PHP: Variable in a function name

Question

I want to trigger a function based on a variable.

function sound_dog() { return \'woof\'; }
function sound_cow() { return \'moo\'; }

$animal = \'cow\';
print soun         


        

Answer 1

You can use curly brackets to build your function name. Not sure of backwards compatibility, but at least PHP 7+ can do it.

Here is my code when using Carbon to add or subtract time based on user chosen type (of 'add' or 'sub'):

$type = $this->date->calculation_type; // 'add' or 'sub'

$result = $this->contactFields[$this->date->{'base_date_field'}]
                   ->{$type.'Years'}( $this->date->{'calculation_years'} )
                   ->{$type.'Months'}( $this->date->{'calculation_months'} )
                   ->{$type.'Weeks'}( $this->date->{'calculation_weeks'} )
                   ->{$type.'Days'}( $this->date->{'calculation_days'} );

The important part here is the {$type.'someString'} sections. This will generate the function name before executing it. So in the first case if the user has chosen 'add', {$type.'Years'} becomes addYears.