PHP Conference Japan 2024

String Functions

See Also

For even more powerful string handling and manipulating functions take a look at the Perl compatible regular expression functions. For working with multibyte character encodings, take a look at the Multibyte String functions.

Table of Contents

  • addcslashes — Quote string with slashes in a C style
  • addslashes — Quote string with slashes
  • bin2hex — Convert binary data into hexadecimal representation
  • chop — Alias of rtrim
  • chr — Generate a single-byte string from a number
  • chunk_split — Split a string into smaller chunks
  • convert_cyr_string — Convert from one Cyrillic character set to another
  • convert_uudecode — Decode a uuencoded string
  • convert_uuencode — Uuencode a string
  • count_chars — Return information about characters used in a string
  • crc32 — Calculates the crc32 polynomial of a string
  • crypt — One-way string hashing
  • echo — Output one or more strings
  • explode — Split a string by a string
  • fprintf — Write a formatted string to a stream
  • get_html_translation_table — Returns the translation table used by htmlspecialchars and htmlentities
  • hebrev — Convert logical Hebrew text to visual text
  • hebrevc — Convert logical Hebrew text to visual text with newline conversion
  • hex2bin — Decodes a hexadecimally encoded binary string
  • html_entity_decode — Convert HTML entities to their corresponding characters
  • htmlentities — Convert all applicable characters to HTML entities
  • htmlspecialchars — Convert special characters to HTML entities
  • htmlspecialchars_decode — Convert special HTML entities back to characters
  • implode — Join array elements with a string
  • join — Alias of implode
  • lcfirst — Make a string's first character lowercase
  • levenshtein — Calculate Levenshtein distance between two strings
  • localeconv — Get numeric formatting information
  • ltrim — Strip whitespace (or other characters) from the beginning of a string
  • md5 — Calculate the md5 hash of a string
  • md5_file — Calculates the md5 hash of a given file
  • metaphone — Calculate the metaphone key of a string
  • money_format — Formats a number as a currency string
  • nl_langinfo — Query language and locale information
  • nl2br — Inserts HTML line breaks before all newlines in a string
  • number_format — Format a number with grouped thousands
  • ord — Convert the first byte of a string to a value between 0 and 255
  • parse_str — Parses the string into variables
  • print — Output a string
  • printf — Output a formatted string
  • quoted_printable_decode — Convert a quoted-printable string to an 8 bit string
  • quoted_printable_encode — Convert a 8 bit string to a quoted-printable string
  • quotemeta — Quote meta characters
  • rtrim — Strip whitespace (or other characters) from the end of a string
  • setlocale — Set locale information
  • sha1 — Calculate the sha1 hash of a string
  • sha1_file — Calculate the sha1 hash of a file
  • similar_text — Calculate the similarity between two strings
  • soundex — Calculate the soundex key of a string
  • sprintf — Return a formatted string
  • sscanf — Parses input from a string according to a format
  • str_contains — Determine if a string contains a given substring
  • str_decrement — Decrement an alphanumeric string
  • str_ends_with — Checks if a string ends with a given substring
  • str_getcsv — Parse a CSV string into an array
  • str_increment — Increment an alphanumeric string
  • str_ireplace — Case-insensitive version of str_replace
  • str_pad — Pad a string to a certain length with another string
  • str_repeat — Repeat a string
  • str_replace — Replace all occurrences of the search string with the replacement string
  • str_rot13 — Perform the rot13 transform on a string
  • str_shuffle — Randomly shuffles a string
  • str_split — Convert a string to an array
  • str_starts_with — Checks if a string starts with a given substring
  • str_word_count — Return information about words used in a string
  • strcasecmp — Binary safe case-insensitive string comparison
  • strchr — Alias of strstr
  • strcmp — Binary safe string comparison
  • strcoll — Locale based string comparison
  • strcspn — Find length of initial segment not matching mask
  • strip_tags — Strip HTML and PHP tags from a string
  • stripcslashes — Un-quote string quoted with addcslashes
  • stripos — Find the position of the first occurrence of a case-insensitive substring in a string
  • stripslashes — Un-quotes a quoted string
  • stristr — Case-insensitive strstr
  • strlen — Get string length
  • strnatcasecmp — Case insensitive string comparisons using a "natural order" algorithm
  • strnatcmp — String comparisons using a "natural order" algorithm
  • strncasecmp — Binary safe case-insensitive string comparison of the first n characters
  • strncmp — Binary safe string comparison of the first n characters
  • strpbrk — Search a string for any of a set of characters
  • strpos — Find the position of the first occurrence of a substring in a string
  • strrchr — Find the last occurrence of a character in a string
  • strrev — Reverse a string
  • strripos — Find the position of the last occurrence of a case-insensitive substring in a string
  • strrpos — Find the position of the last occurrence of a substring in a string
  • strspn — Finds the length of the initial segment of a string consisting entirely of characters contained within a given mask
  • strstr — Find the first occurrence of a string
  • strtok — Tokenize string
  • strtolower — Make a string lowercase
  • strtoupper — Make a string uppercase
  • strtr — Translate characters or replace substrings
  • substr — Return part of a string
  • substr_compare — Binary safe comparison of two strings from an offset, up to length characters
  • substr_count — Count the number of substring occurrences
  • substr_replace — Replace text within a portion of a string
  • trim — Strip whitespace (or other characters) from the beginning and end of a string
  • ucfirst — Make a string's first character uppercase
  • ucwords — Uppercase the first character of each word in a string
  • utf8_decode — Converts a string from UTF-8 to ISO-8859-1, replacing invalid or unrepresentable characters
  • utf8_encode — Converts a string from ISO-8859-1 to UTF-8
  • vfprintf — Write a formatted string to a stream
  • vprintf — Output a formatted string
  • vsprintf — Return a formatted string
  • wordwrap — Wraps a string to a given number of characters
add a note

