I want to check whether the &quot;user&quot; key is present or not in the session hash. How can I do this?

Note that I don&#39;t want to check whether the key&#39;s value is nil or not. I just want to check whether the &quot;user&quot; *key* is present.

How to check if a specific key is present in a hash or not?

What is the equivalent of [Python dictionaries][1] but in Bash (should work across OS X and Linux).


  [1]: https://docs.python.org/2/tutorial/datastructures.html#dictionaries

How to define hash tables in Bash?

Suppose I have this code:

    var myArray = new Object();
    myArray[&quot;firstname&quot;] = &quot;Bob&quot;;
    myArray[&quot;lastname&quot;] = &quot;Smith&quot;;
    myArray[&quot;age&quot;] = 25;

Now if I wanted to remove &quot;lastname&quot;?....is there some equivalent of
`myArray[&quot;lastname&quot;].remove()`?

(I need the element gone because the number of elements is important and I want to keep things clean.)


How do I remove objects from a JavaScript associative array?

Based on an associative array in a Bash script, I need to iterate over it to get the key and value.

    #!/bin/bash
    
    declare -A array
    array[foo]=bar
    array[bar]=foo

I actually don&#39;t understand how to get the key while using a for-in loop.

How to iterate over associative arrays in Bash

I have an associative array in the form `key =&gt; value` where key is a numerical value, however it is not a sequential numerical value. The key is actually an ID number and the value is a count. This is fine for most instances, however I want a function that gets the human-readable name of the array and uses that for the key, without changing the value.

I didn&#39;t see a function that does this, but I&#39;m assuming I need to provide the old key and new key (both of which I have) and transform the array. Is there an efficient way of doing this?

In PHP, how do you change the key of an array element?

I have a big dictionary object that has several key value pairs (about 16), but I am only interested in 3 of them. What is the best way (shortest/efficient/most elegant) to achieve that?

The best I know is:

    bigdict = {&#39;a&#39;:1,&#39;b&#39;:2,....,&#39;z&#39;:26} 
    subdict = {&#39;l&#39;:bigdict[&#39;l&#39;], &#39;m&#39;:bigdict[&#39;m&#39;], &#39;n&#39;:bigdict[&#39;n&#39;]}

I am sure there is a more elegant way than this.


Extract subset of key-value pairs from dictionary?

How can I create and fetch associative arrays in Java like I can in PHP?

For example:

    $arr[0][&#39;name&#39;] = &#39;demo&#39;;
    $arr[0][&#39;fname&#39;] = &#39;fdemo&#39;;
    $arr[1][&#39;name&#39;] = &#39;test&#39;;
    $arr[1][&#39;fname&#39;] = &#39;fname&#39;;

Java associative-array

All the documentation I&#39;ve found so far is to update keys that are already created:

     arr[&#39;key&#39;] = val;

I have a string like this: `&quot; name =  oscar &quot; `

And I want to end up with something like this:

    { name: &#39;whatever&#39; }

That is, split the string and get the first element, and then put that in a dictionary.

### Code

    var text = &#39; name = oscar &#39;
    var dict = new Array();
    var keyValuePair = text.split(&#39; = &#39;);
    dict[ keyValuePair[0] ] = &#39;whatever&#39;;
    alert( dict ); // Prints nothing.


Dynamically creating keys in a JavaScript associative array

How do you calculate the union of two `dict` objects in Python, where a `(key, value)` pair is present in the result iff `key` is `in` either dict (unless there are duplicates)?

For example, the union of `{&#39;a&#39; : 0, &#39;b&#39; : 1}` and `{&#39;c&#39; : 2}` is `{&#39;a&#39; : 0, &#39;b&#39; : 1, &#39;c&#39; : 2}`.

Preferably you can do this without modifying either input `dict`. Example of where this is useful: https://stackoverflow.com/questions/1041639/get-a-dict-of-all-variables-currently-in-scope-and-their-values

Union of dict objects in Python

My associative array: 

    $arr = array(
       1 =&gt; &quot;Value1&quot;,
       2 =&gt; &quot;Value2&quot;,
       10 =&gt; &quot;Value10&quot;
    );

Using the following code, `$v` is filled with `$arr`&#39;s values

     foreach($arr as $v){
        echo($v);    // Value1, Value2, Value10
     }

How do I get `$arr`&#39;s keys instead?

     foreach(.....){
        echo($k);    // 1, 2, 10
     }

How to loop through an associative array and get the key?

