PHP string with int or float to number - php

Question

If I have two strings in an array:
$x = array("int(100)", "float(2.1)");
is there a simple way of reading each value as the number stored inside as a number?
The reason is I am looking at a function (not mine) that sometimes receives an int and sometimes a float. I cannot control the data it receives.
function convertAlpha($AlphaValue) {
return((127/100)*(100-$AlphaValue));
}
It causes an error in php
PHP Notice: A non well formed numeric value encountered
which I want to get rid of.
I could strip the string down and see what it is and do an intval/floatval but wondered if there was a neat way.
UPDATE:
Playing about a bit I have this:
function convertAlpha($AlphaValue)
{
$x = explode("(", $AlphaValue);
$y = explode(")", $x[1]);
if ($x[0] == "int") {
$z = intval($y[0]);
}
if ($x[0] == "float") {
$z = floatval($y[0]);
}
return((127/100)*(100-$z)); }
This which works but it just messy.

Answer 1

<?php
$x = array("int(100)", "float(2.1)");
$result = [];
foreach($x as $each_value){
$matches = [];
if(preg_match('/^([a-z]+)(\((\d+(\.\d+)?)\))$/',$each_value,$matches)){
switch($matches[1]){
case "int": $result[] = intval($matches[3]); break;
case "float": $result[] = floatval($matches[3]);
}
}
}
print_r($result);
OUTPUT
Array
(
[0] => 100
[1] => 2.1
)

Answer 2

The simplest would simply be to make the array as you need it, so instead of
$x = array("int(100)", "float(2.1)");
you have:
$x = [100, 2.1];
but as this is not what you want you got two choices now. One, is to use eval(), for example:
$x = ['(int)100', '(float)2.1'];
foreach ($x as $v) {
var_dump(eval("return ${v};"));
}
which will produce:
int(100)
double(2.1)
As you noticed, source array is bit different because as there is no such function in PHP as int() or float(), so if you decide to use eval() you need to change the string to be valid PHP code with the casting as shown in above example, or with use of existing intval() or floatval() functions. Finally, you can parse strings yourself (most likely with preg_match()), check for your own syntax and either convert to PHP to eval() it or just process it in your own code, which usually is recommended over using eval().

Answer 3

The way I would do it is by using a regex to determine the type and value by 2 seperate groups:
([a-z]+)\((\d*\.?\d*)\)
The regex captures the alphanumeric characters up and until the first (. It then looks for the characters between the ( and ) with this part: \d*\.?\d*.
The digit-part of the regex accepts input like: 12.34, .12, 12. and 123
$re = '/([a-z]+)\((\d*\.?\d*)\)/m';
$input_values = array('int(100)', 'float(2.1)');
foreach($input_values as $input) {
preg_match_all($re, $input, $matches, PREG_SET_ORDER, 0);
var_dump($matches);
}
Which leads to the output below. As you can see, there is the type in the [1] slot and the number in the [2] slot of the array
array(1) {
[0]=>
array(3) {
[0]=>
string(8) "int(100)"
[1]=>
string(3) "int"
[2]=>
string(3) "100"
}
}
array(1) {
[0]=>
array(3) {
[0]=>
string(10) "float(2.1)"
[1]=>
string(5) "float"
[2]=>
string(3) "2.1"
}
}
You can then use a check to perform the casting like:
$value;
if(matches[1] === "int") {
$value = intval($matches[2]);
} elseif (matches[1] === "float") {
$value = floatval($matches[2]);
}
The latter code still needs error handling, but you get the idea. Hope this helps!

Answer 4

PHP is historically typed against strings so it's pretty strong with cases like these.
$x = array("int(100)", "float(2.1)");
^^^ ^^^
You can actually turn each of those strings into a number by multiplying the substring starting after the first "(" with just one to turn it into a number - be it integer or float:
$numbers = array_map(function($string) {
return 1 * substr(strstr($string, '('), 1);
}, $x);
var_dump($numbers);
array(2) {
[0] =>
int(100)
[1] =>
double(2.1)
}
That is PHP takes everthing numberish from a string until that string seems to end and will calculate it into either an integer or float (var_dump() shows float as double). It's just consuming all number parts from the beginning of the string.
Not saying existing answers are wrong per-se, but if you ask that as a PHP question, PHP has a parser very well for that. My suggestion is to just remove the superfluous information from the beginning of the string and let PHP do the rest.
If you want it more precise, regular expressions are most likely your friend as in the yet top rated answer, still combined with PHP will give you full checks on each string:
$numbers = array_map(function($string) {
$result = preg_match('~^(?:int|float)\(([^)]+)\)$~', $string, $group) ? $group[1] : null;
return null === $result ? $result : 1 * $result;
}, $x);
So all non int and float strings will be turned into NULLs (if any).