PHP - Introduction Type juggling


Let's check another piece of code:


     $a = "1"; /*w w  w. j a v  a 2 s. c o m*/
     $b = 2; 
     var_dump($a + $b); // 3 
     var_dump($a . $b); // 12 


The + operator returns the sum of two numeric values.

The . operator concatenates two strings.

Thus, the preceding code assigns a string and an integer to two variables, and then tries to add and concatenate them.

When trying to add them using +, PHP needs two numeric values, and so it tries to adapt the string to an integer.

In this case, the string represents a valid number.

That is the reason why we see the first result as an integer 3 (1 + 2).

In the last line, we are performing a string concatenation.

We have an integer in $b, so PHP will first try to convert it to a string-which is "2" and then concatenate it with the other string, "1".

The result is the string "12".

Type juggling

PHP tries to convert the data type of a variable when needed.

PHP does not change the value and type of the variable itself.

It will take the value and try to transform it, leaving the variable intact.

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