substr_count

(PHP 4, PHP 5, PHP 7, PHP 8)

substr_count — Bir dizge içinde belli bir alt dizgeden kaç tane bulunduğunu bulur

Açıklama

substr_count(
    string $samanlık,
    string $iğne,
    int $başlangıç = 0,
    ?int $uzunluk = null
): int

substr_count() işlevi samanlık dizgesi içindeki iğne alt dizgelerinin sayısını döndürür. iğne bağımsız değişkeni harf büyüklüğüne duyarlıdır.

Bilginize:
Bu işlev, birbirinin üstüne binmiş alt dizgeleri saymaz. Örnek için aşağıya bakın!

Bağımsız Değişkenler

samanlık: Araştırılacak dizge.
iğne: Aranacak dizge.
başlangıç: Saymaya başlanacak konum. Negatifse saymaya dizgenin sonundan başlanır.
uzunluk: Dizgenin ne kadarlık parçasında arama yapılacağı burada belirtilir. Eğer başlangıç artı uzunluk, samanlık uzunluğundan büyük ise bir uyarı oluşur. uzunluk negatifse samanlık dizgesinin sonundan başlar.

Dönen Değerler

İşlev bir tamsayı döndürür.

Sürüm Bilgisi

Sürüm:	Açıklama
8.0.0	`uzunluk` artık `null` olabiliyor.
7.1.0	Negatif `başlangıç` ve `uzunluk` desteği eklendi. `uzunluk` ayrıca, artık `0` olabiliyor.

Örnekler

Örnek 1 - substr_count() örneği

<?php
$text = 'This is a test';
echo strlen($text); // 14

echo substr_count($text, 'is'); // 2

// Arama 's is a test' parçasında yapılır ve 1 basılır
echo substr_count($text, 'is', 3);

// Arama 's i' parçasında yapılır ve 0 basılır
echo substr_count($text, 'is', 3, 3);

// 5+10 > 14 olduğundan bir uyarı verilir
echo substr_count($text, 'is', 5, 10);


// üst üste binen alt dizgeleri saymadığından sadece 1 basılır
$text2 = 'gcdgcdgcd';
echo substr_count($text2, 'gcdgcd');
?>

Ayrıca Bakınız

count_chars() - Bir dizgedeki karakterler hakkında bilgi döndürür
strpos() - Bir alt dizgenin ilkinin konumunu bulur
substr() - Dizgenin bir kısmını döndürür
strstr() - İlk alt dizgeyi bulur

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User Contributed Notes 7 notes

down

tuxedobob ¶

8 years ago

It's worth noting this function is surprisingly fast. I first ran it against a ~500KB string on our web server. It found 6 occurrences of the needle I was looking for in 0.0000 seconds. Yes, it ran faster than microtime() could measure.

Looking to give it a challenge, I then ran it on a Mac laptop from 2010 against a 120.5MB string. For one test needle, it found 2385 occurrences in 0.0266 seconds. Another test needs found 290 occurrences in 0.114 seconds.

Long story short, if you're wondering whether this function is slowing down your script, the answer is probably not.

down

flobi at flobi dot com ¶

18 years ago

Making this case insensitive is easy for anyone who needs this.  Simply convert the haystack and the needle to the same case (upper or lower).

substr_count(strtoupper($haystack), strtoupper($needle))

down

tweston at bangordailynews dot com ¶

9 years ago

To account for the case that jrhodes has pointed out, we can change the line to:

substr_count ( implode( ',', $haystackArray ), $needle );

This way:

array (
  0 => "mystringth",
  1 => "atislong"
);

Becomes

mystringth,atislong

Which brings the count for $needle = "that" to 0 again.

down

-1

jrhodes at roket-enterprises dot com ¶

15 years ago

It was suggested to use

substr_count ( implode( $haystackArray ), $needle );

instead of the function described previously, however this has one flaw.  For example this array:

array (
  0 => "mystringth",
  1 => "atislong"
);

If you are counting "that", the implode version will return 1, but the function previously described will return 0.

down

-1

info at fat-fish dot co dot il ¶

17 years ago

a simple version for an array needle (multiply sub-strings):
<?php

function substr_count_array( $haystack, $needle ) {
     $count = 0;
     foreach ($needle as $substring) {
          $count += substr_count( $haystack, $substring);
     }
     return $count;
}
?>

down

-1

XinfoX X at X XkarlX X-X XphilippX X dot X XdeX ¶

21 years ago

Yet another reference to the "cgcgcgcgcgcgc" example posted by "chris at pecoraro dot net":

Your request can be fulfilled with the Perl compatible regular expressions and their lookahead and lookbehind features.

