Summary of common functions of PHP

Mathematical functions
1.abs (): Absolute value
$abs = ABS (-4.2); 4.2 Numeric Absolute number
2.ceil (): Into a method to take the whole
echo ceil (9.999); 10 floating point number in one rounding
3.floor (): Rounding off the Rounding method
echo Floor (9.999); 9 floating-point numbers directly out of the decimal part
4.fmod (): floating-point number
5.pow (): Returns the number of n-th square
Echo Pow (-1, 20); 1 Base number |n quadratic value
6.round (): floating-point rounding
Echo Round (1.95583, 2); 1.96, a value | How many bits are reserved after the decimal point, the default is 0 rounded results
7.SQRT (): Seek square root
echo sqrt (9); 3 square root of the prescribed number
8.max (): Ask for maximum value
echo Max (1, 3, 5, 6, 7); 7
Returns the maximum value of multiple numbers or arrays
echo Max (Array (2, 4, 5)); 5
9.min (): Minimum value
Input: multiple numbers or arrays
Output: Returns the minimum value
10.mt_rand (): Better random number
Input: Min | max, output: Random number returns the value in the range
echo Mt_rand (0,9);//n
11.rand (): Random number input: Min | max, output: Random number returns the value in the range
12.pi (): Get pi Value

To go to a space or other character:
13.trim (): Remove spaces or other predefined characters at each end of a string
Input: Target string return value: Cleared string
14.rtrim (): Remove whitespace or other predefined characters to the right of the string
15.chop (): Alias for RTrim ()
16.ltrim (): Remove space or other predefined characters to the left of the string
17.dirname (): Returns the directory portion of the path
Echo dirname ("c:/testweb/home.php"); C:/testweb
Input: A string containing the path return value: Returns the directory portion of the file path
String generation and conversion:
18.str_pad (): Fills a string with the specified length
Input: string to fill | The length of the new string | The string to use for padding, which is blank by default
Output: String after completion
19.str_repeat (): repeating the specified string
Echo str_repeat (".", 13); String to repeat | The number of times a string will be repeated 13 points
20.str_split (): Splitting a string into an array
Print_r (Str_split ("Hello"));
Input: String to be split | The length of each array element, default 1
Output: Array of strings after splitting
21.strrev (): Invert string
Echo Strrev ("Hello world!"); !dlrow Olleh
Output: String after reverse order of target string
22.wordwrap (): String wrapping with a specified length
Input: Target string | maximum width
Output: New string after wrapping
23.str_shuffle (): Randomly disrupts all characters in a string
Echo str_shuffle ("Hello World");
Input: Target string sequential output: scrambled string
24.PARSE_STR (): Parsing a string into a variable
Input: String to parse | The array name of the stored variable
Output: return array ([id] = [name] = John Adams)
25.number_format (): Formatting numeric input by thousands grouping: number to format | Specifies how many decimals | Specifies a string to use as a decimal point | Specifies a string to use as a thousands separator
Output: 1,000,000 1,000,000.00 1.000.000,00
Case conversion:
26.strtolower (): string converted to lowercase
Echo strtolower ("Hello world!");
Target String Lowercase string
27.strtoupper (): string converted to uppercase
Echo strtoupper ("Hello world!");
Output: Uppercase string
28.ucfirst (): Capitalize the first letter of the string
echo ucfirst ("Hello World"); Hello World
29.ucwords (): string each word first character to uppercase
echo ucwords ("Hello World"); Hello World
HTML Tag associations:
30.htmlentities (): Convert character to HTML entity
31.htmlspecialchars (): Predefined word representable HTML encoding
32.NL2BR (): \ n escaped as <br> label
Echo nl2br ("One line.\nanother line.");
Output: Processed string
33.strip_tags (): Stripping HTML, XML, and PHP tags
Echo strip_tags ("Hello <b>world!</b>");
34.addcslashes (): Adds a backslash to an escaped character in a string before the specified character
Input: Target string | Specify a specific character or range of characters
35.stripcslashes (): Remove backslash added by addcslashes ()
Echo stripcslashes ("Hello, \my Na\me is Kai ji\m.");
Destination string Hello, my name is Kai Jim.
