strange question about PHP convert string to int

Question

im trying to convert string to integer but return 0 or wrong number. Below is the code i have tested. Anyone know why? Thanks

<?php
echo gettype(0x55)."\n"; //type is integer
echo 0x55."\n"; //this is correct
echo (int)"0x55"."\n"; //why 0?
echo intval("0x55"); //why 0?

return

integer 85 0 0

because the string has a 0 before it has any Non-Numeric (the x) which terminates the cast, or intval() as its not a numeric — RiggsFolly
– RiggsFolly, Commented Jan 4, 2022 at 17:25
If you can post an actual code sample with the literal string you're trying to convert we can probably give you a more useful answer than "well I guess don't do that". — Sammitch
– Sammitch, Commented Jan 4, 2022 at 17:27
If you want the decimal value of a hexadecimal string, use hexdec. But remove the "0x" first. — KompjoeFriek
– KompjoeFriek, Commented Jan 4, 2022 at 17:27
Simple test, run echo (int)"3x55"."\n"; and you will get 3 — RiggsFolly
– RiggsFolly, Commented Jan 4, 2022 at 17:27
Also see php.net/manual/en/… and php.net/manual/en/language.types.numeric-strings.php — The fourth bird
– The fourth bird, Commented Jan 4, 2022 at 17:31

Barmar · Accepted Answer · 2022-01-04 17:28:01Z

2

By default, intval() parses base 10, so it ignores the 0x prefix.

If you specify the base as 0, it will determine the base dynamically from the string prefix: 0x means hex, 0 means octal.

So use intval("0x55", 0).

I don't think there's any equivalent for the typecast syntax (int).

answered Jan 4, 2022 at 17:28

Barmar

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