User Contributed Notes 2 notes

up
12
lrirwin at alum dot wustl dot edu
3 years ago
I'm converting 30 year old code and needed a string TAB function:

//tab function similar to TAB used in old BASIC languages
//though some of them did not truncate if the string were
//longer than the requested position
function tab($instring="",$topos=0){
if(strlen($instring)<$topos){
$result=str_pad($instring,$topos-1," ",STR_PAD_RIGHT);
}else{
$result=substr($instring,0,$topos-1);
}
return $result;
}

$pline="String with this tab to 50 and";
$tline=tab($pline,50)."finish it.";
echo $tline.PHP_EOL;
$pline="101010101020202020203030303030404040404050505050506060606060";
$tline=tab($pline,50)."finish it.";
echo $tline.PHP_EOL;

//Results in this output:
//String with this tab to 50 and finish it.
//1010101010202020202030303030304040404040505050505finish it.
up
-2
kristin at greenapple dot on dot ca
19 years ago
I really searched for a function that would do this as I've seen it in other languages but I couldn't find it here. This is particularily useful when combined with substr() to take the first part of a string up to a certain point.

strnpos() - Find the nth position of needle in haystack.

<?php

function strnpos($haystack, $needle, $occurance, $pos = 0) {

for (
$i = 1; $i <= $occurance; $i++) {
$pos = strpos($haystack, $needle, $pos) + 1;
}
return
$pos - 1;

}

?>

Example: Give me everything up to the fourth occurance of '/'.

<?php

$haystack
= "/home/username/www/index.php";
$needle = "/";

$root_dir = substr($haystack, 0, strnpos($haystack, $needle, 4));

echo
$root_dir;

?>

Returns: /home/username/www

Use this example with the server variable $_SERVER['SCRIPT_NAME'] as the haystack and you can self-discover a document's root directory for the purposes of locating global files automatically!
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