Review of common functions in PHP

The following is a detailed analysis of common functions in PHP. For more information, see array_change_key_case. the returned string key names are all lowercase or upper-case arrays.
Array_chunk-divide an array into multiple
Array_combine-creates an array and uses the value of one array as its key name, and the value of another array as its value
Array_count_values-count the number of occurrences of all values in the array
Array_diff_assoc-calculate the array's difference set with index check
Array_diff_key-use the key name to compare the difference set of the calculated array
Array_diff_uassoc-use the callback function provided by the user to perform an index check to calculate the array's difference set
Array_diff_ukey-use the callback function to compare the difference set of the calculated array with the key name
Array_diff-calculate the difference set of the array
Array_fill_keys-Fill an array with values, specifying keys
Array_fill-fill the array with the given value
Array_filter-filter elements in the array using the callback function
Array_flip-swap the keys and values in the array
Array_intersect_assoc-intersection of arrays computed by checking indexes
Array_intersect_key-use a key name to compare and calculate the intersection of arrays
Array_intersect_uassoc-returns the intersection of arrays computed by checking indexes and compares indexes with callback functions.
Array_intersect_ukey-use the callback function to compare key names to calculate the intersection of arrays
Array_intersect-calculates the intersection of arrays
Array_key_exists-check whether the given key name or index exists in the array
Array_keys-returns all the key names in the array.
Array_map-calls the callback function to the unit of the given array.
Array_merge_recursive-recursively merge one or more arrays
Array_merge-merge one or more arrays
Array_multisort-sorts multiple arrays or multi-dimensional arrays.
Array_pad-fill the array with a value to the specified length
Array_pop-bring up the last unit of the array (Out Stack)
Array_product-calculate the product of all values in the array
Array_push-push one or more units to the end of the array (into the stack)
Array_rand-randomly retrieve one or more units from the array
Array_reduce-use callback functions to iteratively simplify an array to a single value
Array_reverse-returns an array with the opposite unit order.
Array_search-search for a given value in the array. if the value is successful, the corresponding key name is returned.
Array_shift-removes elements starting with an array from the array
Array_slice-extract a segment from the array
Array_splice-removes a part of the array and replaces it with other values.
Array_sum-calculates the sum of all values in the array
Array_udiff_assoc-calculate the difference set of the array with index check and use the callback function to compare data
Array_udiff_uassoc-calculate the difference set of the array with index check, and use the callback function to compare data and indexes.
Array_udiff-use the callback function to compare data to calculate the difference set of the array
Array_uintersect_assoc-returns the intersection of arrays computed by checking indexes and compares data with callback functions.
Array_uintersect_uassoc-returns the intersection of arrays computed by checking indexes and compares data and indexes using callback functions.
Array_uintersect-calculate the intersection of arrays and use the callback function to compare data
Array_unique-Remove repeated values from the array
Array_unshift-insert one or more units at the beginning of the array
Array_values-returns all values in the array.
Array_walk_recursive-recursively applies user functions to each member in the array
Array_walk-apply user functions to each member in the array
Array-create an array
Arsort-sorts arrays in reverse order and maintains the index relationship.
Asort-sorts arrays and maintains the index relationship
Compact-create an array, including variable names and their values
Count-calculates the number of units in the array or the number of attributes in the object.
Current-returns the current cell in the array.
Each-returns the current key/value pair in the array and moves the array pointer one step forward.
End-points the internal pointer of the array to the last unit.
Extract-import the variable from the array to the current symbol table
In_array-check whether a value exists in the array
Key-get the key name from the associated array
Krsort-sort arrays in reverse order by key name
Ksort-sort the array by key name
List-assign values in the array to some variables
Natcasesort-use the "natural sorting" algorithm to sort arrays by case-insensitive letters
Natsort-sort arrays using the "natural sorting" algorithm
Next-move the internal pointer in the array to a forward position.
Alias of pos-current ()
Prev-returns the internal pointer of the array to one position.
