&& and || conditions in single IF Condition in PHP

Question

I want to check whether the length of $a is 0 or if the length is not 0 then check if it is a numeric value in single IF statement in PHP. I tried this but not working

$a = '23bc';
if((strlen($a)===0 || (strlen($a)>0 && ctype_digit($a))) )
{
    echo 'Good to Go';
}
else
{
    echo 'Bad to Go';
}

I do not want to apply nested conditions here. Is it possible to do it in single IF statement?

I found this question here but this does not answers what I am asking for && (AND) and || (OR) in IF statements

No I want to check if $a has a length of 0 or if it is not 0 then check if it is numeric — NoOneSeesMe, Dec 06 '14 at 21:07
Looks like it works to me: "bad to go" because it's length greater than 0 but not all numeric — Mark Baker, Dec 06 '14 at 21:07
*" I tried this but not working"* What exactly is not working? What did you get and what did you expect (and why)? — Felix Kling, Dec 06 '14 at 21:07
Are you aware of what ctype_digit checks? It will return false if you pass 0 as an integer. If you want integers to pass the test you have to use is_numeric, as ctype_digit will interpret any integers as ASCII codes. — Œlrim, Dec 06 '14 at 21:10
@Rizier123 did you try the whole code I have provided there? — NoOneSeesMe, Dec 06 '14 at 21:17
@oelrim is_numberic will also let 0.0 as numeric while I want to be number only — NoOneSeesMe, Dec 06 '14 at 21:19
@oelrim after your comment I tried ctype_digit giving $a='0'; and it correctly checked it. — NoOneSeesMe, Dec 06 '14 at 21:20
@NoOneSeesMe ctype_digit(0) returns false for me, whereas ctype_digit('0') returns true. — Œlrim, Dec 06 '14 at 21:26

slevy1 · Answer 1 · 2014-12-07T01:11:26.467

It would be nice to know what your script is trying to achieve beyond using a one-liner in an if conditional concerning an empty string or a numeric string. With cytpe_digit() every character must evaluate as a number to qualify as a numeric string. You get a false result with '23bc' because of the 'bc' portion.

One of the problematic aspects with the script is that one don't know which condition results in a true. One or the other conditions could be true or they could both be false.
See demo: http://3v4l.org/8Pchk.

You could rewrite the code making use of a ternary expression to have a one liner which eliminates the if-else construct, as follows:

<?php
$a = '23bc';

if( strlen( $a ) != 0) {
    echo ctype_digit( $a )? "Good to Go\n"  :  "Bad to Go\n";
}

The following may be more in line with what you're asking. Here's the ultimate one-liner:

<?php
echo ( !strlen($a) || ctype_digit($a) )? "Good to Go\n"  :  "Bad to Go\n";

Because of the strictness of the identity operator === if $a is null, then you you'll see "Bad to Go. You may either test for equality strlen($a) == 0 or you can be more succinct by using the ! operator (boolean NOT). See demo: http://3v4l.org/7cfV0

&& and || conditions in single IF Condition in PHP

1 Answers1