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name

A PHP Error was encountered

Severity: Notice

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Filename: views/question.php

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Backtrace:

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Line: 190
Function: _error_handler

File: /var/www/stackquestions.com/public_html/application/controllers/Questions.php
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Function: view

File: /var/www/stackquestions.com/public_html/index.php
Line: 315
Function: require_once

name Punditsdkoslkdosdkoskdo

startsWith() and endsWith() functions in PHP

How can I write two functions that would take a string and return if it starts with the specified character/string or ends with it?

For example:

$str = '|apples}';

echo startsWith($str, '|'); //Returns true
echo endsWith($str, '}'); //Returns true

Fastest endsWith() solution:

# Checks if a string ends in a string
function endsWith($haystack, $needle) {
    return substr($haystack,-strlen($needle))===$needle;
}

Benchmark:

# This answer
function endsWith($haystack, $needle) {
    return substr($haystack,-strlen($needle))===$needle;
}

# Accepted answer
function endsWith2($haystack, $needle) {
    $length = strlen($needle);

    return $length === 0 ||
    (substr($haystack, -$length) === $needle);
}

# Second most-voted answer
function endsWith3($haystack, $needle) {
    // search forward starting from end minus needle length characters
    if ($needle === '') {
        return true;
    }
    $diff = strlen($haystack) - strlen($needle);
    return $diff >= 0 && strpos($haystack, $needle, $diff) !== false;
}

# Regex answer
function endsWith4($haystack, $needle) {
    return preg_match('/' . preg_quote($needle, '/') . '$/', $haystack);
}

function timedebug() {
    $test = 10000000;

    $time1 = microtime(true);
    for ($i=0; $i < $test; $i++) {
        $tmp = endsWith('TestShortcode', 'Shortcode');
    }
    $time2 = microtime(true);
    $result1 = $time2 - $time1;

    for ($i=0; $i < $test; $i++) {
        $tmp = endsWith2('TestShortcode', 'Shortcode');
    }
    $time3 = microtime(true);
    $result2 = $time3 - $time2;

    for ($i=0; $i < $test; $i++) {
        $tmp = endsWith3('TestShortcode', 'Shortcode');
    }
    $time4 = microtime(true);
    $result3 = $time4 - $time3;

    for ($i=0; $i < $test; $i++) {
        $tmp = endsWith4('TestShortcode', 'Shortcode');
    }
    $time5 = microtime(true);
    $result4 = $time5 - $time4;

    echo $test.'x endsWith: '.$result1.' seconds # This answer
'; echo $test.'x endsWith2: '.$result4.' seconds # Accepted answer
'; echo $test.'x endsWith3: '.$result2.' seconds # Second most voted answer
'; echo $test.'x endsWith4: '.$result3.' seconds # Regex answer
'; exit; } timedebug();

Benchmark Results:

10000000x endsWith: 1.5760900974274 seconds # This answer
10000000x endsWith2: 3.7102129459381 seconds # Accepted answer
10000000x endsWith3: 1.8731069564819 seconds # Second most voted answer
10000000x endsWith4: 2.1521229743958 seconds # Regex answer
  • 0
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This question already has many answers, but in some cases you can settle for something simpler than all of them. If the string you're looking for is known (hardcoded), you can use regular expressions without any quoting etc.

Check if a string starts with 'ABC':

preg_match('/^ABC/', $myString); // "^" here means beginning of string

ends with 'ABC':

preg_match('/ABC$/', $myString); // "$" here means end of string

In my simple case, I wanted to check if a string ends with slash:

preg_match('#/$#', $myPath);   // Use "#" as delimiter instead of escaping slash

The advantage: since it's very short and simple, you don't have to define a function (such as endsWith()) as shown above.

But again -- this is not a solution for every case, just this very specific one.

  • 1
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Here's a multi-byte safe version of the accepted answer, it works fine for UTF-8 strings:

function startsWith($haystack, $needle)
{
    $length = mb_strlen($needle, 'UTF-8');
    return (mb_substr($haystack, 0, $length, 'UTF-8') === $needle);
}

function endsWith($haystack, $needle)
{
    $length = mb_strlen($needle, 'UTF-8');
    return $length === 0 ||
        (mb_substr($haystack, -$length, $length, 'UTF-8') === $needle);
}
  • 1
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You can use substr_compare function to check start-with and ends-with:

function startsWith($haystack, $needle) {
    return substr_compare($haystack, $needle, 0, strlen($needle)) === 0;
}
function endsWith($haystack, $needle) {
    return substr_compare($haystack, $needle, -strlen($needle)) === 0;
}

This should be one of the fastest solutions on PHP 7 (benchmark script). Tested against 8KB haystacks, various length needles and full, partial and no match cases. strncmp is a touch faster for starts-with but it cannot check ends-with.

  • 0
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function startsWith($haystack, $needle)
{
     $length = strlen($needle);
     return (substr($haystack, 0, $length) === $needle);
}

function endsWith($haystack, $needle)
{
    $length = strlen($needle);
    if ($length == 0) {
        return true;
    }

    return (substr($haystack, -$length) === $needle);
}

Use this if you don't want to use a regex.

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