Range-create an array containing the specified range units
Reset-point the internal pointer of the array to the first unit
Rsort-reverse sorting of arrays
Shuffle-disrupt the array
Alias of sizeof-count ()
Sort-sort arrays
Uasort-sort the values in the array using the user-defined comparison function and maintain the index Association
Uksort-sort the key names in the array using the user-defined comparison function
Usort-sort the values in the array using the user-defined comparison function
Call_user_method_array-call a user method and pass the parameter array (obsolete)
Call_user_method-call the user method for a specific object (obsolete)
Class_exists-check whether the class is defined
Get_class_methods-returns an array composed of class method names.
Get_class_vars-returns an array composed of the default attributes of the class.
Get_class-class name of the returned object
Get_declared_classes-returns an array composed of the names of defined classes.
Get_declared_interfaces-returns an array containing all declared interfaces.
Get_object_vars-returns an associated array composed of object attributes.
Get_parent_class-return the parent class name of the object or class
Interface_exists-check whether the interface has been defined
Is_a-if the object belongs to this class or the class is the parent class of this object, TRUE is returned.
Is_subclass_of-if this object is a subclass of this class, TRUE is returned.
Method_exists-check whether the class method exists
Property_exists-check whether the object or class has this attribute
Checkdate-verify a greaguri date
Date_default_timezone_get-gets the default time zone used by all the datetime functions in a script.
Date_default_timezone_set-sets the default time zone used for all date and time functions in a script.
Date_time_set-Sets the time
Date_timezone_get-Return time zone relative to given DateTime
Date_timezone_set-Sets the time zone for the DateTime object
Date-format a local time/date
Getdate-get date/time information
Gettimeofday-get current time
Gmdate-format a GMT/UTC date/time
Gmmktime-obtain the UNIX timestamp of the GMT Date
Gmstrftime-format GMT/UTC time/date based on region settings
Idate-format the local time and date as an integer
Localtime-get local time
Microtime-returns the current Unix timestamp and number of microseconds
Mktime-obtain the Unix timestamp of a date
Strftime-format local time/date based on region settings
Strptime-parse the date/time generated by strftime ()
Strtotime-parses the date and time descriptions of any English text into Unix timestamps
Time-returns the current Unix timestamp
Chdir-Change Directory
Chroot-change root directory
Dir-directory class
Closedir-close directory handle
Getcwd-get the current working directory
Opendir-Open Directory handle
Readdir-read entries from the directory handle
Rewinddir-reverse directory handle
Scandir-list files and directories in a specified path
Basename-part of the file name in the returned path
Chgrp-change the group to which the file belongs
Chmod-change file mode
Chown-change the file owner
Clearstatcache-clear the file status cache
Copy-copy an object
Delete-see unlink () or unset ()
Dirname-directory part of the returned path
Disk_free_space-return the available space in the directory
Disk_total_space-returns the total disk size of a directory
Diskfreespace-disk_free_space () alias
Fclose-close an opened file pointer
Feof-test whether the file pointer is at the end of the file
Fflush-outputs Buffered content to a file
Fgetc-read characters from the file pointer
Fgetcsv-read a row from the file pointer and parse the CSV field
Fgets-read a row from the file pointer
Fgetss-read a row from the file pointer and filter out the HTML tag
File_exists-check whether the file or directory exists
File_get_contents-read the entire file into a string
File_put_contents-write a string to a file
File-read the entire file into an array
Fileatime-the last time the file was accessed
Filectime-get the inode modification time of the file
Filegroup-the group for obtaining files
Fileinode-get the inode of the file
Filemtime-get file modification time
Fileowner-get the file owner
Fileperms-get file permissions
Filesize-get the file size
Filetype-get file type
Flock-lightweight consultation file locking
Fnmatch-match the file name in the pattern
Fopen-open a file or URL
Fpassthru-all the remaining data at the output file pointer
Fputcsv-format rows as CSV and write file pointers
Fputs-fwrite () alias
Fread-read files (which can be safely used for binary files)
Fscanf-format input from file
Fseek-locate in file pointer
Fstat-get file information through the opened file pointer
Ftell-returned file pointer read/write location
Ftruncate-truncates a file to a specified length
Fwrite-write a file (which can be safely used for binary files)
Glob-find the file path that matches the pattern
Is_dir-determine whether the given file name is a directory
Is_executable-determine whether a given file name can be executed
Is_file-determine whether the given file name is a normal file
Is_link-determine whether a given file name is a symbolic connection
Is_readable-determine whether the given file name is readable
Is_uploaded_file-determines whether the file is uploaded through http post.
