My PHP Performance Benchmarks

PHP version 7.4.2 is running on this server.

Please note that these are micro benchmarks. Micro benchmarks are stupid. I created this comparison to learn something about PHP and how the PHP compiler works. This can not be used to compare PHP versions or servers.

Check if a String is empty

Method Undefined Null False Empty string String "0" String "1" Long string Summary Index
if ( ! $var )4 ms>0 ms>0 ms>0 ms>0 ms>0 ms>0 ms4 ms1117
if (empty( $var) )>0 ms>0 ms>0 ms>0 ms>0 ms>0 ms>0 ms>0 ms100
if ( $var == "" )>0 ms>0 ms>0 ms>0 ms>0 ms>0 ms9 ms10 ms2877
if ( "" == $var )>0 ms>0 ms>0 ms>0 ms>0 ms>0 ms9 ms10 ms2763
if ( $var === "" )>0 ms>0 ms>0 ms>0 ms>0 ms>0 ms>0 ms>0 ms103
if ( "" === $var )>0 ms>0 ms>0 ms>0 ms>0 ms>0 ms>0 ms>0 ms102
if ( strcmp( $var, "" ) == 0 )>0 ms>0 ms>0 ms>0 ms>0 ms>0 ms>0 ms1 ms258
if ( strcmp( "", $var ) == 0 )>0 ms>0 ms>0 ms>0 ms>0 ms>0 ms>0 ms1 ms256
if ( strlen( $var ) == 0 )>0 ms>0 ms>0 ms>0 ms>0 ms>0 ms>0 ms1 ms162
if ( ! strlen( $var ) )>0 ms>0 ms>0 ms>0 ms>0 ms>0 ms>0 ms>0 ms125

My conclusion: In most cases, use empty() because it does not trigger a warning when used with undefined variables. Note that empty( "0" ) returns true. Use strlen() if you want to detect "0". Try to avoid == at all because it may cause strange behaviour (e.g. "9a" == 9 returns true). Prefer === over == and !== over != if possible because it does compare the variable types in addition to the contents.

Compare two Strings

Method Equal First character not equal Last character not equal Summary Index
$a == $b>0 ms>0 ms>0 ms>0 ms100
!strcmp( $a, $b )>0 ms>0 ms>0 ms1 ms215
strcmp( $a, $b ) == 0>0 ms>0 ms>0 ms1 ms222
strcmp( $a, $b ) === 0>0 ms>0 ms>0 ms1 ms201
strcasecmp( $a, $b ) === 0>0 ms>0 ms1 ms2 ms358

My conclusion: Use what fits your needs.

Check if a String contains another String

Method Not found Found at the start Found in the middle Found at the end Summary Index
strstr( $haystack, $needle )>0 ms>0 ms>0 ms>0 ms1 ms33900
strpos( $haystack, $needle ) !== FALSE>0 ms>0 ms>0 ms>0 ms1 ms27075
strstr( $haystack, $needle ) !== FALSE>0 ms>0 ms>0 ms>0 ms1 ms35300
stristr( $haystack, $needle )1 ms1 ms1 ms1 ms2 ms127875
preg_match( "/$needle/", $haystack )>0 ms>0 ms>0 ms>0 ms1 ms58975
preg_match( "/$needle/i", $haystack )>0 ms>0 ms>0 ms>0 ms1 ms61138
preg_match( "/$needle/S", $haystack )>0 ms>0 ms>0 ms>0 ms1 ms60588
Function ereg is deprecated since 5.3>0 ms0 ms>0 ms0 ms>0 ms100

My conclusion: It does not matter if you use strstr() or strpos(). Use the preg…() functions only if you need the power of regular expressions. Never use the ereg…() functions.

Check if a String starts with another String

Method Not found Found at the start Found in the middle Found at the end Summary Index
strncmp( $haystack, $needle, strlen( $needle ) ) === 0>0 ms>0 ms>0 ms>0 ms>0 ms119
strncmp( $haystack, $needle, 4 ) === 0>0 ms>0 ms>0 ms>0 ms>0 ms100
strncasecmp( $haystack, $needle, strlen( $needle ) ) === 0>0 ms>0 ms>0 ms>0 ms>0 ms106
strpos( $haystack, $needle ) === 0>0 ms>0 ms>0 ms>0 ms>0 ms121
substr( $haystack, 0, strlen( $needle ) ) === $needle>0 ms>0 ms>0 ms>0 ms>0 ms141
strcmp( substr( $haystack, 0, strlen( $needle ) ), $needle ) === 0>0 ms>0 ms>0 ms>0 ms1 ms215
preg_match( "/^" . preg_quote( $needle, "/" ) . "/", $haystack )>0 ms>0 ms>0 ms>0 ms2 ms539

My conclusion: strpos() is very fast and can be used in almost all cases. strncmp() is good if you are looking for a constant length needle.

