PHP reads 1.10 value as 1.1 (0 at end of variable not honored)

This is hard for me to word, but easier for me to demonstrate:

I have a select option:

<option <?php if($frequency[$key]=='1.10'){echo "selected";}?> value='1.10'>1 every 10 days</option>

Really, $frequency[$key]=1.1; , but the above still shows up sele开发者_如何学编程cted. I've never seen this before, and didnt know it could happen. Any ideas on how to prevent this?

Working with php5. Thank you, Hudson

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It's because PHP likes numbers so much that if either side of the comparison looks like a number, it'll try to make both operands numbers. This means your string gets casted to a float, and, indeed, becomes 1.1.

To compare strings and make sure they're compared as strings, either use === (assuming your other operand is also a string), or use strcmp.

if ($frenquency[$key] === '1.10')
if (strcmp($frenquency[$key], '1.10') == 0)

For more information, see the PHP manual on the Comparison Operators, page section 'Comparison with various types'.

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You need to use the identity comparator ===, not the equality comparator ==.

$f = 1.1;
$s = '1.10';

$s == $f;  // true
$s === $f; // false

Or, you could do an explicit string comparison:

strcmp($s, $f);  // int(-1) -- they are not equal

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Just an idea, but try "===" instead of "==" when you do the comparison, and put double quotes around 1.10 to force type as a string.

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The manual tends to be pretty harsh when it comes to comparing floats. You should compare them as a string if you want a distinction between 1.1 and 1.10.