value .. This will solve the problem but it can affect performance negatively.

  • Another solution is could be calculate the coordinates (for example, you have a ball and wall. Ball will hit to wall. So calculate coordinates of wall and set hitting process according these cordinates )

Mysql - How to quit/exit from stored procedure

This works for me :

 CREATE DEFINER=`root`@`%` PROCEDURE `save_package_as_template`( IN package_id int , 
IN bus_fun_temp_id int  , OUT o_message VARCHAR (50) ,
            OUT o_number INT )
 BEGIN

DECLARE  v_pkg_name  varchar(50) ;

DECLARE  v_pkg_temp_id  int(10)  ; 

DECLARE  v_workflow_count INT(10);

-- checking if workflow created for package
select count(*)  INTO v_workflow_count from workflow w where w.package_id = 
package_id ;

this_proc:BEGIN   -- this_proc block start here 

 IF  v_workflow_count = 0 THEN
   select 'no work flow ' as 'workflow_status' ;
    SET o_message ='Work flow is not created for this package.';
    SET  o_number = -2 ;
      LEAVE this_proc;
 END IF;

select 'work flow  created ' as 'workflow_status' ;
-- To  send some message
SET o_message ='SUCCESSFUL';
SET  o_number = 1 ;

  END ;-- this_proc block end here 

END

Redirect stderr to stdout in C shell

What about just

xxx >& /dev/stdout

???

CSS file not refreshing in browser

The fix is called "hard refresh" http://en.wikipedia.org/wiki/Wikipedia:Bypass_your_cache

In most Windows and Linux browsers: Hold down Ctrl and press F5.

In Apple Safari: Hold down ? Shift and click the Reload toolbar button.

In Chrome and Firefox for Mac: Hold down both ? Cmd+? Shift and press R.

Get safe area inset top and bottom heights

Swift 5 Extension

This can be used as a Extension and called with: UIApplication.topSafeAreaHeight

extension UIApplication {
    static var topSafeAreaHeight: CGFloat {
        var topSafeAreaHeight: CGFloat = 0
         if #available(iOS 11.0, *) {
               let window = UIApplication.shared.windows[0]
               let safeFrame = window.safeAreaLayoutGuide.layoutFrame
               topSafeAreaHeight = safeFrame.minY
             }
        return topSafeAreaHeight
    }
}

Extension of UIApplication is optional, can be an extension of UIView or whatever is preferred, or probably even better a global function.

Java Constructor Inheritance

Suppose constructors were inherited... then because every class eventually derives from Object, every class would end up with a parameterless constructor. That's a bad idea. What exactly would you expect:

FileInputStream stream = new FileInputStream();

to do?

Now potentially there should be a way of easily creating the "pass-through" constructors which are fairly common, but I don't think it should be the default. The parameters needed to construct a subclass are often different from those required by the superclass.

How to generate a unique hash code for string input in android...?

A few line of java code.

public static void main(String args[]) throws Exception{
       String str="test string";
       MessageDigest messageDigest=MessageDigest.getInstance("MD5");
       messageDigest.update(str.getBytes(),0,str.length());
       System.out.println("MD5: "+new BigInteger(1,messageDigest.digest()).toString(16));
}

Effective swapping of elements of an array in Java

inplace swapping (incase you already didn't know) can save a bit of space by not creating a temp variable.

arr[i] = arr[i] + arr[j];
arr[j] = arr[i] - arr[j];
arr[i] = arr[i] - arr[j];

How do you add a JToken to an JObject?

TL;DR: You should add a JProperty to a JObject. Simple. The index query returns a JValue, so figure out how to get the JProperty instead :)


The accepted answer is not answering the question as it seems. What if I want to specifically add a JProperty after a specific one? First, lets start with terminologies which really had my head worked up.

  • JToken = The mother of all other types. It can be A JValue, JProperty, JArray, or JObject. This is to provide a modular design to the parsing mechanism.
  • JValue = any Json value type (string, int, boolean).
  • JProperty = any JValue or JContainer (see below) paired with a name (identifier). For example "name":"value".
  • JContainer = The mother of all types which contain other types (JObject, JValue).
  • JObject = a JContainer type that holds a collection of JProperties
  • JArray = a JContainer type that holds a collection JValue or JContainer.

Now, when you query Json item using the index [], you are getting the JToken without the identifier, which might be a JContainer or a JValue (requires casting), but you cannot add anything after it, because it is only a value. You can change it itself, query more deep values, but you cannot add anything after it for example.

What you actually want to get is the property as whole, and then add another property after it as desired. For this, you use JOjbect.Property("name"), and then create another JProperty of your desire and then add it after this using AddAfterSelf method. You are done then.

For more info: http://www.newtonsoft.com/json/help/html/ModifyJson.htm

This is the code I modified.

public class Program
{
  public static void Main()
  {
    try
    {
      string jsonText = @"
      {
        ""food"": {
          ""fruit"": {
            ""apple"": {
              ""colour"": ""red"",
              ""size"": ""small""
            },
            ""orange"": {
              ""colour"": ""orange"",
              ""size"": ""large""
            }
          }
        }
      }";

      var foodJsonObj = JObject.Parse(jsonText);
      var bananaJson = JObject.Parse(@"{ ""banana"" : { ""colour"": ""yellow"", ""size"": ""medium""}}");

      var fruitJObject = foodJsonObj["food"]["fruit"] as JObject;
      fruitJObject.Property("orange").AddAfterSelf(new JProperty("banana", fruitJObject));

      Console.WriteLine(foodJsonObj.ToString());
    }
    catch (Exception ex)
    {
      Console.WriteLine(ex.GetType().Name + ": " + ex.Message);
    }
  }
}

Search for value in DataGridView in a column

"MyTable".DefaultView.RowFilter = " LIKE '%" + textBox1.Text + "%'"; this.dataGridView1.DataSource = "MyTable".DefaultView;

How about the relation to the database connections and the Datatable? And how should i set the DefaultView correct?