36.addslashes (): Add a backslash before specifying a predefined character
$str = "Who ' s John Adams?";
echo addslashes ($STR);
Output: "\" and null in the target string are escaped
37.stripslashes (): Remove the escape character added by Addslashes ()
Echo stripslashes ("who\ ' s John Adams?"); Clear escape sign who's John Adams?
38.quotemeta (): Add a backslash before some of the predefined characters in the string
39.CHR (): Returns the character from the specified ASCII value
Echo Chr (052); ASCII value returns the corresponding character
40.ord (): Returns the ASCII value of the first character of a string
echo ord ("Hello"); The ASCII value of the first character of a string
string comparison:
41.STRCASECMP (): Case-insensitive comparison of two strings
echo strcasecmp ("Hello world!", "Hello world!");
Input: Two target string output: Big 1| etc 0| Small-1
42.STRCMP (): Case-sensitive comparison of two strings
43.STRNCMP (): Compares the first n characters of a string, case sensitive
Call: int strncmp (String $str 1, String $str 2, int $len)
44.STRNCASECMP (): Compares the first n characters of a string, not case-sensitive
Call: int strncasecmp (String $str 1, String $str 2, int $len)
45.STRNATCMP (): Natural order Method compares string length, case-sensitive
Call: int strnatcmp (String $str 1, String $str 2)
Input: Target string
46.STRNATCASECMP (): Natural order Method compares string length, case-insensitive
Call: int strnatcasecmp (String $str 1, String $str 2)
String cutting and splicing:
47.chunk_split (): Dividing a string into small chunks
Call: Str chunk_split (str $body [, int $len [, str $end]]
Input: $body target string, $len length, $str insertion terminator output: Split string
48.strtok (): Cut string
Call: Str strtok (str $str, str $token)
Target string $str, $token for flag cut returns the cut string
49.explode (): Use one string to split another string for a flag
Call: Array explode (str $sep, str $str [, int $limit])
Input: $sep as a delimiter, $str the target string, $limit returns the array with a maximum number of elements output: The array formed after the string is split
50.implode (): joins, concatenate array values into strings with subscription characters
Call: String implode (String $glue, array $pieces)
$glue default, connect directly with "
51.SUBSTR (): Intercept string
Call: String substr (string $string, int $start [, int $length])
String Lookup substitution:
52.str_replace (): String substitution operation, case-sensitive
Call Mix Str_replace (Mix $search, Mix $replace, Mix $subject [, int & $num])
Input: $search Find the string, $replace the replacement string, $subject looked up string, & $num output: Returns the result of the substitution
53.str_ireplace () string substitution operation, case insensitive
Call: Mix Str_ireplace (Mix $search, Mix $replace, Mix $subject [, int & $count])
Input: $search find string, $replace replacement string, $subject,& $num output: Returns the replaced result
54.substr_count (): Counts the number of occurrences of a string in another string
Call: int Substr_count (String $haystack, string $needle [, int $offset = 0 [, int $length]])
55.substr_replace (): Replaces a string in another string
Call: Mixed Substr_replace (mixed $string, string $replacement, int $start [, int $length])
56.similar_text (): Returns the number of identical characters in two strings
Call: int Similar_text (str $str 1,str $str 2)
Input: Two strings for comparison
Output: XXX, the same number of characters
57.STRRCHR (): Returns a string in another string where the last occurrence of the position begins at the end of the string
Call: String STRRCHR (String $haystack, mixed $needle)
58.STRSTR (): Returns a string in another string starting at the end of the string
Call: String Strstr (String $str, String $needle, bool $before _needle)
59.STRCHR (): An alias of Strstr () that returns the first occurrence of a string in another string, starting at the end of the string
Call: String Strstr (String $haystack, mixed $needle [, bool $before _needle = false])
60.STRISTR (): Returns a string in another string starting at the end of the string, case-insensitive
Call: String Stristr (String $haystack, mixed $needle [, bool $before _needle = false])
61.STRTR (): Converts some characters in a string