I am looking for the best way to &quot;add&quot; multiple JavaScript objects (associative arrays).

For example, given:

    a = { &quot;one&quot; : 1, &quot;two&quot; : 2 };
    b = { &quot;three&quot; : 3 };
    c = { &quot;four&quot; : 4, &quot;five&quot; : 5 };

what is the best way to compute:

    { &quot;one&quot; : 1, &quot;two&quot; : 2, &quot;three&quot; : 3, &quot;four&quot; : 4, &quot;five&quot; : 5 }





How to concatenate properties from multiple JavaScript objects

We required a script that simulates Associative arrays or Map like data structure for Shell Scripting, any body?



Associative arrays in Shell scripts

I&#39;m looking for a fast way to turn an associative array in to a string. Typical structure would be like a URL query string but with customizable separators so I can use &#39;`&amp;amp;`&#39; for xhtml links or &#39;`&amp;`&#39; otherwise.

My first inclination is to use `foreach` but since my method could be called many times in one request I fear it might be too slow.

    &lt;?php
    $Amp = $IsXhtml ? &#39;&amp;amp;&#39; : &#39;&amp;&#39;;
    $Parameters = array(&#39;Action&#39; =&gt; &#39;ShowList&#39;, &#39;Page&#39; =&gt; &#39;2&#39;);
    $QueryString = &#39;&#39;;
    foreach ($Parameters as $Key =&gt; $Value)
            $QueryString .= $Amp . $Key . &#39;=&#39; . $Value;

Is there a faster way?

Fastest way to implode an associative array with keys

Is it possible to prepend an associative array with literal key=&gt;value pairs? I know that array_unshift() works with numerical keys, but I&#39;m hoping for something that will work with literal keys.

As an example I&#39;d like to do the following:

    $array1 = array(&#39;fruit3&#39;=&gt;&#39;apple&#39;, &#39;fruit4&#39;=&gt;&#39;orange&#39;);
    $array2 = array(&#39;fruit1&#39;=&gt;&#39;cherry&#39;, &#39;fruit2&#39;=&gt;&#39;blueberry&#39;);

    // prepend magic

    $resulting_array = (&#39;fruit1&#39;=&gt;&#39;cherry&#39;, 
                        &#39;fruit2&#39;=&gt;&#39;blueberry&#39;, 
                        &#39;fruit3&#39;=&gt;&#39;apple&#39;, 
                        &#39;fruit4&#39;=&gt;&#39;orange&#39;);


PHP prepend associative array with literal keys?

When I create a new JavaScript array, and use an integer as a key, each element of that array up to the integer is created as undefined.

For example:

    var test = new Array();
    test[2300] = &#39;Some string&#39;;
    console.log(test);

will output 2298 undefined&#39;s and one &#39;Some string&#39;.

How should I get JavaScript to use 2300 as a string instead of an integer, or how should I keep it from instantiating 2299 empty indices?


Using an integer as a key in an associative array in JavaScript

For example:

    $names = {[bob:27, billy:43, sam:76]};

and then be able to reference it like this:

     $names[bob]

Are there dictionaries in php?

```php
//go through each question
foreach($file_data as $value) {
   //separate the string by pipes and place in variables
   list($category, $question) = explode(&#39;|&#39;, $value);

   //place in assoc array
   $data = array($category =&gt; $question);
   print_r($data);

}
```

This is not working as it replaces the value of data. How can I have it add an associative value each loop though? `$file_data` is an array of data that has a dynamic size.

Adding an item to an associative array

I am trying to create a dictionary of key value pair using Bash script. I am trying using this logic:

    declare -d dictionary
    defaults write &quot;$dictionary&quot; key -string &quot;$value&quot;

...where `$dictionary` is a variable, but this is not working.

Is there a way to create key-value pairs in Bash script?


Is there a way to create key-value pairs in Bash script?