Check if a String ends with another String

Method Not found Found at the start Found in the middle Found at the end Summary Index
substr( $haystack, strlen( $haystack ) - strlen( $needle) ) === $needle>0 ms>0 ms>0 ms>0 ms1 ms105
substr( $haystack, -strlen( $needle) ) === $needle>0 ms>0 ms>0 ms>0 ms1 ms100
strcmp( substr( $haystack, - strlen( $needle) ), $needle) === 0>0 ms>0 ms>0 ms>0 ms1 ms143
preg_match( "/" . preg_quote( $needle, "/" ) . "$/", $haystack )1 ms1 ms1 ms1 ms2 ms390

My conclusion: Using substr() with a negative position is a good trick.

Replace a String inside another String

Method Not found Found at the start Found in the middle Found at the end Summary Index
str_replace( $search, $replace, $subject )>0 ms>0 ms>0 ms>0 ms1 ms30925
preg_replace( "/$search/", $replace, $subject )>0 ms1 ms1 ms>0 ms2 ms61292
preg_replace( "/$search/S", $replace, $subject )>0 ms1 ms1 ms>0 ms2 ms61067
Function ereg_replace is deprecated since 5.3>0 ms0 ms>0 ms0 ms>0 ms100

My conclusion: Never use the ereg…() functions.

Trim Characters from the Beginning and End of a String

Method Not found Found at start Found at end Found at both sides Summary Index
trim( $string, "," )>0 ms>0 ms>0 ms>0 ms>0 ms100
preg_replace( '/^,*|,*$/', "", $string )1 ms1 ms1 ms1 ms3 ms5602
preg_replace( '/^,*|,*$/m', "", $string )3 ms3 ms4 ms4 ms14 ms31230
preg_replace( '/^,+|,+$/', "", $string )>0 ms>0 ms>0 ms>0 ms>0 ms446
preg_replace( '/^,+|,+$/m', "", $string )>0 ms>0 ms>0 ms>0 ms>0 ms390
preg_replace( '/^,+/', "", preg_replace( '/,+$/', "", … ) )>0 ms>0 ms>0 ms>0 ms>0 ms738

My conclusion: Always benchmark your regular expressions! In this case, with .* you also replace nothing with nothing which takes time because there is a lot of “nothing” in every string.

Split a String into an Array

Method Empty string Single occurrence Multiple occurrences Summary Index
explode( ",", $string )>0 ms>0 ms2 ms2 ms52125
Function split is deprecated since 5.3>0 ms>0 ms>0 ms>0 ms100
preg_split( "/,/", $string )>0 ms>0 ms3 ms3 ms84688
preg_match_all( '/[^,]+/', $string, $matches )>0 ms1 ms4 ms6 ms145844

My conclusion: Don't use split(). It's deprecated in PHP 5.3 and will be removed in PHP 6.

Loop a numerical indexed Array of Strings

Method Summary Index
for ( $i = 0; $i < count( $array ; $i++ )>0 ms392
for ( $i = 0, $count = count( $array ); $i < $count; $i++ )>0 ms100
for ( $i = count( $array ) - 1; $i >= 0; $i-- )>0 ms113
for ( $i = count( $array ) - 1; $i >= 0; --$i )>0 ms131
$i = count( $array ); while ( $i-- )>0 ms209

My conclusion: count() is horribly slow. Always precalculate it, if possible.

Get Elements from an Array

Method Summary Index
$array[0]4 ms104
$array['key']3 ms100

My conclusion: I like associative arrays.

Implode an Array

Method Summary Index
implode( " ", $array )>0 ms103
"$array[0] $array[1] $array[2]">0 ms100
$array[0] . " " . $array[1] . " " . $array[2]>0 ms100
sprintf( "%s %s %s", $array[0], $array[1], $array[2] )1 ms1740
vsprintf( "%s %s %s", $array )1 ms2116

My conclusion: String concatenation is a cheap operation in PHP. Don't waste your time benchmarking this.

The single vs. double Quotes Myth

Method Summary Index
'contains no dollar signs'>0 ms103
"contains no dollar signs">0 ms103
'$variables $are $not $replaced'>0 ms103
"\$variables \$are \$not \$replaced">0 ms100
"$variables $are $replaced">0 ms103
$variables . ' ' . $are . ' ' . $replaced>0 ms100
$variables . " " . $are . " " . $replaced>0 ms106

My conclusion: It does not matter if you use single or double quotes at all. The inclusion of variables has a measurable effect, but that's independent from the quotes.