I use this code to get the data out:

con = new System.Data.SqlServerCe.SqlCeConnection();
con.ConnectionString = "Data Source=C:\\Users\\mhadj\\Documents\\Visual Studio 2015\\Projects\\data_base_test_2\\Sample.sdf";
con.Open();

DataTable dt = new DataTable();

adapt = new System.Data.SqlServerCe.SqlCeDataAdapter("select * from tbl_Record", con);        
adapt.Fill(dt);        
dataGridView1.DataSource = dt;
con.Close();

How can I disable an <option> in a <select> based on its value in JavaScript?

For some reason other answers are unnecessarily complex, it's easy to do it in one line in pure JavaScript:

Array.prototype.find.call(selectElement.options, o => o.value === optionValue).disabled = true;

or

selectElement.querySelector('option[value="'+optionValue.replace(/["\\]/g, '\\$&')+'"]').disabled = true;

The performance depends on the number of the options (the more the options, the slower the first one) and whether you can omit the escaping (the replace call) from the second one. Also the first one uses Array.find and arrow functions that are not available in IE11.

Split an NSString to access one particular piece

NSArray* foo = [@"10/04/2011" componentsSeparatedByString: @"/"];
NSString* firstBit = [foo objectAtIndex: 0];

Update 7/3/2018:

Now that the question has acquired a Swift tag, I should add the Swift way of doing this. It's pretty much as simple:

let substrings = "10/04/2011".split(separator: "/")
let firstBit = substrings[0]

Although note that it gives you an array of Substring. If you need to convert these back to ordinary strings, use map

let strings = "10/04/2011".split(separator: "/").map{ String($0) }
let firstBit = strings[0]

or

let firstBit = String(substrings[0])

How to get a div to resize its height to fit container?

If the trick using position:absolute, position:relative and top/left/bottom/right: 0px is not appropriate for your situation, you could try:

#nav {
    height: inherit;
}

This worked on one of our pages, although I am not sure exactly what other conditions were needed for it to succeed!

Printing Even and Odd using two Threads in Java

Please use the following code to print odd and even number in a proper order along with desired messages.

package practice;


class Test {

  private static boolean oddFlag = true;
  int count = 1;

  private void oddPrinter() {
    synchronized (this) {
      while(true) {
        try {
          if(count < 10) {
            if(oddFlag) {
              Thread.sleep(500);
              System.out.println(Thread.currentThread().getName() + ": " + count++);
              oddFlag = !oddFlag;
              notifyAll();
            }
            else {
              wait();
            }
          }
          else {
            System.out.println("Odd Thread finished");
            notify();
            break;
          }
        }
        catch (InterruptedException e) {
          e.printStackTrace();
        }
      }
    }
  }

  private void evenPrinter() {
    synchronized (this) {
      while (true) {
        try {
          if(count < 10) {
            if(!oddFlag) {
              Thread.sleep(500);
              System.out.println(Thread.currentThread().getName() + ": " + count++);
              oddFlag = !oddFlag;
              notify();
            }
            else {
              wait();
            }
          }
          else {
            System.out.println("Even Thread finished");
            notify();
            break;
          }
        }
        catch (InterruptedException e) {
          e.printStackTrace();
        }
      }
    }
  }


  public static void main(String[] args) throws InterruptedException{
    final Test test = new Test();

    Thread t1 = new Thread(new Runnable() {
      public void run() {
        test.oddPrinter();
      }
    }, "Thread 1");

    Thread t2 = new Thread(new Runnable() {
      public void run() {
        test.evenPrinter();
      }
    }, "Thread 2");

    t1.start();
    t2.start();

    t1.join();
    t2.join();

    System.out.println("Main thread finished");
  }
}

How to group an array of objects by key

I love to write it with no dependency/complexity just pure simple js.

_x000D_
_x000D_
const mp = {}
const cars = [
  {
    model: 'Imaginary space craft SpaceX model',
    year: '2025'
  },
  {
    make: 'audi',
    model: 'r8',
    year: '2012'
  },
  {
    make: 'audi',
    model: 'rs5',
    year: '2013'
  },
  {
    make: 'ford',
    model: 'mustang',
    year: '2012'
  },
  {
    make: 'ford',
    model: 'fusion',
    year: '2015'
  },
  {
    make: 'kia',
    model: 'optima',
    year: '2012'
  }
]

cars.forEach(c => {
  if (!c.make) return // exit (maybe add them to a "no_make" category)

  if (!mp[c.make]) mp[c.make] = [{ model: c.model, year: c.year }]
  else mp[c.make].push({ model: c.model, year: c.year })
})

console.log(mp)
_x000D_
_x000D_
_x000D_

Easy way to convert a unicode list to a list containing python strings?

[str(x) for x in EmployeeList] would do a conversion, but it would fail if the unicode string characters do not lie in the ascii range.

