PHP provides built-in string functions for searching, modifying, comparing, formatting, and converting strings. These functions simplify common text-processing tasks in PHP applications.
- String Manipulation: Modify, trim, split, and combine strings.
- Searching and Comparison: Find substrings and compare text.
- Formatting and Conversion: Change letter case, format output, and encode or decode strings.
- Hashing and Security: Generate hashes and securely hash passwords using appropriate functions.
Common PHP String Functions
The PHP string functions are the inbuilt in PHP. The complete list of PHP string functions is given below:
| PHP String Functions | Description |
|---|---|
| addcslashes() | Adds backslashes before specified characters in a string, useful for escaping selected characters. |
| addslashes() | Adds backslashes before single quotes, double quotes, backslashes, and NULL bytes. |
| bin2hex() | Converts binary data into a hexadecimal string for readable representation. |
| chop() | Removes whitespace or specified characters from the end of a string; an alias of rtrim(). |
| chr() | Converts a numeric byte value into its corresponding character. |
| chunk_split() | Splits a string into smaller chunks and inserts a separator between them. |
| convert_uudecode() | Decodes a string that was encoded using uuencode. |
| convert_uuencode() | Encodes a string using uuencode, a format historically used to transfer binary data as text. |
| count_chars() | Counts character occurrences in a string or returns information about the characters it contains. |
| crc32() | Calculates a CRC32 checksum to help detect accidental changes in data. |
| crypt() | Generates a one-way hash of a string using a supported hashing method. |
| password_hash() | Creates a secure password hash for storing passwords safely. |
| echo | Displays one or more strings as output; it is a language construct, not a function. |
| explode() | Splits a string into an array wherever a specified delimiter occurs. |
| hex2bin() | Converts a hexadecimal string back into its binary representation. |
| implode() | Combines array elements into a single string using a specified separator. |
| join() | Combines array elements into a single string; an alias of implode(). |
| lcfirst() | Converts the first character of a string to lowercase. |
| levenshtein() | Calculates the minimum number of insertions, deletions, or substitutions needed to change one string into another. |
| ltrim() | Removes whitespace or specified characters from the beginning of a string. |
| md5_file() | Calculates the MD5 hash of a file, commonly for legacy checksum comparisons. |
| md5() | Calculates the MD5 hash of a string, often used for legacy checksums but not secure password storage. |
| metaphone() | Generates a phonetic representation of a string to help compare words that sound similar. |
| nl2br() | Inserts HTML line-break tags before newline characters so line breaks appear in HTML output. |
| number_format() | Formats a number with grouped thousands and a specified number of decimal places. |
| ord() | Returns the numeric byte value of the first byte in a string. |
| parse_str() | Parses a URL query string into variables or an associative array. |
| quoted_printable_decode() | Decodes a quoted-printable encoded string into its original representation. |
| quoted_printable_encode() | Encodes a string using quoted-printable encoding, commonly used in email messages. |
| quotemeta() | Escapes special characters used in regular expressions by adding backslashes. |
| rtrim() | Removes whitespace or specified characters from the end of a string. |
| sha1_file() | Calculates the SHA-1 hash of a file, commonly for legacy checksum comparisons. |
| sha1() | Calculates the SHA-1 hash of a string, but should not be used for password storage. |
| similar_text() | Calculates how similar two strings are and can return a similarity percentage. |
| soundex() | Generates a phonetic key to help identify words with similar pronunciations. |
| str_pad() | Adds characters to the beginning, end, or both sides of a string until it reaches a specified length. |
| str_repeat() | Repeats a string a specified number of times. |
| str_replace() | Replaces every occurrence of a search value with a replacement value in a string. |
| str_rot13() | Replaces each alphabetic character with the character 13 positions away in the alphabet. |
| str_shuffle() | Randomly rearranges the characters in a string. |
| str_split() | Splits a string into an array of byte sequences of a specified length. |
| str_word_count() | Counts the words in a string or returns an array containing its words. |
| strcasecmp() | Compares two strings without distinguishing between uppercase and lowercase letters. |
| strchr() | Finds the first occurrence of a substring and returns the matching portion of the string; an alias of strstr(). |
| strcmp() | Compares two strings case-sensitively and returns a value indicating their sort order. |
| strcoll() | Compares two strings according to the current locale's collation rules. |
| strcspn() | Returns the length of the initial part of a string before any specified character appears. |
| strip_tags() | Removes HTML and PHP tags from a string, optionally preserving specified tags. |
| stripos() | Finds the position of the first occurrence of a substring without distinguishing between letter case. |
| stripslashes() | Removes backslashes used to escape characters in a string. |
| stristr() | Finds the first occurrence of a substring without distinguishing between letter case and returns the matching portion. |
| strlen() | Returns the length of a string in bytes. |
| strnatcasecmp() | Compares two strings using natural ordering without distinguishing between letter case, so numeric parts are compared naturally. |
| strnatcmp() | Compares two strings using natural ordering, so numeric parts are compared naturally. |
| strncasecmp() | Compares the first specified number of characters in two strings without distinguishing between letter case. |
| strncmp() | Compares the first specified number of characters in two strings, distinguishing between letter case. |
| strpbrk() | Finds the first occurrence of any character from a specified set and returns the remaining string. |
| strpos() | Finds the position of the first occurrence of a substring, distinguishing between letter case. |
| strrchr() | Finds the last occurrence of a specified character and returns the remaining string from that position. |
| strrev() | Reverses the order of characters in a string. |
| strripos() | Finds the position of the last occurrence of a substring without distinguishing between letter case. |
| strrpos() | Finds the position of the last occurrence of a substring, distinguishing between letter case. |
| strspn() | Returns the length of the initial part of a string containing only characters from a specified set. |
| strstr() | Finds the first occurrence of a substring and returns the matching portion of the string. |
| strtok() | Splits a string into tokens using specified delimiter characters, one token at a time. |
| strtolower() | Converts all alphabetic characters in a string to lowercase. |
| strtoupper() | Converts all alphabetic characters in a string to uppercase. |
| strtr() | Replaces specified characters or substrings with other characters or substrings. |
| substr_compare() | Compares part of one string with another string, optionally using a specified length and comparison mode. |
| substr_count() | Counts how many times a substring occurs within a string. |
| substr_replace() | Replaces a specified portion of a string with another string. |
| substr() | Extracts and returns a portion of a string from a specified position. |
| trim() | Removes whitespace or specified characters from both the beginning and end 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. |
| vprintf() | Displays a formatted string using values supplied in an array. |
| vsprintf() | Returns a formatted string using values supplied in an array. |
| wordwrap() | Wraps a string into lines of a specified width using a chosen break string. |
Benefits
- Built-in Support: Use many string functions without installing additional libraries.
- Simplified Processing: Perform common text operations with ready-made functions.
- Improved Readability: Replace repetitive string-processing logic with function calls.
- Versatile Operations: Handle searching, formatting, comparison, conversion, and encoding.
Note: addslashes() is not a substitute for prepared SQL statements, and password_hash() should be used instead of md5() or sha1() for password storage.