PHP - Strings


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PHP Strings

Strings are one of the most common data types in PHP. It is used for storing text. It can be created by enclosing characters either in single quotation marks or double quotation marks. It can be assigned to a variable using = sign.

$MyString = "Hello World!.";
$MyString = 'Hello World!.';

Access character of a String

A character (also called element) of a string can be accessed with it's index number. In PHP, index number starts with 0 in forward direction and -1 in backward direction. The below figure and example describe the indexing concept of a string.

String Indexing:

PHP String Indexing

<?php
  $MyString = "HELLO";
  echo $MyString[1]."\n"; 
  echo $MyString[-1]."\n"; 
?> 

Output

E
O   

String Length

The strlen() function can be used in PHP to find out total number of characters in the given string.

<?php
  $MyString = "Hello World";
  echo strlen($MyString)."\n"; 
?>

Output

11

Word count of a string

The str_word_count() function is used to find out total number of words in the given string.

<?php
  $MyString = "Hello World";
  echo str_word_count($MyString)."\n"; 
?>

Output

2

Reverse a string

A string in PHP can be reversed using strrev() function. Please note that it does not change the original string, only returns the reverse of the original string.

<?php
  $MyString = "Hello World";
  echo strrev($MyString)."\n"; 
?>

Output

dlroW olleH

Check a text in the String

The PHP strpos() function is used to search the specified text in a given string. It returns the position of the text in the string. If no match is found, it returns 'FALSE'

<?php
  $MyString = "Hello World";
  echo strpos($MyString, 'World')."\n";
?>

Output

6

Replace a text in the String

The PHP str_replace() function is used to replace the specified text with another text in a given string. In the below example 'World' is replaced by 'PHP'.

<?php
  $MyString = "Hello World";
  echo str_replace('World', 'PHP', $MyString)."\n";
?>

Output

Hello PHP
PHP String Functions
FunctionDescription
addcslashes() Returns a string with backslashes in front of the specified characters
addslashes() Returns a string with backslashes in front of predefined characters
bin2hex() Converts a string of ASCII characters to hexadecimal values
chop() Removes whitespace or other characters from the right end of a string
chr() Returns a character from a specified ASCII value
chunk_split() Splits a string into a series of smaller parts
convert_cyr_string() Converts a string from one Cyrillic character-set to another
convert_uudecode() Decodes a uuencoded string
convert_uuencode() Encodes a string using the uuencode algorithm
count_chars() Returns information about characters used in a string
crc32() Calculates a 32-bit CRC for a string
crypt() One-way string hashing
echo() Outputs one or more strings
explode() Breaks a string into an array
fprintf() Writes a formatted string to a specified output stream
get_html_translation_table() Returns the translation table used by htmlspecialchars() and htmlentities()
hebrev() Converts Hebrew text to visual text
hebrevc() Converts Hebrew text to visual text and new lines (\n) into
hex2bin() Converts a string of hexadecimal values to ASCII characters
html_entity_decode() Converts HTML entities to characters
htmlentities() Converts characters to HTML entities
htmlspecialchars_decode() Converts some predefined HTML entities to characters
htmlspecialchars() Converts some predefined characters to HTML entities
implode() Returns a string from the elements of an array
join() Alias of implode()
lcfirst() Converts the first character of a string to lowercase
levenshtein() Returns the Levenshtein distance between two strings
localeconv() Returns locale numeric and monetary formatting information
ltrim() Removes whitespace or other characters from the left side of a string
md5() Calculates the MD5 hash of a string
md5_file() Calculates the MD5 hash of a file
metaphone() Calculates the metaphone key of a string
money_format() Returns a string formatted as a currency string
nl_langinfo() Returns specific local information
nl2br() Inserts HTML line breaks in front of each newline in a string
number_format() Formats a number with grouped thousands
ord() Returns the ASCII value of the first character of a string
parse_str() Parses a query string into variables
print() Outputs one or more strings
printf() Outputs a formatted string
quoted_printable_decode() Converts a quoted-printable string to an 8-bit string
quoted_printable_encode() Converts an 8-bit string to a quoted printable string
quotemeta() Quotes meta characters
rtrim() Removes whitespace or other characters from the right side of a string
setlocale() Sets locale information
sha1() Calculates the SHA-1 hash of a string
sha1_file() Calculates the SHA-1 hash of a file
similar_text() Calculates the similarity between two strings
soundex() Calculates the soundex key of a string
sprintf() Writes a formatted string to a variable
sscanf() Parses input from a string according to a format
str_getcsv() Parses a CSV string into an array
str_ireplace() Replaces some characters in a string (case-insensitive)
str_pad() Pads a string to a new length
str_repeat() Repeats a string a specified number of times
str_replace() Replaces some characters in a string (case-sensitive)
str_rot13() Performs the ROT13 encoding on a string
str_shuffle() Randomly shuffles all characters in a string
str_split() Splits a string into an array
str_word_count() Count the number of words in a string
strcasecmp() Compares two strings (case-insensitive)
strchr() Finds the first occurrence of a string inside another string (alias of strstr())
strcmp() Compares two strings (case-sensitive)
strcoll() Compares two strings (locale based string comparison)
strcspn() Returns the number of characters found in a string before any part of some specified characters are found
strip_tags() Strips HTML and PHP tags from a string
stripcslashes() Unquotes a string quoted with addcslashes()
stripslashes() Unquotes a string quoted with addslashes()
stripos() Returns the position of the first occurrence of a string inside another string (case-insensitive)
stristr() Finds the first occurrence of a string inside another string (case-insensitive)
strlen() Returns the length of a string
strnatcasecmp() Compares two strings using a "natural order" algorithm (case-insensitive)
strnatcmp() Compares two strings using a "natural order" algorithm (case-sensitive)
strncasecmp() String comparison of the first n characters (case-insensitive)
strncmp() String comparison of the first n characters (case-sensitive)
strpbrk() Searches a string for any of a set of characters
strpos() Returns the position of the first occurrence of a string inside another string (case-sensitive)
strrchr() Finds the last occurrence of a string inside another string
strrev() Reverses a string
strripos() Finds the position of the last occurrence of a string inside another string (case-insensitive)
strrpos() Finds the position of the last occurrence of a string inside another string (case-sensitive)
strspn() Returns the number of characters found in a string that contains only characters from a specified charlist
strstr() Finds the first occurrence of a string inside another string (case-sensitive)
strtok() Splits a string into smaller strings
strtolower() Converts a string to lowercase letters
strtoupper() Converts a string to uppercase letters
strtr() Translates certain characters in a string
substr() Returns a part of a string
substr_compare() Compares two strings from a specified start position (binary safe and optionally case-sensitive)
substr_count() Counts the number of times a substring occurs in a string
substr_replace() Replaces a part of a string with another string
trim() Removes whitespace or other characters from both sides of a string
ucfirst() Converts the first character of a string to uppercase
ucwords() Converts the first character of each word in a string to uppercase
vfprintf() Writes a formatted string to a specified output stream
vprintf() Outputs a formatted string
vsprintf() Writes a formatted string to a variable
wordwrap() Wraps a string to a given number of characters

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