>>> EmployeeList = [u'1001', u'Karick', u'14-12-2020', u'1$']
>>> [str(x) for x in EmployeeList]
['1001', 'Karick', '14-12-2020', '1$']


>>> EmployeeList = [u'1001', u'????', u'14-12-2020', u'1$']
>>> [str(x) for x in EmployeeList]
Traceback (most recent call last):
  File "<stdin>", line 1, in <module>
UnicodeEncodeError: 'ascii' codec can't encode characters in position 0-3: ordinal not in range(128)

ImportError: No module named pip

In terminal try this:

ls -lA /usr/local/bin | grep pip

in my case i get:

-rwxr-xr-x 1 root  root      284 ??? 13 16:20 pip
-rwxr-xr-x 1 root  root      204 ??? 27 16:37 pip2
-rwxr-xr-x 1 root  root      204 ??? 27 16:37 pip2.7
-rwxr-xr-x 1 root  root      292 ??? 13 16:20 pip-3.4

So pip2 || pip2.7 in my case works, and pip

Difference between fprintf, printf and sprintf?

printf outputs to the standard output stream (stdout)

fprintf goes to a file handle (FILE*)

sprintf goes to a buffer you allocated. (char*)

Dropdownlist width in IE

Its tested in all version of IE, Chrome, FF & Safari

JavaScript code:

<!-- begin hiding
function expandSELECT(sel) {
  sel.style.width = '';
}

function contractSELECT(sel) {
  sel.style.width = '100px';
}
// end hiding -->

Html code:

<select name="sideeffect" id="sideeffect"  style="width:100px;" onfocus="expandSELECT(this);" onblur="contractSELECT(this);" >
  <option value="0" selected="selected" readonly="readonly">Select</option>
  <option value="1" >Apple</option>
  <option value="2" >Orange + Banana + Grapes</option>

jQuery get the id/value of <li> element after click function

you can get the value of the respective li by using this method after click

HTML:-

<!DOCTYPE html>
<html>
<head>
    <title>show the value of li</title>
    <link rel="stylesheet"  href="pathnameofcss">
</head>
<body>

    <div id="user"></div>


    <script src="https://ajax.googleapis.com/ajax/libs/jquery/1.9.1/jquery.min.js"></script>
    <ul id="pageno">
    <li value="1">1</li>
    <li value="2">2</li>
    <li value="3">3</li>
    <li value="4">4</li>
    <li value="5">5</li>
    <li value="6">6</li>
    <li value="7">7</li>
    <li value="8">8</li>
    <li value="9">9</li>
    <li value="10">10</li>

    </ul>

    <script src="pathnameofjs" type="text/javascript"></script>
</body>
</html>

JS:-

$("li").click(function ()
{       
var a = $(this).attr("value");

$("#user").html(a);//here the clicked value is showing in the div name user
console.log(a);//here the clicked value is showing in the console
});

CSS:-

ul{
display: flex;
list-style-type:none;
padding: 20px;
}

li{
padding: 20px;
}

how to configure lombok in eclipse luna

Here is the complete steps to be followed, you wont see any issues.

1. Download Lombok Jar File - Its better to have a Maven/Gradle dependency in your application. The maven depency can be found here: https://mvnrepository.com/artifact/org.projectlombok/lombok

2. Start Lombok Installation -
Once the jar downloaded in Local repository, goto the jar location from command prompt and run the following command java -jar lombok-1.16.18.jar and we should be greeted by Lombok installation window provided by lombok like this.

3. Give Lombok Install Path - Now click on the “Specify Location” button and locate the eclipse.exe/STS.exe path under eclipse installation folder like this.

enter image description here

4. Finish Lombok Installation - Now we need to finally install this by clicking the “Install/Update” button and we should finished installing lombok in eclipse and we are ready to use its hidden power. Final screen will look like,

enter image description here

5. Please make sure to add below entry into the STS.ini file, if its not already there.

-vmargs -javaagent:lombok.jar

Note: After doing all this if this doesn't worked then make sure to change the workspace and build the code again. It will work.

AngularJS ng-repeat handle empty list case

And if you want to use this with a filtered list here's a neat trick:

<ul>
    <li ng-repeat="item in filteredItems  = (items | filter:keyword)">
        ...
    </li>
</ul>
<div ng-hide="filteredItems.length">No items found</div>

Sorting a Dictionary in place with respect to keys

By design, dictionaries are not sortable. If you need this capability in a dictionary, look at SortedDictionary instead.

How to check certificate name and alias in keystore files?

In order to get all the details I had to add the -v option to romaintaz answer:

keytool -v -list -keystore <FileName>.keystore

How to add a class to a given element?

document.getElementById('some_id').className+='  someclassname'

OR:

document.getElementById('some_id').classList.add('someclassname')

First approach helped in adding the class when second approach didn't work.
Don't forget to keep a space in front of the ' someclassname' in the first approach.

For removal you can use:

document.getElementById('some_id').classList.remove('someclassname')

C function that counts lines in file

You're opening a file, then passing the file pointer to a function that only wants a file name to open the file itself. You can simplify your call to;

void main(void)
{
  printf("LINES: %d\n",countlines("Test.txt"));
}

EDIT: You're changing the question around so it's very hard to answer; at first you got your change to main() wrong, you forgot that the first parameter is argc, so it crashed. Now you have the problem of;

if (fp == NULL);   // <-- note the extra semicolon that is the only thing 
                   //     that runs conditionally on the if 
  return 0;        // Always runs and returns 0

which will always return 0. Remove that extra semicolon, and you should get a reasonable count.

How to Identify port number of SQL server

Visually you can open "SQL Server Configuration Manager" and check properties of "Network Configuration":

SQL Server Configuration

How to extract table as text from the PDF using Python?

This answer is for anyone encountering pdfs with images and needing to use OCR. I could not find a workable off-the-shelf solution; nothing that gave me the accuracy I needed.

Here are the steps I found to work.

