PHP: If statement returns True instead of False

Question

I have an array called as myArr. It contains strings and integers, e.g.

0  st ts 0  0
st 0  0  0  0

For debugging the php script, I'm using Zend Studio. The debug window says that a cell [0][0] contains int 0. BUT the problem is that IF statement returns TRUE.

        for ($i = 0; $i < $rows; $i++) {
          for ($j = 0; $j < $cols; $j++) {
            if ($myArr[$i][$j] == 'ts' || $myArr[$i][$j] == 'st') {
                $num++;
            }
          }
        }

UPDATE: I'm running the code in Debug mode in Zend Studio. So, I can see that $num is increasing in each iteration. Also, I can see that cursor goes inside the loop

@rudi_visser: I'm runnign the code in Debug mode. So, I can see that $num is increasing in each iteration. Also, I can see that cursor goes inside the loop. — Gusgus
– Gusgus, Commented May 29, 2012 at 22:36
There is no such thing as "Debug mode" in the context of the real PHP parser. What is the actual output of PHP when executing directly? Ignore Zend Studio for now. — Rudi Visser
– Rudi Visser, Commented May 29, 2012 at 22:36
@rudi_visser: it is a debug mode, when you may doing everything debug mode is implying — zerkms
– zerkms, Commented May 29, 2012 at 22:41

nickb · Accepted Answer · 2012-05-29 22:37:27Z

8

Because 0 == 'ts' is true. You need to use the equality comparison ===. Otherwise, PHP's type juggling causes this statement to evaluate to true.

See this demo to show why the if statement is evaluating to true.

answered May 29, 2012 at 22:37

nickb

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kapa · Accepted Answer · 2012-05-29 23:05:22Z

5

When a string is compared to an integer, the string will be converted to an integer automatically and in your case the string has no digits so it will be evaluated to zero leading to satisfy the equality, you have two options:

if ('0' == 'tr')

OR

if (0 === 'tr')

were the === means check for the value and type.

I also found this helpful for you from the PHP manual:

The value is given by the initial portion of the string. If the string starts with valid numeric data, this will be the value used. Otherwise, the value will be 0 (zero)

edited May 29, 2012 at 23:05

kapa

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answered May 29, 2012 at 22:39

Ahmed Jolani

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Comments

Dan Dumitriu · Accepted Answer · 2012-05-29 22:39:43Z

-2

any string compared to 0 it's true

answered May 29, 2012 at 22:39

Dan Dumitriu

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