Is_writable-determine whether a given file name can be written
Is_writeable-is_writable () alias
Lchgrp-Changes group ownership of symlink
Lchown-Changes user ownership of symlink
Link-create a hard connection
Linkinfo-get the connection information
Lstat-displays information about a file or symbolic connection.
Mkdir-create a directory
Move_uploaded_file-move the uploaded file to a new location
Parse_ini_file-parse a configuration file
Pathinfo-returned file path information
Pclose-disable process file pointer
Popen-open process file pointer
Readfile-output a file
Readlink-returns the target to which the symbolic connection points.
Realpath-returns the normalized absolute path name.
Rename-rename a file or directory
Rewind-position of the inverted file pointer
Rmdir-Delete directory
Set_file_buffer-stream_set_write_buffer () alias
Stat-file information
Symlink-create a symbolic connection
Tempnam-create a file with a unique file name
Tmpfile-create a temporary file
Touch-set the file access and modification time
Umask-change the current umask
Unlink-delete an object
Mail-send email
Abs-absolute value
Acos-arccosine
Acossh-inverse hyperbolic cosine
Asin-arcsin
Asinh-Inverse hyperbolic sine
Atan2-arc tangent of two parameters
Atan-arc tangent
Atanh-antihyperbolic tangent
Base_convert-convert a number between any hexadecimal values
Bindec-Convert binary to decimal
Ceil-integer in one method
Cos-cosine
Cosh-hyperbolic cosine
Decbin-decimal to binary
Dechex-decimal to hexadecimal
Decoct-decimal to octal
Deg 2rad-converts degrees to radians
Exp-calculate the e index
Expm1-returns exp (number)-1. even if the number value is close to zero, the exact result can be calculated.
Floor-rounding
Fmod-returns the remainder of the floating point number of the division.
Getrandmax-display the maximum possible values of a random number
Hexdec-hexadecimal conversion to decimal
Hypot-calculates the oblique edge length of the angular triangle
Is_finite-determine if it is a finite value
Is_infinite-determines if it is an infinite value
Is_nan-determine whether it is a valid value
Lcg_value-composite linear coequal generator
Log10-base-10 logarithm
Log1p-return log (1 + number), even when the number value is close to zero, the accurate result can be calculated.
Log-Natural logarithm
Max-find the maximum value
Min-find the minimum value
Mt_getrandmax-display the maximum possible value of a random number
Mt_rand-generate better random numbers
Mt_srand-play a better random number generator seed
Octdec-octal to decimal
Pi-obtain the circumference rate value
Pow-exponential expression
Rad2deg-converts radians to degrees.
Rand-generate a random integer
Round-rounding floating point numbers
Sin-sine
Sinh-hyperbolic sine
Sqrt-square root
Srand-broadcast the seed of the random number generator
Tan-tangent
Tanh-hyperbolic tangent
Mysql_affected_rows-obtain the number of records affected by the previous MySQL operation
Mysql_change_user-change the user logged on to the active connection
Mysql_client_encoding-name of the returned character set
Mysql_close-close MySQL connection
Mysql_connect-open a connection to the MySQL server
Mysql_create_db-create a MySQL database
Mysql_data_seek-move internal result Pointer
Mysql_db_name-get result data
Mysql_db_query-send a MySQL Query
Mysql_drop_db-discard (delete) a MySQL database
Mysql_errno-returns the numeric encoding of the error message in the previous MySQL operation
Mysql_error-return the text error message generated by the previous MySQL operation
Mysql_escape_string-escape a string for mysql_query
Mysql_fetch_array-get a row from the result set as an associated array, or number array, or both
Mysql_fetch_assoc-get a row from the result set as the associated array
Mysql_fetch_field-retrieve column information from the result set and return it as an object
Mysql_fetch_lengths-length of each output in the result set
Mysql_fetch_object-get a row from the result set as an object
Mysql_fetch_row-retrieve a row from the result set as an enumerated array
Mysql_field_flags-retrieve the flag associated with the specified field from the result
Mysql_field_len-return the length of the specified field
Mysql_field_name-field name of the specified field in the result obtained
Mysql_field_seek-set the pointer in the result set to the specified field offset.