  1. Use pdfimages from https://poppler.freedesktop.org/ to turn the pages of the pdf into images.

  2. Use Tesseract to detect rotation and ImageMagick mogrify to fix it.

  3. Use OpenCV to find and extract tables.

  4. Use OpenCV to find and extract each cell from the table.

  5. Use OpenCV to crop and clean up each cell so that there is no noise that will confuse OCR software.

  6. Use Tesseract to OCR each cell.

  7. Combine the extracted text of each cell into the format you need.

I wrote a python package with modules that can help with those steps.

Repo: https://github.com/eihli/image-table-ocr

Docs & Source: https://eihli.github.io/image-table-ocr/pdf_table_extraction_and_ocr.html

Some of the steps don't require code, they take advantage of external tools like pdfimages and tesseract. I'll provide some brief examples for a couple of the steps that do require code.

  1. Finding tables:

This link was a good reference while figuring out how to find tables. https://answers.opencv.org/question/63847/how-to-extract-tables-from-an-image/

import cv2

def find_tables(image):
    BLUR_KERNEL_SIZE = (17, 17)
    STD_DEV_X_DIRECTION = 0
    STD_DEV_Y_DIRECTION = 0
    blurred = cv2.GaussianBlur(image, BLUR_KERNEL_SIZE, STD_DEV_X_DIRECTION, STD_DEV_Y_DIRECTION)
    MAX_COLOR_VAL = 255
    BLOCK_SIZE = 15
    SUBTRACT_FROM_MEAN = -2

    img_bin = cv2.adaptiveThreshold(
        ~blurred,
        MAX_COLOR_VAL,
        cv2.ADAPTIVE_THRESH_MEAN_C,
        cv2.THRESH_BINARY,
        BLOCK_SIZE,
        SUBTRACT_FROM_MEAN,
    )
    vertical = horizontal = img_bin.copy()
    SCALE = 5
    image_width, image_height = horizontal.shape
    horizontal_kernel = cv2.getStructuringElement(cv2.MORPH_RECT, (int(image_width / SCALE), 1))
    horizontally_opened = cv2.morphologyEx(img_bin, cv2.MORPH_OPEN, horizontal_kernel)
    vertical_kernel = cv2.getStructuringElement(cv2.MORPH_RECT, (1, int(image_height / SCALE)))
    vertically_opened = cv2.morphologyEx(img_bin, cv2.MORPH_OPEN, vertical_kernel)

    horizontally_dilated = cv2.dilate(horizontally_opened, cv2.getStructuringElement(cv2.MORPH_RECT, (40, 1)))
    vertically_dilated = cv2.dilate(vertically_opened, cv2.getStructuringElement(cv2.MORPH_RECT, (1, 60)))

    mask = horizontally_dilated + vertically_dilated
    contours, hierarchy = cv2.findContours(
        mask, cv2.RETR_EXTERNAL, cv2.CHAIN_APPROX_SIMPLE,
    )

    MIN_TABLE_AREA = 1e5
    contours = [c for c in contours if cv2.contourArea(c) > MIN_TABLE_AREA]
    perimeter_lengths = [cv2.arcLength(c, True) for c in contours]
    epsilons = [0.1 * p for p in perimeter_lengths]
    approx_polys = [cv2.approxPolyDP(c, e, True) for c, e in zip(contours, epsilons)]
    bounding_rects = [cv2.boundingRect(a) for a in approx_polys]

    # The link where a lot of this code was borrowed from recommends an
    # additional step to check the number of "joints" inside this bounding rectangle.
    # A table should have a lot of intersections. We might have a rectangular image
    # here though which would only have 4 intersections, 1 at each corner.
    # Leaving that step as a future TODO if it is ever necessary.
    images = [image[y:y+h, x:x+w] for x, y, w, h in bounding_rects]
    return images
  1. Extract cells from table.

This is very similar to 2, so I won't include all the code. The part I will reference will be in sorting the cells.

We want to identify the cells from left-to-right, top-to-bottom.

We’ll find the rectangle with the most top-left corner. Then we’ll find all of the rectangles that have a center that is within the top-y and bottom-y values of that top-left rectangle. Then we’ll sort those rectangles by the x value of their center. We’ll remove those rectangles from the list and repeat.

def cell_in_same_row(c1, c2):
    c1_center = c1[1] + c1[3] - c1[3] / 2
    c2_bottom = c2[1] + c2[3]
    c2_top = c2[1]
    return c2_top < c1_center < c2_bottom

orig_cells = [c for c in cells]
rows = []
while cells:
    first = cells[0]
    rest = cells[1:]
    cells_in_same_row = sorted(
        [
            c for c in rest
            if cell_in_same_row(c, first)
        ],
        key=lambda c: c[0]
    )

    row_cells = sorted([first] + cells_in_same_row, key=lambda c: c[0])
    rows.append(row_cells)
    cells = [
        c for c in rest
        if not cell_in_same_row(c, first)
    ]

# Sort rows by average height of their center.
def avg_height_of_center(row):
    centers = [y + h - h / 2 for x, y, w, h in row]
    return sum(centers) / len(centers)

rows.sort(key=avg_height_of_center)

TCPDF ERROR: Some data has already been output, can't send PDF file

This problem means you have headers. Deletes tags

?>

at the end of your code and make sure not to have whitespace at the beginning.

g++ ld: symbol(s) not found for architecture x86_64

finally solved my problem.

I created a new project in XCode with the sources and changed the C++ Standard Library from the default libc++ to libstdc++ as in this and this.

