case 1:
echo false . 'test';
output:
test
case 2:
echo true . 'test';
output:
1test
Why true cast to 1 but false nothing?
views:
82answers:
1
+3
A:
Simple:
A value can be converted to a string using the
(string)cast or thestrval()function. String conversion is automatically done in the scope of an expression where a string is needed. This happens when using theecho()orprint()functions, or when a variable is compared to a string.A boolean TRUE value is converted to the string
"1". Boolean FALSE is converted to""(the empty string). This allows conversion back and forth between boolean and string values.
http://php.net/manual/en/language.types.string.php#language.types.string.casting
deceze
2010-05-06 06:18:11
If I had one complaint about PHP, it would be that anytime something goes wrong it simply disappears quietly. Why can't everything just blow up in a catastrophic explosion like C++?
Lotus Notes
2010-05-06 06:22:18
@Byron activate error handling
OM The Eternity
2010-05-06 06:23:45
@Byron I don't know what's supposed to be "wrong" here. It's simply weak typing and type juggling in action. Learn the conversion rules, they are part of the basics of PHP and pretty simple.
deceze
2010-05-06 06:24:35
@OM The Eternity I always keep it on E_ALL | E_STRICT. What I meant was that it's more difficult to visually pinpoint where the string disappeared when echoing out variables for testing. @deceze, yes I'm thankful for empty strings evaluating to false so that we don't have to check $_POST values as being == '' and can just use the boolean.
Lotus Notes
2010-05-06 06:27:59
@Deceze thanks for pointing me where I was wrong... Will keep that in my knowledge.. Thanks again...
OM The Eternity
2010-05-06 06:32:22
For everyone confused about type juggling, start here: http://php.net/manual/en/language.types.type-juggling.php
deceze
2010-05-06 06:34:07