Mysql_field_table-get the name of the table where the specified field is located
Mysql_field_type-specify the field type in the result set.
Mysql_free_result-release result memory
Mysql_get_client_info-obtain MySQL client information
Mysql_get_host_info-obtain MySQL host information
Mysql_get_proto_info-obtain MySQL protocol information
Mysql_get_server_info-obtain MySQL server information
Mysql_info-obtain the information of the last query
Mysql_insert_id-get the ID generated by the previous INSERT operation
Mysql_list_dbs-list all databases on the MySQL server
Mysql_list_fields-list fields in MySQL results
Mysql_list_processes-list MySQL processes
Mysql_list_tables-list tables in the MySQL database
Mysql_num_fields-number of fields in the result set obtained
Mysql_num_rows-number of rows in the result set
Mysql_pconnect-open a persistent connection to the MySQL server
Mysql_ping-Ping a server connection. if there is no connection, reconnect.
Mysql_query-send a MySQL Query
Mysql_real_escape_string-special characters in the character strings used in the escape SQL statement, taking into account the connected current character set
Mysql_result-get result data
Mysql_select_db-select MySQL database
Mysql_stat-get the current system status
Mysql_tablename-get the table name
Mysql_thread_id-returns the ID of the current thread
Mysql_unbuffered_query-a row that sends an SQL query to MySQL and does not obtain or cache the result.
Flush-refresh the output buffer
Ob_clean-Clean (erase) the output buffer
Ob_end_clean-Clean (erase) the output buffer and turn off output buffering
Ob_end_flush-Flush (send) the output buffer and turn off output buffering
Ob_flush-Flush (send) the output buffer
Ob_get_clean-Get current buffer contents and delete current output buffer
Ob_get_contents-Return the contents of the output buffer
Ob_get_flush-Flush the output buffer, return it as a string and turn off output buffering
Ob_get_length-Return the length of the output buffer
Ob_get_level-Return the nesting level of the output buffering mechanic
Ob_get_status-Get status of output buffers
Ob_gzhandler-ob_start callback function to gzip output buffer
Ob_implicit_flush-Turn implicit flush on/off
Ob_list_handlers-List all output handlers in use
Ob_start-Turn on output buffering
Output_add_rewrite_var-Add URL rewriter values
Output_reset_rewrite_vars-Reset URL rewriter values
Preg_grep-returns the array unit that matches the pattern.
Preg_last_error-Returns the error code of the last PCRE regex execution
Preg_match_all-perform global regular expression matching
Preg_match-regular expression matching
Preg_quote-escape regular expression characters
Preg_replace_callback-use the callback function to search and replace regular expressions
Preg_replace-search and replace a regular expression
Preg_split-use regular expressions to split strings
Session_cache_expire-Return current cache expire
Session_cache_limiter-Get and/or set the current cache limiter
Session_commit-session_write_close () alias
Session_decode-Decodes session data from a string
Session_destroy-Destroys all data registered to a session
Session_encode-encode the current session data into a string
Session_get_cookie_params-Get the session cookie parameters
Session_id-Get and/or set the current session id
Session_is_registered-Find out whether a global variable is registered in a session
Session_module_name-Get and/or set the current session module
Session_name-Get and/or set the current session name
Session_regenerate_id-Update the current session id with a newly generated one
Session_register-Register one or more global variables with the current session
Session_save_path-Get and/or set the current session save path
Session_set_cookie_params-Set the session cookie parameters
Session_set_save_handler-Sets user-level session storage functions
Session_start-Initialize session data
Session_unregister-Unregister a global variable from the current session
Session_unset-Free all session variables
Session_write_close-Write session data and end session
Ereg_replace-regular expression replacement
Ereg-regular expression matching
Eregi_replace-replace a case-insensitive regular expression
Eregi-case-insensitive regular expression matching
Split-use regular expressions to split strings into arrays
Spliti-use regular expressions to split strings into arrays without case sensitivity
SQL _regcase-generate a regular expression for matching with no size difference
Addcslashes-escape characters in strings using backslash in the C-language style
Addslashes-use a backslash to reference a string
Bin2hex-Convert binary data to hexadecimal representation
Alias of chop-rtrim ()
Chr-return the specified character
Chunk_split-splits a string into small parts
Count_chars-returns the characters used by the string.