System.Data.SqlClient.SqlException: Invalid object name 'dbo.Projects'

This maybe due to an incorrect table name from where you are fetching the data. Please verify the name of the table you mentioned in asmx file and the table created in database.

omp parallel vs. omp parallel for

I don't think there is any difference, one is a shortcut for the other. Although your exact implementation might deal with them differently.

The combined parallel worksharing constructs are a shortcut for specifying a parallel construct containing one worksharing construct and no other statements. Permitted clauses are the union of the clauses allowed for the parallel and worksharing contructs.

Taken from http://www.openmp.org/mp-documents/OpenMP3.0-SummarySpec.pdf

The specs for OpenMP are here:

https://openmp.org/specifications/

Should I use pt or px?

A pt is 1/72th of an inch and is a useless measure for anything that is rendered on a device which doesn't calculate the DPI correctly. This makes it a reasonable choice for printing and a dreadful choice for use on screen.

A px is a pixel, which will map on to a screen pixel in most cases.

CSS provides a bunch of other units, and which one you should choose depends on what you are setting the size of.

A pixel is great if you need to size something to match an image, or if you want a thin border.

Percentages are great for font sizes as, if you use them consistently, you get font sizes proportional to the user's preference.

Ems are great when you want an element to size itself based on the font size (so a paragraph might get wider if the font size is larger)

… and so on.

Is there any way to wait for AJAX response and halt execution?

Try this code. it worked for me.

 function getInvoiceID(url, invoiceId) {
    return $.ajax({
        type: 'POST',
        url: url,
        data: { invoiceId: invoiceId },
        async: false,
    });
}
function isInvoiceIdExists(url, invoiceId) {
    $.when(getInvoiceID(url, invoiceId)).done(function (data) {
        if (!data) {

        }
    });
}

How can I generate Unix timestamps?

The unix 'date' command is surprisingly versatile.

date -j -f "%a %b %d %T %Z %Y" "`date`" "+%s"

Takes the output of date, which will be in the format defined by -f, and then prints it out (-j says don't attempt to set the date) in the form +%s, seconds since epoch.

While variable is not defined - wait

Shorter way:

   var queue = function (args){
      typeof variableToCheck !== "undefined"? doSomething(args) : setTimeout(function () {queue(args)}, 2000);
};

You can also pass arguments

Rotate a div using javascript

Can be pretty easily done assuming you're using jQuery and css3:

http://jsfiddle.net/S7JDU/8/

HTML:

<div id="clicker">Click Here</div>
<div id="rotating"></div>

CSS:

#clicker { 
    width: 100px; 
    height: 100px; 
    background-color: Green; 
}

#rotating { 
    width: 100px; 
    height: 100px; 
    background-color: Red; 
    margin-top: 50px; 
    -webkit-transition: all 0.3s ease-in-out;
    -moz-transition: all 0.3s ease-in-out;
    -o-transition: all 0.3s ease-in-out;
    transition: all 0.3s ease-in-out;
}

.rotated { 
    transform:rotate(25deg); 
    -webkit-transform:rotate(25deg); 
    -moz-transform:rotate(25deg); 
    -o-transform:rotate(25deg); 
}

JS:

$(document).ready(function() {
    $('#clicker').click(function() {
        $('#rotating').toggleClass('rotated');
    });
});

Maven plugins can not be found in IntelliJ

I just delete all my maven plugins stored in .m2\repository\org\apache\maven\plugins, and IntelliJ downloaded all the plugins again a it solve my problem and it worked fine for me!!!

C#: List All Classes in Assembly

I'd just like to add to Jon's example. To get a reference to your own assembly, you can use:

Assembly myAssembly = Assembly.GetExecutingAssembly();

System.Reflection namespace.

If you want to examine an assembly that you have no reference to, you can use either of these:

Assembly assembly = Assembly.ReflectionOnlyLoad(fullAssemblyName);
Assembly assembly = Assembly.ReflectionOnlyLoadFrom(fileName);

If you intend to instantiate your type once you've found it:

Assembly assembly = Assembly.Load(fullAssemblyName);
Assembly assembly = Assembly.LoadFrom(fileName);

See the Assembly class documentation for more information.

Once you have the reference to the Assembly object, you can use assembly.GetTypes() like Jon already demonstrated.

Can a PDF file's print dialog be opened with Javascript?

Just figured out how to do this within the PDF itself - if you have acrobat pro, go to your pages tab, right click on the thumbnail for the first page, and click page properties. Click on the actions tab at the top of the window and under select trigger choose page open. Under select action choose "run a javascript". Then in the javascript window, type this:

this.print({bUI: false, bSilent: true, bShrinkToFit: true});

This will print your document without a dialogue to the default printer on your machine. If you want the print dialog, just change bUI to true, bSilent to false, and optionally, remove the shrink to fit parameter.

Auto-printing PDF!

Get user's current location

as PHP relies on server, the real-time location cant be provided only static location can be provided it is better to avoid to rely on the JS for location rather than using php. But there is a need to post the js data to php so that it can be easily be accesible to program on server

How to detect escape key press with pure JS or jQuery?

i think the simplest way is vanilla javascript:

document.onkeyup = function(event) {
   if (event.keyCode === 27){
     //do something here
   }
}

Updated: Changed key => keyCode

Convert int to a bit array in .NET

Use the BitArray class.

int value = 3;
BitArray b = new BitArray(new int[] { value });

If you want to get an array for the bits, you can use the BitArray.CopyTo method with a bool[] array.

bool[] bits = new bool[b.Count];
b.CopyTo(bits, 0);

Note that the bits will be stored from least significant to most significant, so you may wish to use Array.Reverse.