Call: String Strtr (String $str, String $from, String $to)
62.strpos (): Find where a character in a string first appears
Call: int Strpos (String $haystack, mixed $needle [, int $offset = 0])
63.stripos (): Looks for the first occurrence of a character in a string, case-insensitive invocation: int Stripos (String $haystack, string $needle [, int $offset])
64.strrpos (): Find the last occurrence of a character in a string
Call: int Strrpos (String $haystack, string $needle [, int $offset = 0])
65.strripos (): Finds the last occurrence of a character in a string, is not case sensitive
Call: int Strripos (String $haystack, string $needle [, int $offset])
66.STRSPN (): Returns the first mask-compliant substring length in a string called: int strspn (String $str 1, String $str 2 [, int $start [, int $length]])
67.STRCSPN (): Returns the length of a string in a string that does not match mask
Call: int strcspn (String $str 1, String $str 2 [, int $start [, int $length]])
Input: $str 1 is queried, $str 2 query string, $start the character to start querying, $length is the query length output: Returns from the beginning to the first few characters
String statistics:
68.str_word_count (): Statistics string contains the number of words
Call: Mix str_word_count (str $str, [])
Input: Target string output: Number of statistics offices
69.strlen (): Statistical string length int strlen (str $str)
Input: Target string output: integer length
70.count_chars (): Count all occurrences of letters in the string (0..255) Call: Mixed Count_chars (string $string [, int $mode])
String encoding:
71.md5 (): String MD5 encoding
Array functions
Array creation:
72.array (): Generate an array
Array value or, key = = value of an array type variable
73.array_combine (): Generates an array with the value of one array as the key name and the other array value as the value
$a 1=array ("a", "B", "C", "D");
$a 2=array ("Cat", "Dog", "Horse", "Cow");
Print_r (Array_combine ($a 1, $a 2));
$a 1 to provide the key, $a 2 provides the array after the value is synthesized
74.range (): Creates and returns an array containing the elements of the specified range.
$number = range (0,50,10);
Print_r ($number);
Input: 0 is the minimum value, 50 is the maximum value, and 10 is the step output: the synthesized array
75.compact (): Creates an array of variables with parameters
Variable or array
Returns an array of variables whose value is the value of the variable named key, and the variable can also be a multidimensional array. Recursive processing
76.array_fill (): array with the given padding (value generation)
2 is the key, 3 is the number of fills, and ' Dog ' returns the completed array for the filled contents
Array merging and splitting:
77.array_chunk (): Splits an array into a new array block
An array of multidimensional arrays, which specifies that each new array contains 2 elements
78.array_merge (): Merging two or more arrays into an array
Input: Two array output: Returns the completed array
79.array_slice (): Takes a value out of the array and returns it as a condition.
Input: An array output: 1 for starting with ' Cat ', 2 for returning two elements
Array comparison:
80.array_diff (): Returns an array of difference sets for two arrays
Input: Two or more array outputs: $a 1 differs from $a2
81.array_intersect (): Returns the array output of the intersection of two or more arrays: Returns ' Dog ' and ' Horse ', $a 1 in the same place as $a2
Array Lookup substitution:
82.array_search (): Finds a value in the array, returns a key, returns no false
Input: An array output: Successful return of key name, failure to return false
83.array_splice (): Remove part of the array with other values instead
Input: One or more of the array outputs: $a 1 The removed part is complete by $a2
84.array_sum (): Returns the sum of all values in the array
Input: An array output: return and
85.in_array (): Searches the array for the given value, case sensitive
Input: value to search | Array output: TRUE/FALSE
86.array_key_exists (): Determines whether the specified key exists in an array
Input: Key name to search | array
Array pointer operations:
87.key (): Returns the key name of the array inside the pointer currently pointing to the element
88.current (): Returns the current element (cell) in the array.
