Given a string variable (form input), how can I determine whether it
represents a valid integer?
is_numeric is true for floats as well as integers, and is_int always
fails on a string.
P. 6 6651
Paul E Collins wrote: Given a string variable (form input), how can I determine whether it represents a valid integer?
is_numeric is true for floats as well as integers, and is_int always fails on a string.
P.
intval( $string ) == $string
works for me...
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From listening comes wisdom and from speaking repentance.
"Paul E Collins" <fi************ ******@CL4.org> wrote: Given a string variable (form input), how can I determine whether it represents a valid integer?
Okay, I've come up with a solution:
function isInteger($x)
{
return ($x === (string) (int) $x);
}
It returns false if $x has leading zeros, but that doesn't matter for
my purposes.
P.
Rutger Claes wrote: Paul E Collins wrote:
Given a string variable (form input), how can I determine whether it represents a valid integer?
is_numeric is true for floats as well as integers, and is_int always fails on a string.
intval( $string ) == $string
works for me...
Depends on how strict you need to be...
intval($n)==$n will return TRUE if you have a float like 5.0
However, if you use:
intval($n)===$n
Then the string '5' would fail...
If you need to reject floats, but need to use strings as well, you'll
really need to do something like this (pulled from something I did a
couple years ago):
/**
* input_intval
*
* Takes a variable and returns the integer value that corresponds
* to the value. If the value cannot be represented by an integer,
* FALSE is returned.
*
* @param $n [mixed] Value to check.
* @result Returns an integer value or FALSE. Check for FALSE using
* if(input_intval ($n)===FALSE) in case of integer < 0 being
* returned.
**/
function input_intval($n ){
if(is_numeric($ n)){
if(is_int($n)){
return $n;
}else{
// this is a float...
if(intval($n)== $n){
return $n;
}else{
return FALSE;
}
}
}else{
return FALSE;
}
}
--
Justin Koivisto - sp**@koivi.com http://www.koivi.com
Justin Koivisto wrote: Rutger Claes wrote:
Paul E Collins wrote:
Given a string variable (form input), how can I determine whether it represents a valid integer?
is_numeric is true for floats as well as integers, and is_int always fails on a string.
intval( $string ) == $string
works for me...
Depends on how strict you need to be...
intval($n)==$n will return TRUE if you have a float like 5.0
However, if you use:
intval($n)===$n
Then the string '5' would fail...
If you need to reject floats, but need to use strings as well, you'll really need to do something like this (pulled from something I did a couple years ago):
/** * input_intval * * Takes a variable and returns the integer value that corresponds * to the value. If the value cannot be represented by an integer, * FALSE is returned. * * @param $n [mixed] Value to check. * @result Returns an integer value or FALSE. Check for FALSE using * if(input_intval ($n)===FALSE) in case of integer < 0 being * returned. **/ function input_intval($n ){ if(is_numeric($ n)){ if(is_int($n)){ return $n; }else{ // this is a float... if(intval($n)== $n){ return $n;
Sorry, that should have been:
return intval($n);
I was getting too far ahead of myself typing it out...
}else{ return FALSE; } } }else{ return FALSE; } }
--
Justin Koivisto - sp**@koivi.com http://www.koivi.com
Here is the code I use:
$integer = (int)$value;
if ((string)$value <> (string)$intege r) {
$this->errors[$field] = "Value is not an integer";
return $value;
} // if
--
Tony Marston http://www.tonymarston.net
"Paul E Collins" <fi************ ******@CL4.org> wrote in message
news:cn******** **@titan.btinte rnet.com... Given a string variable (form input), how can I determine whether it represents a valid integer?
is_numeric is true for floats as well as integers, and is_int always fails on a string.
P.
Paul E Collins wrote: Given a string variable (form input), how can I determine whether it represents a valid integer?
is_numeric is true for floats as well as integers, and is_int always fails on a string.
P.
"Zero" sensitive function :) 5.0000 is integer 5.0001 is not...
<?php
function checkInteger($i nput) {
// Check type
if(is_integer($ input)) {
return true;
} // if
// Typecast
$in = (integer) $input;
// Check strlen
if(($in == $input) && (strlen($in) == strlen($input)) ) {
return true;
// No '.'?
} elseif(strpos($ input, '.') === false) {
return false;
// We have '.'
} else {
// One for dot, other for zeros
$dig_num = strlen($input) - strlen($in) - 1;
// Get zeros
$zeros = '.';
for($i = 0; $i < $dig_num; $i++) {
$zeros .= '0';
} // form
// Final check
return (string) $in . $zeros == $input ? true : false;
} // if
} // func checkInteger
// Test it with this code!
print checkInteger('5 .00000') ? 'OK, int' : 'Not OK';
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