And finally, if you want get 0s and 1s for each bit instead of booleans (I'm using a byte to store each bit; less wasteful than an int):

byte[] bitValues = bits.Select(bit => (byte)(bit ? 1 : 0)).ToArray();

Best/Most Comprehensive API for Stocks/Financial Data

Markit On Demand provides a set of free financial APIs for playing around with. Looks like there is a stock quote API, a stock ticker/company search and a charting API available. Look at http://dev.markitondemand.com

How to use double or single brackets, parentheses, curly braces

Truncate the contents of a variable

$ var="abcde"; echo ${var%d*}
abc

Make substitutions similar to sed

$ var="abcde"; echo ${var/de/12}
abc12

Use a default value

$ default="hello"; unset var; echo ${var:-$default}
hello

TypeError: got multiple values for argument

This also happens if you forget selfdeclaration inside class methods.

Example:

class Example():
    def is_overlapping(x1, x2, y1, y2):
        # Thanks to https://stackoverflow.com/a/12888920/940592
        return max(x1, y1) <= min(x2, y2)

Fails calling it like self.is_overlapping(x1=2, x2=4, y1=3, y2=5) with:

{TypeError} is_overlapping() got multiple values for argument 'x1'

WORKS:

class Example():
    def is_overlapping(self, x1, x2, y1, y2):
        # Thanks to https://stackoverflow.com/a/12888920/940592
        return max(x1, y1) <= min(x2, y2)

CSS transition shorthand with multiple properties?

I made it work with this:

.element {
   transition: height 3s ease-out, width 5s ease-in;
}

How do I bind the enter key to a function in tkinter?

Try running the following program. You just have to be sure your window has the focus when you hit Return--to ensure that it does, first click the button a couple of times until you see some output, then without clicking anywhere else hit Return.

import tkinter as tk

root = tk.Tk()
root.geometry("300x200")

def func(event):
    print("You hit return.")
root.bind('<Return>', func)

def onclick():
    print("You clicked the button")

button = tk.Button(root, text="click me", command=onclick)
button.pack()

root.mainloop()

Then you just have tweak things a little when making both the button click and hitting Return call the same function--because the command function needs to be a function that takes no arguments, whereas the bind function needs to be a function that takes one argument(the event object):

import tkinter as tk

root = tk.Tk()
root.geometry("300x200")

def func(event):
    print("You hit return.")

def onclick(event=None):
    print("You clicked the button")

root.bind('<Return>', onclick)

button = tk.Button(root, text="click me", command=onclick)
button.pack()

root.mainloop()

Or, you can just forgo using the button's command argument and instead use bind() to attach the onclick function to the button, which means the function needs to take one argument--just like with Return:

import tkinter as tk

root = tk.Tk()
root.geometry("300x200")

def func(event):
    print("You hit return.")

def onclick(event):
    print("You clicked the button")

root.bind('<Return>', onclick)

button = tk.Button(root, text="click me")
button.bind('<Button-1>', onclick)
button.pack()

root.mainloop()

Here it is in a class setting:

import tkinter as tk

class Application(tk.Frame):
    def __init__(self):
        self.root = tk.Tk()
        self.root.geometry("300x200")

        tk.Frame.__init__(self, self.root)
        self.create_widgets()

    def create_widgets(self):
        self.root.bind('<Return>', self.parse)
        self.grid()

        self.submit = tk.Button(self, text="Submit")
        self.submit.bind('<Button-1>', self.parse)
        self.submit.grid()

    def parse(self, event):
        print("You clicked?")

    def start(self):
        self.root.mainloop()


Application().start()

jQuery issue - #<an Object> has no method

This problem can also arise if you include jQuery more than once.

How do I add an element to array in reducer of React native redux?

push does not return the array, but the length of it (docs), so what you are doing is replacing the array with its length, losing the only reference to it that you had. Try this:

import {ADD_ITEM} from '../Actions/UserActions'
const initialUserState = {

    arr:[]
}

export default function userState(state = initialUserState, action){
     console.log(arr);
     switch (action.type){
        case ADD_ITEM :
          return { 
             ...state,
             arr:[...state.arr, action.newItem]
        }

        default:return state
     }
}

Dialogs / AlertDialogs: How to "block execution" while dialog is up (.NET-style)

I am new to the Android/Java world and was surprised to find out here (unless I don't understand what I read) that modal dialogs don't work. For some very obscure reasons for me at the moment, I got this "ShowMessage" equivalent with an ok button that works on my tablet in a very modal manner.

From my TDialogs.java module:

class DialogMes 
{

  AlertDialog alertDialog ;
  private final Message NO_HANDLER = null;
  public DialogMes(Activity parent,String aTitle, String mes)
  {
    alertDialog = new AlertDialog.Builder(parent).create();
    alertDialog.setTitle(aTitle);    
    alertDialog.setMessage(mes) ;  
    alertDialog.setButton("OK",NO_HANDLER) ;    
    alertDialog.show() ; 
  } 
}

Here's part of the test code:

public class TestDialogsActivity extends Activity implements DlgConfirmEvent
{

   @Override
  public void onCreate(Bundle savedInstanceState)
  {
    super.onCreate(savedInstanceState);
    setContentView(R.layout.main);
    Button btShowMessage = (Button) findViewById(R.id.btShowMessage);
    btShowMessage.setOnClickListener(new View.OnClickListener() {
      public void onClick(View view) 
      {
        DialogMes dlgMes = new DialogMes( TestDialogsActivity.this,"Message","life is good") ;                
      }  
    }); 

I also implemented a modal Yes/No dialog following the interface approach suggested above by JohnnyBeGood, and it works pretty good too.

