I saw in the PHP documentation that there is a function called floatval() , to get the floating-point value of a variable. So I saw on the internet a question similar to that on the internet:
$value = '152a.35678';
$value = floatval($value);
echo $value;
What is the value that will be printed? Because? Could you tell me more about this function, and about float ?
Retrieved from tag float :
Float is an abbreviation for Floating Point Number (Floating Point Number). And in most programming languages, this type is used for variables with decimal values such as
0.1or15.0025.
In PHP there is a reliability problem of floating points:
Floating-point numbers have Limited precision ... Uncommon mathematical operations may cause major errors, and of course error propagation must be considered when multiple operations are performed made ... So, never rely on results with floating-point numbers to the last house, and never compare floating-point numbers in equalities .
So be careful when using them, whatever your purpose. There are more in-depth questions that take you deeper into this subject that you can find here and here too .
The PHP floatval () function, as explained in documentation , gets the floating-point value of a given variable. And in this case:
$value = '152a.35678';
$value = floatval($value);
echo $value; //imprime 152
It will output 152 . By analyzing with var_dump() , you can see that the variable is of type float , with value of 152 .
The floatval() function receives a single parameter, which is the value you want to get it from the floating point.
float floatval ( mixed $var )
If you put letters (applicable to the string in general), on the left will be returned 0 .
$var = 'The122.34343';
$float_value_of_var = floatval($var);
echo $float_value_of_var; // imprime 0
But if you add in the end, it will try to apply, the general rule for conversion to floating point .
$variavel = '122.34343The';
$valor_float = floatval ($variavel);
echo $valor_float; // imprime 122.34343
On type conversion, PHP usually already does this for you. That's why you can:
- Write a
intand access it as if it were a pointer.- Write a
floatand access it as aint. It is certain that the result will be catastrophic in this case, but it is possible.- Get a 0 and be considered false or other numbers (no matter what type) be interpreted as true in operations that require a Boolean.
- Write two
shortin sequence and read as aint. Probably nothing useful will be achieved but it is possible.- Record "SOpt" and read this as a
int, I do not know why.
PHP, which is a weakly typed language, allows this. You can read more about strong typing and weak here .