I would like to convert the array:

    Array ( 
    [category] =&gt; category 
    [post_tag] =&gt; post_tag 
    [nav_menu] =&gt; nav_menu 
    [link_category] =&gt; link_category 
    [post_format] =&gt; post_format 
    )

to 

    array(category, post_tag, nav_menu, link_category, post_format)

I tried

    $myarray = &#39;array(&#39;. implode(&#39;, &#39;,get_taxonomies(&#39;&#39;,&#39;names&#39;)) .&#39;)&#39;;

which echos out:

    array(category, post_tag, nav_menu, link_category, post_format)

So I can do 

    echo $myarray;
    echo &#39;array(category, post_tag, nav_menu, link_category, post_format)&#39;;

and it prints the exact same thing.

...but I can&#39;t use `$myarray` in a function in place of the manually entered array because the function doesn&#39;t see it as array or something.

What am I missing here?

Convert an associative array to a simple array of its values in php

I&#39;m trying to store some configuration variables in yaml represented as an associative array aka dictionary.
Here is how I did:

    content_prices:                                                                                                                                                                                                                               
      - {country: AU, price: 6990000}                                                                                                                                                                                                             
      - {country: AT, price: 4990000}                                                                                                                                                                                                             
      - {country: BE, price: 4990000}  
This produce an exception when I try to parse it from my ROR init files:

&gt; undefined method `symbolize_keys!&#39; for nil:NilClass

Here is how I init it:

    Config = YAML.load_file(&quot;#{Rails.root}/config/prices.yml&quot;)[Rails.env].symbolize_keys!

I guess my yaml syntax is wrong, then how to write it properly ?

How to make a list of associative array in yaml

I can&#39;t seem to find the documentation explaining how to create a hash table or associative array in VBA. Is it even possible?

Can you link to an article or better yet post the code?

Hash Table/Associative Array in VBA

    $array1 = array(&quot;$name1&quot; =&gt; &quot;$id1&quot;);
    
    $array2 = array(&quot;$name2&quot; =&gt; &quot;$id2&quot;, &quot;$name3&quot; =&gt; &quot;$id3&quot;);

I need a new array combining all together, i.e. it would be

    $array3 = array(&quot;$name1&quot; =&gt; &quot;$id1&quot;, &quot;$name2&quot; =&gt; &quot;$id2&quot;, &quot;$name3&quot; =&gt; &quot;$id3&quot;);

What is the best way to do this?

Sorry, I forgot, the ids will never match each other, but technically the names could, yet would not be likely, and they all need to be listed in one array.  I looked at array_merge but wasn&#39;t sure if that was best way to do this.  Also, how would you unit test this?

PHP combine two associative arrays into one array

Recently I have read about **hash-tables** in a very famous book &quot;[Introduction to Algorithms][1]&quot;. I haven&#39;t used them in any real applications yet, but want to. But I don&#39;t know how to start.  
Can anyone give me some samples of using it, for example, how to realize a dictionary application (like ABBYY Lingvo) using hash-tables?  
And finally I would like to know what is the difference between hash-tables and associative arrays in PHP, I mean which technology should I use and in which situations?  
If I am wrong (I beg pardon) please correct me, because actually I am starting with hash-tables and I have just basic (theoretical) knowledge about them.  
Thanks a lot.


  [1]: http://www.introductiontoalgorithms.com/

Hash tables VS associative arrays

There is the following query results: (key1 and key2 could be any text)

    id   key1     key2     value

    1    fred     apple    2
    2    mary     orange   10
    3    fred     banana   7
    4    fred     orange   4
    5    sarah    melon    5
    ...


and I wish to store the data in a grid (maybe as an array) **looping** all the records like this:

             apple    orange   banana  melon
    fred        2        4         7     -
    mary        -        10        -     -
    sarah       -        -         -     5


In PHP this would be really easy, using associative arrays:
    
    $result[&#39;fred&#39;][&#39;apple&#39;] = 2;

But in JavaScript associative arrays like this doesn&#39;t work.
After reading tons of tutorial, all I could get was this:

    arr=[];
    arr[1][&#39;apple&#39;] = 2;

but `arr[&#39;fred&#39;][&#39;apple&#39;] = 2;` doesn&#39;t work.
I tried arrays of objects, but objects properties can&#39;t be free text.
The more I was reading tutorials, the more I got confused...