Correction:

My answer is not relevant to the question that I misunderstood. For some reason, I interpreted M. Romain Guy "you don't want to do that" as a no no to modal dialogs. I should have read: "you don't want to do that...this way".

I apologize.

What does the colon (:) operator do?

Since most for loops are very similar, Java provides a shortcut to reduce the amount of code required to write the loop called the for each loop.

Here is an example of the concise for each loop:

for (Integer grade : quizGrades){
      System.out.println(grade);
 }    

In the example above, the colon (:) can be read as "in". The for each loop altogether can be read as "for each Integer element (called grade) in quizGrades, print out the value of grade."

How to get the last element of an array in Ruby?

One other way, using the splat operator:

*a, last = [1, 3, 4, 5]

STDOUT:
a: [1, 3, 4]
last: 5

How do I ignore all files in a folder with a Git repository in Sourcetree?

  • Ignore all files in folder with Git in Sourcetree:

Ignore all files in folder with Git in Sourcetree

Getting the location from an IP address

This question is protected, which I understand. However, I do not see an answer here, what I see is a lot of people showing what they came up with from having the same question.

There are currently five Regional Internet Registries with varying degrees of functionality that serve as the first point of contact with regard to IP ownership. The process is in flux, which is why the various services here work sometimes and don't at other times.

Who Is is (obviously) an ancient TCP protocol, however -- the way it worked originally was by connection to port 43, which makes it problematic getting it routed through leased connections, through firewalls...etc.

At this moment -- most Who Is is done via RESTful HTTP and ARIN, RIPE and APNIC have RESTful services that work. LACNIC's returns a 503 and AfriNIC apparently has no such API. (All have online services, however.)

That will get you -- the address of the IP's registered owner, but -- not your client's location -- you must get that from them and also -- you have to ask for it. Also, proxies are the least of your worries when validating the IP that you think is the originator.

People do not appreciate the notion that they are being tracked, so -- my thoughts are -- get it from your client directly and with their permission and expect a lot to balk at the notion.

Start an external application from a Google Chrome Extension?

You can't launch arbitrary commands, but if your users are willing to go through some extra setup, you can use custom protocols.

E.g. you have the users set things up so that some-app:// links start "SomeApp", and then in my-awesome-extension you open a tab pointing to some-app://some-data-the-app-wants, and you're good to go!

How does jQuery work when there are multiple elements with the same ID value?

jQuery's id selector only returns one result. The descendant and multiple selectors in the second and third statements are designed to select multiple elements. It's similar to:

Statement 1

var length = document.getElementById('a').length;

...Yields one result.

Statement 2

var length = 0;
for (i=0; i<document.body.childNodes.length; i++) {
    if (document.body.childNodes.item(i).id == 'a') {
        length++;
    }
}

...Yields two results.

Statement 3

var length = document.getElementById('a').length + document.getElementsByTagName('div').length;

...Also yields two results.

Using boolean values in C

You could use _Bool, but the return value must be an integer (1 for true, 0 for false). However, It's recommended to include and use bool as in C++, as said in this reply from daniweb forum, as well as this answer, from this other stackoverflow question:

_Bool: C99's boolean type. Using _Bool directly is only recommended if you're maintaining legacy code that already defines macros for bool, true, or false. Otherwise, those macros are standardized in the header. Include that header and you can use bool just like you would in C++.

javascript regular expression to check for IP addresses

Throwing in a late contribution:

^(?!\.)((^|\.)([1-9]?\d|1\d\d|2(5[0-5]|[0-4]\d))){4}$

Of the answers I checked, they're either longer or incomplete in their verification. Longer, in my experience, means harder to overlook and therefore more prone to be erroneous. And I like to avoid repeating similar patters, for the same reason.

The main part is, of course, the test for a number - 0 to 255, but also making sure it doesn't allow initial zeroes (except for when it's a single one):

[1-9]?\d|1\d\d|2(5[0-5]|[0-4]\d)

Three alternations - one for sub 100: [1-9]?\d, one for 100-199: 1\d\d and finally 200-255: 2(5[0-5]|[0-4]\d).

This is preceded by a test for start of line or a dot ., and this whole expression is tested for 4 times by the appended {4}.

This complete test for four byte representations is started by testing for start of line followed by a negative look ahead to avoid addresses starting with a .: ^(?!\.), and ended with a test for end of line ($).

See some samples here at regex101.

How to return more than one value from a function in Python?

You separate the values you want to return by commas:

def get_name():
   # you code
   return first_name, last_name

The commas indicate it's a tuple, so you could wrap your values by parentheses:

return (first_name, last_name)

Then when you call the function you a) save all values to one variable as a tuple, or b) separate your variable names by commas

name = get_name() # this is a tuple
first_name, last_name = get_name()
(first_name, last_name) = get_name() # You can put parentheses, but I find it ugly

How do I Search/Find and Replace in a standard string?

I believe this would work. It takes const char*'s as a parameter.

//params find and replace cannot be NULL
void FindAndReplace( std::string& source, const char* find, const char* replace )
{
   //ASSERT(find != NULL);
   //ASSERT(replace != NULL);
   size_t findLen = strlen(find);
   size_t replaceLen = strlen(replace);
   size_t pos = 0;

   //search for the next occurrence of find within source
   while ((pos = source.find(find, pos)) != std::string::npos)
   {
      //replace the found string with the replacement
      source.replace( pos, findLen, replace );

      //the next line keeps you from searching your replace string, 
      //so your could replace "hello" with "hello world" 
      //and not have it blow chunks.
      pos += replaceLen; 
   }
}

C# 'or' operator?

