Summary of PHP string processing functions

The following are the string processing functions that come with PHP itself.
addcslashes — Add backslash escape characters to some characters in a string
addslashes — Escape characters in a string in a specified way
bin2hex — Convert binary data to hexadecimal representation
chop — alias function for rtrim()
chr — Returns the ASCII code of a character
chunk_split — Split a string into small chunks according to a certain character length
convert_cyr_string — Convert Cyrillic characters to other characters
convert_uudecode — Decrypt a string
convert_uuencode — Encrypt a string
count_chars — Returns character usage information in a string
crc32 — Compute the crc32 polynomial of a string
crypt — one-way hash encryption function
echo — used to display some content
explode — Convert a string into an array using delimiters
fprintf — Return data as required and write directly to the document stream
get_html_translation_table — Returns HTML entities that can be translated
hebrev — Convert Hebrew-encoded strings to visual text
hebrevc — Convert Hebrew-encoded strings to visual text
html_entity_decode — The inverse function of htmlentities () function, converts HTML entities into characters
htmlentities — Convert some characters in a string to HTML entities
htmlspecialchars_decode — The inverse function of htmlspecialchars() function, converts HTML entities into characters
htmlspecialchars — Convert some characters in a string to HTML entities
implode — Convert an array into a string using a specific delimiter
join — Convert array to string, alias of implode() function
levenshtein — Calculate the difference between two words
localeconv — Get number-related format definitions
ltrim — removes whitespace or specified characters on the left side of a string
md5_file — Encrypt a file with MD5 algorithm
md5 — Encrypt a string with MD5 algorithm
metaphone — determine the pronunciation rules of a string
money_format — Output of numbers formatted according to arguments
nl_langinfo — Query language and local information
nl2br — Replace newline character "/n" in a string with "
"
number_format — Output of numbers formatted according to parameters
ord — Convert an ASCII code to a character
parse_str — Convert strings in a certain format into variables and values ​​
print — used to print a single value
printf — display data as required
quoted_printable_decode — Encrypt a string into an 8-bit binary string
quotemeta — escape several specific characters
rtrim — Remove whitespace or specified characters on the right side of a string
setlocale — Set local formats for numbers, dates, etc.
sha1_file — Encrypt a file with SHA1 algorithm
sha1 — Encrypt a string with SHA1 algorithm
similar_text — Compares two strings and returns the number of similar characters that the system considers
soundex — Determine the pronunciation rules of a string
sprintf — returns data as required, but does not output
sscanf — can format strings
str_ireplace — Matches and replaces strings like str_replace() function, but case-insensitive
str_pad — padding on both sides of a string
str_repeat — Repeat string combinations
str_replace — Match and replace strings
str_rot13 — ROT13 encrypts a string
str_shuffle — Randomly sort the characters in a string
str_split — Split a string into an array according to character spacing
str_word_count — Get the English word information in the string
strcasecmp — Compare strings, case-insensitively
strchr — Alias ​​for the strstr() function that returns a portion of a string by comparison
strcmp — Compare string sizes
strcoll – Size comparison of strings based on local settings
strcspn — Returns the value of the length of consecutive non-matching characters
strip_tags — Remove HTML and PHP code from a string
stripcslashes — Unescaping strings processed by the addcslashes() function
stripos — Find and return the position of the first match, matches are not case sensitive
stripslashes — Anti-escape the strings processed by the addslashes() function
stristr — Returns parts of a string by comparison, case-insensitive comparisons
strlen — Get the encoded length of a string
strnatcasecmp — Compare strings using natural sorting, case-insensitive
strnatcmp — Size comparison of strings using natural ordering
strncasecmp — Compare the first N characters of a string, case-insensitive
strncmp — Compare the size of the first N characters of a string
strpbrk — Return parts of a string by comparison
strpos — Find and return the position of the first match
strrchr — Returns parts of a string by comparing from back to front
strrev — Reverse all letters in a string
strripos — Search backwards and return the position of the first match, matching is not case-sensitive
strrpos – searches backward and returns the position of the first match
strspn — Match and return the value of the length of consecutive occurrences of characters
strstr — Returns parts of a string by comparison
strtok — Split a string using specified characters
strtolower — Convert a string to lowercase
strtoupper – Convert a string to uppercase
strtr — compare and replace strings
substr_compare — Compare strings after truncation
substr_count — Count the number of occurrences of a certain character segment in a string
substr_replace — Replace some characters in a string
substr — intercept a string
trim — remove whitespace or specified characters on both sides of a string
ucfirst — Convert the first letter of the given string to uppercase
ucwords — Capitalize the first letter of each English word in the given string
vfprintf — Return data as required and write directly to the document stream
vprintf — display data as required
vsprintf — Returns data as required, but does not output
wordwrap — Split a string according to a certain character length

The above has introduced a summary of PHP string processing functions, including aspects of it. I hope it will be helpful to friends who are interested in PHP tutorials.