Any idea is welcome :)

Multi-dimensional associative arrays in JavaScript

I&#39;ve written a script that uses associative arrays in bash (v 4).

It works fine on my local machine which is using `4.1.5(1)-release`.

On the production machine, using `4.1.0(1)-release` the following line, which declares the assoc array, fails:


    declare -A uniqjars

with the message:


    /script.sh: line 11: declare: -A: invalid option
    declare: usage: declare [-afFirtx] [-p] [name[=value] ...]


I was under the impression this was a general bash 4 feature?

In the man for bash on the production machine it discusses using `-A` so I assume it *should* work.

&gt; Associative arrays are created using
&gt; &lt;code&gt;declare -A &lt;i&gt;name&lt;/i&gt;&lt;/code&gt;.

I can confirm the script is using the right version of bash by printing out the value of `echo &#39;bash -version`.

What could I be doing wrong?

Associative arrays: error &quot;declare: -A: invalid option&quot;

If I have:

    $array = array( &#39;one&#39; =&gt;&#39;value&#39;, &#39;two&#39; =&gt; &#39;value2&#39; );

how do I get the string `one` back from `$array[1]` ?



php: how to get associative array key from numeric index?

How can I convert a JavaScript associative array into JSON?

I have tried the following:


    var AssocArray = new Array();
    
    AssocArray[&quot;a&quot;] = &quot;The letter A&quot;
    
    console.log(&quot;a = &quot; + AssocArray[&quot;a&quot;]);
    
    // result: &quot;a = The letter A&quot;
    
    JSON.stringify(AssocArray);
    
    // result: &quot;[]&quot;



JavaScript associative array to JSON

I understand that there are no *associative arrays* in JavaScript, only *objects*.

However I can create an *array* with string keys using *bracket notation* like this:

    var myArray = [];
    myArray[&#39;a&#39;] = 200;
    myArray[&#39;b&#39;] = 300;
    console.log(myArray); // Prints [a: 200, b: 300]

So I want to do the exact same thing without using *bracket notation*:

    var myNewArray = [a: 200, b: 300]; // I am getting error - Unexpected token:

This does not work either:

    var myNewArray = [&#39;a&#39;: 200, &#39;b&#39;: 300]; // Same error. Why can I not create?







How to create an associative array in JavaScript literal notation

I do not have a lot of experience with C#, yet I am used of working with associative arrays in PHP.

I see that in C# the List class and the Array are available, but I would like to associate some string keys.

What is the easiest way to handle this?

Thx!

What is the easiest way to handle associative array in c#?

I&#39;ve a following associative array named `$data`

    Array
    (
        [0] =&gt; Array
            (
                [transaction_user_id] =&gt; 359691e27b23f8ef3f8e1c50315cd506
                [transaction_no] =&gt; 19500912050218
                [transaction_total_amount] =&gt; 589.00
                [transaction_date] =&gt; 1335932419
                [transaction_status] =&gt; cancelled
            )
    
        [1] =&gt; Array
            (
                [transaction_user_id] =&gt; 9def02e6337b888d6dbe5617a172c18d
                [transaction_no] =&gt; 36010512050819
                [transaction_total_amount] =&gt; 79.00
                [transaction_date] =&gt; 1336476696
                [transaction_status] =&gt; cancelled
            )
    
        [2] =&gt; Array
            (
                [transaction_user_id] =&gt; 9def02e6337b888d6dbe5617a172c18d
                [transaction_no] =&gt; 19020512050820
                [transaction_total_amount] =&gt; 299.00
                [transaction_date] =&gt; 1336476739
                [transaction_status] =&gt; cancelled
            )
    
        [3] =&gt; Array
            (
                [transaction_user_id] =&gt; 9def02e6337b888d6dbe5617a172c18d
                [transaction_no] =&gt; 27050512050821
                [transaction_total_amount] =&gt; 79.00
                [transaction_date] =&gt; 1336476927
                [transaction_status] =&gt; cancelled
            )
    
