php if inside foreach wrong

Question

I have a problem with if inside foreach. The answer for code must be “Equal” but is “EqualEqual”.

Here is my code

$list=array(
    "X"     => "X",
    "0"     => "0",
    "2"     => "2",
    "3"     => "3"
);

$var="X";

foreach ($list as $key =>  $val){

    if ($var==$key) {
        echo 'Equal';        
    }

}

Wants to know why the result comes out EqualEqual, there's only one array element with the key "X" so, it should be Equal. — tbddeveloper
– tbddeveloper, Commented Jul 31, 2014 at 12:12
It's printing out Equal for "X" == "0" as well as for "X" == "X" - FYI — Jonathon
– Jonathon, Commented Jul 31, 2014 at 12:15

t3chguy · Accepted Answer · 2014-07-31 12:12:46Z

6

Use:

if ($var===$key) {
    echo 'Equal';        
}

You need === because var_dump($var==0); returns true, which is after type juggling.

answered Jul 31, 2014 at 12:12

t3chguy

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9 Comments

t3chguy Over a year ago

Why downvote? My answer does as the OP wants and is functional.

tbddeveloper Over a year ago

it's the answer, but explain why it's the answer. ( I didn't downvote)

t3chguy Over a year ago

Sometimes type juggling is really counter-intuitive

Daryl Gill Over a year ago

For clarification the == is a loose comparison syntax, it it will cast the variable to multiple types "type juggling" so if your comparing (int) 1 to (string) 1 you will get a true return. Using the === operator will not type juggle but will return an exact match. Comparing (int) 1 to (string) 1 will return false

Daryl Gill Over a year ago

So using === when comparing strings is recommended. Highly

|

Sougata Bose · Accepted Answer · 2014-07-31 12:50:50Z

1

var_dump('X' == 0);//true

reference - http://php.net/manual/en/language.operators.comparison.php

var_dump(0 == "a"); // 0 == 0 -> true
var_dump("1" == "01"); // 1 == 1 -> true
var_dump("10" == "1e1"); // 10 == 10 -> true
var_dump(100 == "1e2"); // 100 == 100 -> true

If you compare a number with a string or the comparison involves numerical strings, then each string is converted to a number and the comparison performed numerically. These rules also apply to the switch statement. The type conversion does not take place when the comparison is === or !== as this involves comparing the type as well as the value.

$a == $b    Equal   TRUE if $a is equal to $b after type juggling.
$a === $b   Identical   TRUE if $a is equal to $b, and they are of the same type.

so, try to use "===" instead of "==".

answered Jul 31, 2014 at 12:50

Sougata Bose

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2 Comments

user3895472 Over a year ago

Yes, but "===" not working if $var come from a $_GET variable

Sougata Bose Over a year ago

if form get, the same is happening?

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