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PYTHON create_function
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Python replacement for PHP's create_function
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>>> def make_incrementor(n): ... return lambda x: x + n ... >>> f = make_incrementor(42) >>> f(0) 42 >>> f(1) 43 create_function(PHP 4 >= 4.0.1, PHP 5) create_function — Create an anonymous (lambda-style) function Description
string create_function
( string $args
, string $code
)
Creates an anonymous function from the parameters passed, and returns a unique name for it. ParametersUsually these parameters will be passed as single quote delimited strings. The reason for using single quoted strings, is to protect the variable names from parsing, otherwise, if you use double quotes there will be a need to escape the variable names, e.g. \$avar.
Return ValuesReturns a unique function name as a string, or FALSE on error. Examples
Example #1 Creating an anonymous function with create_function() You can use this function, to (for example) create a function from information gathered at run time:
<?php
Or, perhaps to have general handler function that can apply a set of operations to a list of parameters:
Example #2 Making a general processing function with create_function()
<?php The above example will output: Using the first array of anonymous functions parameters: 2.3445, M_PI some trig: -1.6291725057799 a hypotenuse: 3.9199852871011 b*a^2 = 4.8103313314525 min(b^2+a, a^2,b) = 8.6382729035898 ln(a/b) = 0.27122299212594 Using the second array of anonymous functions ** "Twas the night" and "Twas brilling and the slithy toves" ** Look the same to me! (looking at the first 3 chars) CRCs: -725381282 , 1908338681 similar(a,b) = 11(45.833333333333%)
But perhaps the most common use for of lambda-style (anonymous) functions is to create callback functions, for example when using array_walk() or usort()
Example #3 Using anonymous functions as callback functions
<?php The above example will output: Array ( [0] => the mango [1] => a mango [2] => that mango [3] => this mango ) an array of strings ordered from shorter to longer
<?php The above example will output: Array ( [0] => small [1] => larger [2] => a big string [3] => it is a string thing ) sort it from longer to shorter
<?php The above example will output: Array ( [0] => it is a string thing [1] => a big string [2] => larger [3] => small )
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