89.next (): Moves the pointer to the current element to the position of the next element and returns the value of the current element
90.prev (): Moves the pointer to the current element to the position of the previous element and returns the value of the current element
91.end (): Points The inner pointer of the array to the last element and returns the value of the element (if successful)
92.reset (): Points The inner pointer of the array to the first element and returns the value of the element
93.list (): Assigns a set of variables to an array of elements
Input: $a, $b, $c the output of variables that need to be assigned: variables match values in the array, respectively
94.array_shift (): Deletes the first element in the array and returns the value of the deleted element
95.array_unshift (): Inserts one or more elements at the beginning of the array
96.array_push (): One or more elements are pressed into the array at the end
Input: Target array | Value to be pressed in return value: Returns the new array
97.array_pop (): Gets (deletes) the last element in the array
Input: $a for the target array output: Returns the remaining elements of the array
Array key-value operation:
98.shuffle (): Scrambled array, reserved key name
Input: One or more array outputs: arrays with scrambled order
99.count (): Calculates the number of cells in an array or the number of attributes in an object
Input: Array output: number of output elements
100.array_flip (): Returns an array after a key-value reversal
Output: Returns the completed array
101.array_keys (): Returns all the keys of an array, forming an array
Output: Returns an array of key names
102.array_values (): Returns all values in an array, forming an array
Output: Returns an array of key values
103.array_reverse (): Returns an array of elements in the opposite order of an element order, with key names and key values still matching
104.array_count_values (): Number of occurrences of all values in the statistics array
Output: Returns the original key value of the array as the new key name, the number of times is the new key value
105.array_rand (): Randomly extracts one or more elements from an array, note the key name!!!
$a is the target array, 1 returns the key name of the 1th element for the key name of the first element b
106.each (): Returns the current key/value pair in the array and moves the array pointer forward one step at a call to array each (array & $array)
After each (), the array pointer stays in the next cell in the array, or when the end of the array is encountered, the last cell. If you want to iterate through the array again, you must use Reset ().
Return value: The key/value pair in the current pointer position in the array and moves the array pointer forward. A key-value pair is returned as an array of four cells with the key name 0,1,key and value. Unit 0 and key contain the key name of the array cell, and 1 and value contain the data. If the internal pointer crosses the end of the array, each () returns FALSE.
107.array_unique (): Delete duplicate value, return remaining array
Input: Array input: Returns an array of No duplicates, with the key name unchanged
Array sorting:
108.sort (): Sorts the values of the given array in ascending order without preserving the key name
Output: True/false
109.rsort (): Reverse-sort an array without preserving the key name
110.110.asort (): Sort an array, keeping the index relationship
111.111.arsort (): Reverse-sort an array, keeping the index off
112.112.ksort (): Series Ordering of key names
113.113.krsort (): Reverses the array by key
114.114.natsort (): Sort elements in an array with natural order algorithm
115.115.natcasesort (): Natural sort, case insensitive
File system functions
116.fopen (): Open file or URL
$handle = fopen ("Ftp://user:[email protected]/somefile.txt", "w");
Call: Resource fopen (string filename, string mode [, bool Use_include_path [, Resource Zcontext]])
Return value: If open fails, this function returns FALSE
117.fclose (): Close an open file pointer
Output: Returns TRUE if successful, FALSE if unsuccessful
File properties
118.file_exists (): Checks whether a file or directory exists
Call: BOOL File_exists (string filename) input: Specified file or directory output: True if present, otherwise FALSE is returned
119.filesize (): Get File size
Call: int filesize (string $filename)
Output: Returns the number of bytes of file size if an error returns false and generates an E_warning level error
120.is_readable (): Determines whether a given file is readable
Call: BOOL Is_readable (string $filename) output: Returns TRUE if the file or directory specified by filename exists and is readable
121.is_writable (): Determines whether a given file is writable
Call: BOOL Is_writable (string $filename) The filename parameter can be a directory name that allows for a writable check
Output: Returns TRUE if the file exists and is writable.
122.is_executable (): Determines whether a given file is executable
Call: BOOL Is_executable (string $filename) output: Returns TRUE if the file exists and is executable
123.filectime (): Gets the creation time of the file
Call: int Filectime (string $filename) Output: Time is returned as a Unix timestamp, False if an error is returned
124.filemtime (): Gets the file modification time
int Filemtime (string $filename)
Output: Returns the last time the file was modified and returns FALSE on error. Time is returned as a UNIX timestamp
125.fileatime (): Gets the last access time for the file
Call: int Fileatime (string $filename)
Output: Returns the last time the file was accessed and returns False if an error occurs. Time is returned as a Unix timestamp.
126.stat (): Get most of the file property values
Call: Array stat (string $filename output: Returns the statistics for the file specified by the filename
File operations
127.fwrite (): Write file
Call: int fwrite (resource handle, string string [, int length])
Output: Writes the contents of the string to the file pointer handle. If length is specified, the write stops when the length byte is written or after the string is written, depending on what kind of situation is encountered first
128.fputs (): Ibid.