C# supports two boolean or operators: the single bar | and the double-bar ||.

The difference is that | always checks both the left and right conditions, while || only checks the right-side condition if it's necessary (if the left side evaluates to false).

This is significant when the condition on the right-side involves processing or results in side effects. (For example, if your ErrorDumpWriter.Close method took a while to complete or changed something's state.)

iPhone SDK:How do you play video inside a view? Rather than fullscreen

As of the 3.2 SDK you can access the view property of MPMoviePlayerController, modify its frame and add it to your view hierarchy.

MPMoviePlayerController *player = [[MPMoviePlayerController alloc] initWithContentURL:[NSURL fileURLWithPath:url]];
player.view.frame = CGRectMake(184, 200, 400, 300);
[self.view addSubview:player.view];
[player play];

There's an example here: http://www.devx.com/wireless/Article/44642/1954

Extract Number from String in Python

Your regex looks correct. Are you sure you haven't made a mistake with the variable names? In your code above you mixup total_hotel_reviews_string and str.

>>> import re
>>> s = "3158 reviews"
>>> 
>>> print(re.findall("\d+", s))
['3158']

Android: combining text & image on a Button or ImageButton

 <Button android:id="@+id/imeageTextBtn" 
        android:layout_width="240dip"
        android:layout_height="wrap_content"
        android:text="Side Icon With Text Button"
        android:textSize="20sp"
        android:drawableLeft="@drawable/left_side_icon"         
        />   

correct way to define class variables in Python

I think this sample explains the difference between the styles:

james@bodacious-wired:~$cat test.py 
#!/usr/bin/env python

class MyClass:
    element1 = "Hello"

    def __init__(self):
        self.element2 = "World"

obj = MyClass()

print dir(MyClass)
print "--"
print dir(obj)
print "--"
print obj.element1 
print obj.element2
print MyClass.element1 + " " + MyClass.element2
james@bodacious-wired:~$./test.py 
['__doc__', '__init__', '__module__', 'element1']
--
['__doc__', '__init__', '__module__', 'element1', 'element2']
--
Hello World
Hello
Traceback (most recent call last):
  File "./test.py", line 17, in <module>
    print MyClass.element2
AttributeError: class MyClass has no attribute 'element2'

element1 is bound to the class, element2 is bound to an instance of the class.

How to add/subtract time (hours, minutes, etc.) from a Pandas DataFrame.Index whos objects are of type datetime.time?

This one worked for me:

>> print(df)
                          TotalVolume  Symbol
2016-04-15 09:00:00       108400       2802.T
2016-04-15 09:05:00       50300        2802.T

>> print(df.set_index(pd.to_datetime(df.index.values) - datetime(2016, 4, 15)))

             TotalVolume  Symbol
09:00:00     108400       2802.T
09:05:00     50300        2802.T

What is the correct way to restore a deleted file from SVN?

The problem with doing an svn merge as suggested by Sean Bright is that is reintroduces other changes made in the same revision as the deletion. An svn copy is a more targeted operation that will only affect the deleted files.

Using Tortoise SVN you can resurrect a file that has been deleted from your working copy directory and from later SVN revisions, via a svn copy as follows:

  • Browse to the working copy folder that previously contained the file.
  • Right click on the folder in Explorer, go to TortoiseSVN -> Show log.
  • Right click on the revision number just prior to the revision that deleted the file and select "Browse repository".
  • Right click on the deleted file and select "Copy to working copy..." and save.

The deleted file will now be in the working copy folder. To re-add it back to SVN, right click on the restored file and select SVN Commit.

NB: This method will preserve the previous history of the restored file, however to see the prior history in the TortoiseSVN log you need to make sure "Stop on copy/rename" is unchecked in the Log messages dialog.

How to install Selenium WebDriver on Mac OS

Install

If you use homebrew (which I recommend), you can install selenium using:

brew install selenium-server-standalone

Running

updated -port port_number

To run selenium, do: selenium-server -port 4444

For more options: selenium-server -help

Fade In Fade Out Android Animation in Java

You can also use animationListener, something like this:

fadeIn.setAnimationListener(new AnimationListener() {
    @Override
    public void onAnimationEnd(Animation animation) {
        this.startAnimation(fadeout);
    }
});

How do you create nested dict in Python?

For arbitrary levels of nestedness:

In [2]: def nested_dict():
   ...:     return collections.defaultdict(nested_dict)
   ...:

In [3]: a = nested_dict()

In [4]: a
Out[4]: defaultdict(<function __main__.nested_dict>, {})

In [5]: a['a']['b']['c'] = 1

In [6]: a
Out[6]:
defaultdict(<function __main__.nested_dict>,
            {'a': defaultdict(<function __main__.nested_dict>,
                         {'b': defaultdict(<function __main__.nested_dict>,
                                      {'c': 1})})})

What is the correct way to check for string equality in JavaScript?

If you know they are strings, then there's no need to check for type.

"a" == "b"

However, note that string objects will not be equal.

new String("a") == new String("a")

will return false.

Call the valueOf() method to convert it to a primitive for String objects,

new String("a").valueOf() == new String("a").valueOf()

will return true

What is the purpose of Order By 1 in SQL select statement?

Also see:

http://www.techonthenet.com/sql/order_by.php

For a description of order by. I learned something! :)

I've also used this in the past when I wanted to add an indeterminate number of filters to a sql statement. Sloppy I know, but it worked. :P

RegExp in TypeScript

In typescript, the declaration is something like this:

const regex : RegExp = /.+\*.+/;

using RegExp constructor:

const regex = new RegExp('.+\\*.+');