"test", !! Note that the comparison: (false == 0) evaluates to true and so will any value you set to false as well (without casting).

"\n"; // prints "\n" ?> Why doesn't php -f test.php print TRUE or FALSE? Strings always evaluate to boolean true unless they have a value that's considered "empty" by PHP (taken from the documentation for empty): "" (an empty string); "0" (0 as a string) If you need to set a boolean based on the text value of a string, then you'll need to check for the presence or otherwise of that value. Actually from a complete noob point of view 0 resulting in false makes sense as many languages as I have been taught consider the value 1 as true and the value 0 as false a simple boolean value. Here's how to do it. in Php. Notice what it says at the top of the page: To echo a boolean value, we can use the ternary operator (?) echo también posee una sintaxis abreviada, donde se puede poner el símbolo igual justo después de la etiqueta de apertura de PHP.
var_dump((bool) "1"); //evaluates to true o llame a la función boolval : // ...because this can be used with exactly the same meaning: //array_search returns index of element, and FALSE if nothing is found//but any non-existent element will also remove 'A'! !0, !! Given the following test.php:
Note that the symbolic constants TRUE and FALSE are treated differently. It appears there's a lot more truth in this universe, but false can trump anything that's true...
The value false is not a constant for the number 0, it is a boolean value that indicates false. Antes de PHP 5.4.0, este tipo de sintaxis abreviada únicamente funciona con la opción de configuración short_open_tag activada.

Para convertir un tipo en booleano, puede usar la conversión (bool) o (boolean) antes del tipo. Just a side note, doesn't really matters, the reason -1 is true and not false is because boolean type is treated as unsigned, so -1 would be for example, if it's unsigned int32 translate to hex: 0xFFFFFFFF and back to decimal: 4294967295 which is non-zero.

I was told that this is a feature, not a bug. I believe that the double negation !! I was afraid someone would say this I always try to make something as simple as possible, with as few ifs as possible. The value true is also not a constant for 1, it is a special boolean value that indicates true. falsy, for consistency and to avoid bugs where the programmer believes he got a true …

It is correct that TRUE or FALSE should not be used as constants for the numbers 0 and 1. Los booleanos se pueden usar en sentencias como esta: Debido al hecho de que PHP está escrito de forma débil, si Para evitar esta comparación, puede imponer una comparación sólida utilizando Para convertir un tipo en booleano, puede usar la conversión Conversión booleana a una cadena (tenga en cuenta que Tenga en cuenta que lo contrario también es posible: También todo lo que no sea cero devolverá verdadero: This modified text is an extract of the original Stack Overflow Documentation created by following For those wondering why the string "0" is falsy, consider that a good deal of input data is actually string-typed, even when it is semantically numeral. But there may be times when it might be helpful to see the value of the Boolean as a 1 or 0.

Function to sort array by elements and count of element (before php 5.3) (not use Lambda Functions, and Closures);                                                  Dunno if someone else posted this solution already, but if not, here's a useful and function to convert strings to strict booleans. ""); outputs: boolean true boolean false boolean true boolean false May the life be good to you. More importantly, in the FALSE case, why doesn't it print anything? can perform the same task with the same result if your PHP is not up2date var_dump(! You will have to use an if.

Ah, yes, booleans - bit values that are either set (TRUE) or not set (FALSE). Casting bools to string is not working as maybe expected: When compare with TRUE with also the same string it's also returning true. Just something that will probably save time for many new developers: beware of interpreting FALSE and TRUE as integers.

It just happens to cast to integer 1 when you print it or use it in an expression, but it's not the same as a constant for the integer value 1 and you shouldn't use it as one.

PHP - Get bool to echo false when false. Beware of certain control behavior with boolean and non boolean values :// Consider that the 0 could by any parameters including itself Note you can also use the '!' it's a binary thing. !1, ! Consequently, PHP designers decided to treat 0 and "0" similarly, ie. When compare zero (0) with string it's return true by type jugling.