129.fread (): Read file
Called: string fread (int handle, int length) handle from the file pointer, reads up to length of bytes
130.feof (): Detects if the file pointer is at the end of the file
Call: BOOL Feof (resource handle) Output: Returns an error (including the socket timeout) if the file pointer goes to EOF or returns True if an error occurs, otherwise returns FALSE
131.fgets (): Reads a row from the file pointer
Call: string fgets (int handle [, int length]) output: Reads a row from a file pointed to by handle and returns a string that is up to length-1 bytes in length. Encounters a newline character (included in the return value), EOF, or has read lengt H-1 bytes after the stop (see first encounter that situation). If length is not specified, the default is 1 K, or 1024 bytes.
132.FGETC (): Reading characters from the file pointer
Input: String fgetc (Resource $handle) output: Returns a String containing a character that is obtained from the file pointed to by handle. Returns FALSE if EOF is encountered.
133.file (): reads the entire file into an array
Call: Array file (string $filename [, int $use _include_path [, Resource $context]])
Output: Each cell in the array is the corresponding line in the file, including the newline character. FALSE if failure file () returns
134.readfile (): Output a file invocation: int ReadFile (string $filename [, bool $use _include_path [, Resource $context]])
Output: Reads a file and writes to the output buffer. Returns the number of bytes read from the file. FALSE if error is returned
135.file_get_contents (): reads the entire file into a string
echo file_get_contents (' http://www.baidu.com ');
Call: String file_get_contents (String $filename [, bool $use _include_path [, Resource $context [, int $offset [, int $maxl EN]]]) 136.file_put_contents (): Writes a string to the file
File_put_contents (' 1.txt ', ' AA ');
Call: int file_put_contents (String $filename, String $data [, int $flags [, Resource $context]])
Output: The function returns the number of bytes written to the data in the file
137.ftell (): Returns the location of the file pointer read/write
Call: Int Ftell (Resource $handle) output: Returns the position of the file pointer specified by handle, which is the offset in the file stream
138.fseek (): Locating in the file pointer
called: int fseek (resource $handle, int $offset [, int $whence]) output: Success returns 0; otherwise returns-1
139.rewind (): Rewind the position of the file pointer
Call: BOOL Rewind (Resource $handle) return value: Returns TRUE if successful, FALSE if failed
140.flock (): Lightweight to perform file lock
Call: BOOL Flock (int $handle, int $operation [, int & $wouldblock]) output: Returns TRUE if successful, FALSE if failed
Directory
141.basename (): Returns the file name portion of the path
Call: String basename (String $path [, string $suffix]) output: Gives a string containing a full path to a file, this function returns the base file name. If the file name ends in suffix, then this part will be removed as well.
142.dirname (): Returns the directory portion of the path
Call: String DirName (String $path) output: Gives a string containing a full path to a file, which returns the name of the directory after removing the filename
143.pathinfo (): Returns information for file path
Call: Mixed PathInfo (string $path [, int $options]) returns an associative array containing information about path
144.opendir (): Open Directory Handle
Call: Resource Opendir (String $path [, Resource $context]) return value: Returns the resource of the directory handle if successful, and false if it fails
145.readdir (): Reads entries from the directory handle
Call: String Readdir (Resource $dir _handle) return value: Returns the file name of the next file in the directory. File names are returned in a sort order in the file system
146.closedir (): Close directory handle
Call: void Closedir (Resource $dir _handle) to close the directory stream specified by Dir_handle. Stream must be opened before Opendir () 147.rewinddir (): Rewind the Directory handle
Call: void Rewinddir (Resource $dir _handle) output: Resets the Dir_handle specified directory stream to the beginning of the directory
148.mkdir (): New directory
mkdir (' 123 ');
Call: bool MkDir (string $pathname [, int $mode [, bool $recursive [, Resource $context]]) output: Attempt to create a new directory specified by pathname
149.rmdir (): Delete directory
RmDir (' 123 ');
Call: BOOL RmDir (string $dirname) output: Attempts to delete the directory specified by DirName. The directory must be empty and have the appropriate permissions. Returns true if successful, FALSE if unsuccessful