Crc32-calculate the crc32 polynomial of a string
Crypt-One-way string encryption (hashing)
Echo-Output one or more strings
Explode-use one string to separate another 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
Html_entity_decode-Convert all HTML entities to their applicable characters
Htmlentities-Convert all applicable characters to HTML entities
Htmlspecialchars_decode-Convert special HTML entities back to characters
Htmlspecialchars-Convert special characters to HTML entities
Implode-Join array elements with a string
Join-alias implode ()
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_file-Calculates the md5 hash of a given file
Md5-Calculate the md5 hash of a string
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-Return ASCII value of character
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
Quotemeta-Quote meta characters
Rtrim-Strip whitespace (or other characters) from the end of a string
Setlocale-Set locale information
Shaw.file-Calculate the sha1 hash of a file
Sha1-Calculate the sha1 hash of a string
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_getcsv-Parse a CSV string into an array
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_word_count-Return information about words used in a string
Strcasecmp-Binary safe case-insensitive string comparison
Strchr-alias strstr ()
Strcmp-Binary safe string comparison
Strcoll-Locale based string comparison
Strcsps-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 position of first occurrence of a case-insensitive string
Stripslashes-Un-quote string quoted with addslashes ()
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 position of first occurrence of a string
Strrchr-Find the last occurrence of a character in a string
Strrev-Reverse a string
Strripos-Find position of last occurrence of a case-insensitive string in a string
Strrpos-Find position of last occurrence of a char in a string
Strsps-find length of initial segment matching mask
Strstr-Find first occurrence of a string
Strtok-Tokenize string
Strtolower-Make a string lowercase
Strtoupper-Make a string uppercase
Strtr-Translate certain characters
Substr_compare-Binary safe optionally case insensitive comparison of 2 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
Substr-Return part 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
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 using a string break character
Base64_decode-decodes data encoded with MIME base64
Base64_encode-encode data using MIME base64
Get_headers-get all headers sent by the server in response to an HTTP request
Get_meta_tags-extract all meta tag content attributes from a file and return an array
Http_build_query-request string generated after URL-encode
Parse_url-parses the URL and returns its components
Rawurldecode-decode the encoded URL string
Rawurlencode-encode the URL according to RFC 1738
Urldecode-decode the encoded URL string
Urlencode-encode a URL string
Debug_zval_dump-Dumps a string representation of an internal zend value to output
Alias of doubleval-floatval ()
Empty-check whether a variable is empty
Floatval-get the floating point value of the variable
Get_defined_vars-returns an array consisting of all defined variables.
Get_resource_type-returned resource type
Gettype-get the variable type
Import_request_variables-import GET/POST/Cookie variables to the global scope
Intval-obtains the integer of a variable.
Is_array-check whether the variable is an array
Is_binary-Finds whether a variable is a native binary string
Is_bool-check whether the variable is Boolean
Is_buffer-Finds whether a variable is a native unicode or binary string
Is_callable-check whether the parameter is a valid callable structure
Is_double-is_float () alias
Is_float-check whether the variable is floating point type
Is_int-check whether the variable is an integer
Is_integer-is_int () alias
Alias of is_long-is_int ()
Is_null-check whether the variable is NULL
Is_numeric-check whether the variable is a numeric or numeric string
Is_object-check whether the variable is an object
Alias of is_real-is_float ()
Is_resource-check whether the variable is of the resource type
Is_scalar-check whether the variable is a scalar
Is_string-check whether the variable is a string
Is_unicode-Finds whether a variable is a unicode string
Isset-check whether the variable is set
Print_r-prints easy-to-understand information about variables.
Serialize-generate a representation of a stored value
Settype-set the variable type
Strval-get the string value of the variable
Unserialize-create a PHP value from a stored representation
Unset-release given variables
Var_dump-prints information about a variable.
Var_export-string representation of the output or returned variable