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Exchange array keys \ values

Exchange keys with values and vice-versa from an associative array can be a very common problem. Let's how we can solve it:

PHP: Using the array_flip function

This native function will do the job on the fly!

var_dump( array_flip( array('a', 'b', 'c') )  );

Javascript: using an underscore.js method

If you use underscore.js, you have the invert method.

_.invert([1, 2]);

Javascript: building a new array

We can easily build a function to emulate the PHP array_flip function

function array_flip(trans)
   var key, tmp_ar = {};
   for ( key in trans )
       if ( trans.hasOwnProperty( key ) )
           tmp_ar[trans[key]] = key;
   return tmp_ar;

Python: using a dictionary structure

There's a good way to create an associative array and exchange values with Python using the dictionary structure.

a = dict()
a['one'] = 1
a['two'] = 2
res = dict((v,k) for k,v in a.iteritems())
print res