150.unlink (): Delete file
Call: BOOL Unlink (string $filename) output: delete filename. Similar to the unlink () function of Unix C. Returns TRUE if successful, FALSE if unsuccessful
151.copy (): Copy file
Copy (' index.php ', ' Index.php.bak ');
Call: BOOL Copy (String $source, String $dest) Output: Copies the file from source to Dest. Returns true if successful, FALSE if unsuccessful
152.rename (): Rename a file or directory
Rename (' Tx.txt ', ' txt.txt ');
Call: bool Rename (string $oldname, String $newname [, resource $context]) output: Returns TRUE if successful, FALSE if failed
Uploading and downloading of files
153.is_uploaded_file (): Determine if the file was uploaded via HTTP post
Call: BOOL Is_uploaded_file (String $filename)
154.move_uploaded_file (): Move uploaded files to a new location
Call: BOOL Move_uploaded_file (string $filename, String
Time function
155.time (): Returns the current Unix timestamp time (); Call: int time (void) Output: Returns the number of seconds since the Unix era (00:00:00 GMT, January 1, 1970) to the current
156.mktime (): Gets a date for the Unix timestamp
Mktime (0, 0, 0, 4, 25, 2012);
Call: int mktime ([int $hour [, int $minute [, int $second [, int $month [, int $day [, int $year [, int $is _DST]]] 157.date (): Format a local time/date
Date (' Y year m D Day H:i:s ');
Call: string Date (string $format [, int $timestamp])
Output: September 10, 2016 20:45:54
158.checkdate (): Validation of a trellis-high-date call: bool Checkdate (int $month, int $day, int $year) output: Returns TRUE if the given date is valid, otherwise FALSE
159.date_default_timezone_set (): Sets the default time zone for all datetime functions in a script
Date_default_timezone_set (' PRC ');
Call: BOOL Date_default_timezone_set (string $timezone _identifier)
Return value: Returns FALSE if the Timezone_identifier parameter is not valid, otherwise returns TRUE.
160.getdate (): Get Date/Time information call: Array getdate ([int $timestamp])
Output: Returns an associative array that contains date information, based on timestamp. If no timestamp is given, the current local time is considered
161.strtotime (): Resolves the datetime description of any English text to a Unix timestamp
162.microtime (): Returns the current Unix timestamp and number of microseconds calls: Mixed Microtime ([bool $get _as_float])
Other commonly used:
163.intval (): Gets the integer value of the variable called: int intval (mixed $var [, int $base = 10]) returns the integer value of the variable var by using the specified binary base conversion (default is decimal). Intval () cannot be used with object, otherwise it will produce an ENOTICE error and returns 1.
var: the number of values to convert to integers
Base: The binary used by the conversion
Return value: Returns the integer value of Var on success and returns 0 on failure. An empty array returns 0, and a non-empty array returns 1.
Related functions of the PDO class prepare () Execute () fetch ()
Regular Expressions-metacharacters
Metacharacters and its matching range
\d matches any decimal number, equivalent to: [0-9] \d matches any number except a decimal number, equivalent to: [^0-9] \s: Matches a white space character, equivalent to: [\n\f\r\t\v] \s: matches any character except the white space character, equivalent to [^\n\f\r\t \V]
\w matches any number, letter, and underscore equivalent to: [0-9a-za-z] \w matches any character except letters, numbers, and underscores, equivalent to: [^0-9a-za-z_] [] 1) to denote a range. 2) match any one of the atoms defined in the brackets [^]: the ^ (caron) Inside the brackets: means match any one of the atoms defined in the brackets.
Limit times

• Matches 0, 1, or more atoms before it, equivalent to: {0,} + matches 1 or more times before the atom, equivalent to: {1,}? Matches 0 or 1 times its former atom, equivalent to: {0,1} {n} indicates that the atom before it is exactly n times, equivalent to: {N,} indicates that the atom before it appears at least n times, up to No Limit {M,n} indicates that the atom before it appears at least m times, up to N times
  Other
  . Match any character except line break (\ n) "Windows also matches \f\r"
  | Two or more branches select "Lowest priority"
  ^ matches the starting position of the input character
  $ match the end position of the input character
  \b Match word boundaries
  \b Matches non-word boundaries
  () 1) A mode unit that makes up a large atom of several small atoms. 2) can change the priority level

Summary of common functions of PHP