The example

 $number_of_full_pattern = preg_match_all('/(cgc)/', "cgcgcgcgcgcgcg", $chunks);

works like the substr_count function. The variable $number_of_full_pattern has the value 3, because the default behavior of Perl compatible regular expressions is to consume the characters of the string subject that were matched by the (sub)pattern. That is, the pointer will be moved to the end of the matched substring.
But we can use the lookahead feature that disables the moving of the pointer:

 $number_of_full_pattern = preg_match_all('/(cg(?=c))/', "cgcgcgcgcgcgcg", $chunks);

In this case the variable $number_of_full_pattern has the value 6.
Firstly a string "cg" will be matched and the pointer will be moved to the end of this string. Then the regular expression looks ahead whether a 'c' can be matched. Despite of the occurence of the character 'c' the pointer is not moved.

down

-5

php at blink dot at ¶

10 years ago

This will handle a string where it is unknown if comma or period are used as thousand or decimal separator. Only exception where this leads to a conflict is when there is only a single comma or period and 3 possible decimals (123.456 or 123,456). An optional parameter is passed to handle this case (assume thousands, assume decimal, decimal when period, decimal when comma). It assumes an input string in any of the formats listed below.

function toFloat($pString, $seperatorOnConflict="f")
{
    $decSeperator=".";
    $thSeperator="";

    $pString=str_replace(" ", $thSeperator, $pString);

    $firstPeriod=strpos($pString, ".");
    $firstComma=strpos($pString, ",");
    if($firstPeriod!==FALSE && $firstComma!==FALSE) {
        if($firstPeriod<$firstComma) {
            $pString=str_replace(".", $thSeperator, $pString);
            $pString=str_replace(",", $decSeperator, $pString);
        }
        else {
            $pString=str_replace(",", $thSeperator, $pString);
        }
    }
    else if($firstPeriod!==FALSE || $firstComma!==FALSE) {
        $seperator=$firstPeriod!==FALSE?".":",";
        if(substr_count($pString, $seperator)==1) {
            $lastPeriodOrComma=strpos($pString, $seperator);
            if($lastPeriodOrComma==(strlen($pString)-4) && ($seperatorOnConflict!=$seperator && $seperatorOnConflict!="f")) {
                $pString=str_replace($seperator, $thSeperator, $pString);
            }
            else {
                $pString=str_replace($seperator, $decSeperator, $pString);
            }
        }
        else {
            $pString=str_replace($seperator, $thSeperator, $pString);
        }
    }
    return(float)$pString;
}

function testFloatParsing() { 
    $floatvals = array( 
        "22 000", 
        "22,000", 
        "22.000", 
        "123 456",
        "123,456",
        "123.456",
        "22 000,76", 
        "22.000,76", 
        "22,000.76", 
        "22000.76", 
        "22000,76", 
        "1.022.000,76", 
        "1,022,000.76", 
        "1,000,000", 
        "1.000.000", 
        "1022000.76", 
        "1022000,76", 
        "1022000", 
        "0.76", 
        "0,76", 
        "0.00", 
        "0,00", 
        "1.00", 
        "1,00", 
        "-22 000,76", 
        "-22.000,76", 
        "-22,000.76", 
        "-22 000", 
        "-22,000", 
        "-22.000", 
        "-22000.76", 
        "-22000,76", 
        "-1.022.000,76", 
        "-1,022,000.76", 
        "-1,000,000", 
        "-1.000.000", 
        "-1022000.76", 
        "-1022000,76", 
        "-1022000", 
        "-0.76", 
        "-0,76", 
        "-0.00", 
        "-0,00", 
        "-1.00", 
        "-1,00" 
    ); 
    
    echo "<table> 
        <tr> 
            <th>String</th> 
            <th>thousands</th> 
            <th>fraction</th> 
            <th>dec. if period</th> 
            <th>dec. if comma</th> 
        </tr>"; 
        
    foreach ($floatvals as $fval) { 
        echo "<tr>"; 
        echo "<td>" . (string) $fval . "</td>"; 
        
        echo "<td>" . (float) toFloat($fval, "") . "</td>"; 
        echo "<td>" . (float) toFloat($fval, "f") . "</td>"; 
        echo "<td>" . (float) toFloat($fval, ".") . "</td>"; 
        echo "<td>" . (float) toFloat($fval, ",") . "</td>"; 
        echo "</tr>"; 
    } 
    echo "</table>"; 
}

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