        [4] =&gt; Array
            (
                [transaction_user_id] =&gt; 8e9050a3646c98342b9ba079fba80982
                [transaction_no] =&gt; 12070512050822
                [transaction_total_amount] =&gt; 129.00
                [transaction_date] =&gt; 1336477032
                [transaction_status] =&gt; cancelled
            )
    
    )

and I want to convert the value of key `[transaction_date]` into user readable format (i.e. mm/dd/yyyy). For that I written the following code in a function which returns the whole array:

   

     foreach($data as $value)
     {
       	$value[transaction_date]=date(&#39;d/m/Y&#39;,$value[transaction_date]);
     }
        
     return $data;

My problem is I&#39;m getting the same array without changing the value of `[transaction_date]` for all the array elements. Actually array with updated values for `[transaction_date]` is expected to be returned. 
Can anyone help me out to resolve this issue? Thanks in advance.

How to update specific key&#39;s value in an associative array in PHP?

Hi out there in Stackland.  I was wondering if there was either a function or an easy way to change an associative array into an indexed array.

To elaborate, I&#39;m using the Zend framework, and I&#39;ve got a point in my site where I take out a row of an SQL table as an associative array.  I&#39;ve passed it to javascript via an echoed &lt;script&gt; in JSON.  However, I&#39;ve noticed that I can see the names of my database&#39;s columns in Firebug.  Having outsiders know the names of your tables and columns is a big security no-no, so I&#39;d like to change it from 

    SQLarray[user_id]
    SQLarray[block_id]
    SQLarray[b_price] etc.

to

    SQLarray[0]
    SQLarray[1]
    SQLarray[2] etc.

Is there a good way to do this?


It would also work to be able to have a Zend_Table_Abstract-&gt;fetchAll() return a non-associative array, but I don&#39;t think that&#39;s possible.  Thanks for your help!

Change an associative array into an indexed array / get an Zend_Table_Row_Abstract as non-associative

A PHP array can have arrays for its elements. And those arrays can have arrays and so on and so forth. Is there a way to find out the maximum nesting that exists in a PHP array? An example would be a function that returns 1 if the initial array does not have arrays as elements, 2 if at least one element is an array, and so on.

Is there a way to find out how &quot;deep&quot; a PHP array is?

When interpolating PHP&#39;s string-indexed array elements (5.3.3, Win32)
the following behavior may be expected or not:

    $ha = array(&#39;key1&#39; =&gt; &#39;Hello to me&#39;);

    print $ha[&#39;key1&#39;];   # correct (usual way)
    print $ha[key1];     # Warning, works (use of undefined constant)

    print &quot;He said {$ha[&#39;key1&#39;]}&quot;; # correct (usual way)
    print &quot;He said {$ha[key1]}&quot;;   # Warning, works (use of undefined constant)

    print &quot;He said $ha[&#39;key1&#39;]&quot;;   # Error, unexpected T_ENCAPSED_AND_WHITESPACE
    print &quot;He said $ha[ key1 ]&quot;;   # Error, unexpected T_ENCAPSED_AND_WHITESPACE
    print &quot;He said $ha[key1]&quot;;     # !! correct (How Comes?)

Inerestingly, **the last line seems to be correct PHP code**. Any explanations?
Can this feature be trusted?



&lt;hr&gt;
Edit: The point of the posting now set in **bold face** in order to reduce misunderstandings.


Interpolation (double quoted string) of Associative Arrays in PHP

Say that I have an array like the following:

    Array
    (
        [arm] =&gt; Array
            (
                [0] =&gt; A
                [1] =&gt; B
                [2] =&gt; C
            )
        [gender] =&gt; Array
            (
                [0] =&gt; Female
                [1] =&gt; Male
            )
        [location] =&gt; Array
            (
                [0] =&gt; Vancouver
                [1] =&gt; Calgary
            )
    )

How can I find the cartesian product while preserving the keys of the outer associative array and using them in the inner ones? The result of the algorithm should be this:

    Array
    (
        [0] =&gt; Array
            (
                [arm] =&gt; A
                [gender] =&gt; Female
                [location] =&gt; Vancouver
            )
    
        [1] =&gt; Array
            (
                [arm] =&gt; A
                [gender] =&gt; Female
                [location] =&gt; Calgary
            )
    
        [2] =&gt; Array
            (
                [arm] =&gt; A
                [gender] =&gt; Male
                [location] =&gt; Vancouver
            )
    
    ...etc.

