CODEWITHSUNDEEP
phptrailing
Mouna Cheikhna
Mouna Cheikhna

Reputation: 39628

Remove all 0s except trailing 0s from a string

There are a lot of questions on removing leading and trailing 0s but i couldn't find a way to remove all 0s except trailing 0s (leading 0 or in any other place other than the end).

100010 -> 110  
010200 -> 1200  
01110  -> 1110

any suggestions ?

Upvotes: 0

Views: 193

Answers (8)

hakre
hakre

Reputation: 197775

You want to replace all zeroes that are not at the end of the string.

You can do that with a little regular expressions with a so called negative look-ahead, so only zeros match to be replaced that are not at the end of the string:

$actual = preg_replace('/0+(?!$|0)/', '', $subject);

The $ symbolizes the end of a string. 0+ means one or more zeroes. And that is greedy, meaning, if there are two, it will take two, not one. That is important to not replace at the end. But also it needs to be written, that no 0 is allowed to follow for what is being replaced.

Quite like you formulated your sentence:

a way to remove all 0s except trailing 0s (leading 0 or in any other place other than the end).

That is: 0+(?!$|0). See http://www.regular-expressions.info/lookaround.html - Demo.

The other variant would be with atomic grouping, which should be a little bit more straight forward (Demo):

(?>0+)(?!$)

Upvotes: 1

lafor
lafor

Reputation: 12776

You can use regexes to do what you want: 

if(preg_match('/^(0*)(.*?)(0*)$/',$string,$match)) {
    $string = $match[1] . str_replace('0','',$match[2]) . $match[3];
}

Upvotes: 0

István Őri
István Őri

Reputation: 288

here is a solution. there shoud be prettier one, but that works also.

$subject = "010200";
$match = array();
preg_match("/0*$/",$subject,$match);
echo preg_replace("/0*/","",$subject).$match[0];

Upvotes: 0

Yuriy
Yuriy

Reputation: 1984

// original string
$string = '100010';

// remember trailing zeros, if any
$trailing_zeros = '';
if (preg_match('/(0+)$/', $string, $matches)) {
    $trailing_zeros = $matches[1];
}

// remove all zeros
$string = str_replace('0', '', $string);
// add trailing ones back, if they were found before
$string .= $trailing_zeros;

Upvotes: 0

Brent Baisley
Brent Baisley

Reputation: 12721

You can use regex as others suggested, or trim. Count the trailing 0's, strip all 0's, then add the trailing 0's back.

$num = 10100;
$trailing_cnt = strlen($num)-strlen(trim($num, "0"));
$num = str_replace('0','',$num).str_repeat('0', $trailing_cnt);

Upvotes: 0

air4x
air4x

Reputation: 5683

Try

echo preg_replace('/0+([1-9])/', '$1', $str);

Upvotes: 5

SomeKittens
SomeKittens

Reputation: 39532

You can use the regex [0]+(?=[1-9]) to find the zeros (using positive lookahead) and preg_replace to replace them with an empty string (assuming the number is already in string form).

$result = preg_replace("#[0]+(?=[1-9])#", "", "100010");

See it in action here

Upvotes: 2

Chris
Chris

Reputation: 5605

Not the prettiest but it works...

$str = "01110";

if(substr($str,-1) == 0){
    $str = str_replace("0","",$str)."0";
}else{
    $str = str_replace("0","",$str);
}

echo $str; // gives '1110'

Upvotes: -1

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