PHP code aposthropy problem what does it mean “”

I cannot understand the section $type = '';
The question is:
what does $type = ''; mean?, particularly apostrophes,
This is the function which writes out the types of variables.

$type = ''

$type = '';

<?php

function what_type($variable)

$type = '';
if (is_integer($variable)) $type .= 'integer, '; else
if (is_float($variable)) $type .= 'float, '; else
if (is_string($variable)) $type .= 'string, ';
if (is_numeric($variable))
$type .= "and is_numeric($variable) === true";
echo $type.'<br />';


$a = 7;
$b = 3.25;
$c = 'some code';
$d = '55';

echo '$a the value of 7 is the type of '; what_type($a);
echo '$b the value of 3.25 is the type of '; what_type($b);
echo '$c the value of ' . "'some code'" . ' is the type of ';
what_type($c);
echo '$d the value of ' . "'55'" . ' is the type of '; what_type($d);
?>


$type

2 Answers
2

$type = '';


This simply initializes the variable $type to an empty string. This is not explicitly needed because PHP defaults undeclared variables to empty values. However, if you do not initialize the variable, and then later try to change it:

$type

$type = $type . 'integer, ';


Or use it:

echo $type;


Then you'll get a warning from PHP that you're trying to change a variable that doesn't exist. Thus, setting the variable to an empty blank string is a common way to avoid that warning.

here $type = '' is a default value for the $type variable.
In you example

$type = ''

$type

if (is_integer($variable)) $type .= 'integer, '; else
if (is_float($variable)) $type .= 'float, '; else
if (is_string($variable)) $type .= 'string, ';
if (is_numeric($variable))
$type .= "oraz is_numeric($variable) === true";


You set $type variable only if at least one of four if will be true.
For example if $variable is bool type you wont set $type variable and get undefined variable error that`s why you need to set some default value for variable to be sure that this variable will exist for sure.

$type

if

$variable

$type

Required, but never shown

Required, but never shown

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