I&#39;ve looked up quite a number of cartesian product algorithms but I&#39;m getting stuck on the specifics of how to preserve the associative keys. The current algorithm I am using gives numerical indices only:

        $result = array();
        foreach ($map as $a) {
            if (empty($result)) {
                $result = $a;
                continue;
            }
            $res = array();
            foreach ($result as $r) {
                foreach ($a as $v) {
                    $res[] = array_merge((array)$r, (array)$v);
                }
            }
            $result = $res;
        }
        
        print_r($result);

Any help would be appreciated.

Finding cartesian product with PHP associative arrays

How do you pass an associative array as an argument to a function? Is this possible in Bash?

The code below is not working as expected:

    function iterateArray
    {
    	local ADATA=&quot;${@}&quot;            # associative array
    	
    for key in &quot;${!ADATA[@]}&quot;
    do
    	echo &quot;key - ${key}&quot;
    	echo &quot;value: ${ADATA[$key]}&quot;
    
    done
    
    }

Passing associative arrays to a function like normal arrays does not work:
 
    iterateArray &quot;$A_DATA&quot;

or

    iterateArray &quot;$A_DATA[@]&quot;

How to pass an associative array as argument to a function in Bash?

If you have an associative array:

    Array
    (
        [uid] =&gt; Marvelous
        [status] =&gt; 1
        [set_later] =&gt; Array
            (
                [0] =&gt; 1
                [1] =&gt; 0
            )
    
        [op] =&gt; Submit
        [submit] =&gt; Submit
    )


And you want to access the 2nd item, how would you do it? `$arr[1]` doesn&#39;t seem to be working:

	foreach ($form_state[&#39;values&#39;][&#39;set_later&#39;] as $fieldKey =&gt; $setLater) {
		if (! $setLater) {
			$valueForAll = $form_state[&#39;values&#39;][$fieldKey];
			$_SESSION[SET_NOW_KEY][array_search($valueForAll, $form_state[&#39;values&#39;])] = $valueForAll; // this isn&#39;t getting the value properly
		}
	}

This code is supposed to produce:

    $_SESSION[SET_NOW_KEY][&#39;status&#39;] = 1

But it just produces a blank entry.

 

PHP: Get n-th item of an associative array

Example:

    list($fruit1, $fruit2) = array(&#39;apples&#39;, &#39;oranges&#39;);

code above of course works ok, but code below:

    list($fruit1, $fruit2) = array(&#39;fruit1&#39; =&gt; &#39;apples&#39;, &#39;fruit2&#39; =&gt; &#39;oranges&#39;);

gives: `Notice: Undefined offset: 1 in....`

Is there any way to refer to named keys somehow with list like `list(&#39;fruit1&#39; : $fruit1)`, have you seen anything like this planned for future release?

Can PHP&#39;s list() work with associative arrays?

I am implementing a way to transfer a set of data to a programmable dongle. The dongle is based on a smart card technology and can execute an arbitrary code inside. The input and output data is passed as a binary blocks that can be accessed via input and output pointers.

I would like to use an associative array to simplify the data processing code. Everything should work this way:

First the host application:

    // Host application in C++
    in_data[&quot;method&quot;] = &quot;calc_r&quot;;
    in_data[&quot;id&quot;] = 12;
    in_data[&quot;loc_a&quot;] = 56.19;
    in_data[&quot;loc_l&quot;] = 44.02;
    processor-&gt;send(in_data);

Next the code inside the dongle:

    // Some dongle function in C
    char* method_name = assoc_get_string(in_data, &quot;method&quot;);
    int id = assoc_get_int(in_data, &quot;id&quot;);
    float loc_a = assoc_get_float(in_data, &quot;loc_a&quot;);
    float loc_l = assoc_get_float(in_data, &quot;loc_l&quot;);

So my question is about the dongle part functionality. Is there C code or library to implement such an associative array behavior like the above?

All Associative Array Solutions on Gang of Coders

Total of 38 Associative Array Solutions