The process of learning PHP, sorting out some of the commonly used functions, which are string functions.
Header ("Content-type:text/html;charset=utf-8");
Delete both sides (single-sided) spaces or other pre-defined characters
$str = "# #hello world@@";
Echo Trim ($str, ' #,@ '). "
"; Hello World
Echo LTrim ($str, ' # '). "
"; Hello world@@
Echo RTrim ($str, ' @ '). "
"; # #hello World
/* CHOP () is an alias for RTrim () */
Returns the directory portion of the path
Echo dirname ("c:/testweb/home.php"). "
"; C:/testweb
/** string generation and conversion */
Fills a string into the specified string
$str = "Hello World";
Echo Str_pad ($str, ".", Str_pad_both). "
"; ..... hello world .....
Echo Str_pad ($str, ".", Str_pad_left). "
"; .... Hello World
Echo Str_pad ($str, ".", Str_pad_right). "
"; Hello world .....
Reusing the specified string
Echo str_repeat (".", 13). "
"; //.............
/* 13 is the number of repetitions */
Splits a string into an array (containing spaces, a space of 1 characters)
$str = "My name is Junjun Liu";
$str 1 = str_split ($STR, 3);
Print_r ($str 1); Array ([0] = my [1] = nam [2] = = e I [3] = = S J [4] = Unj [5] = = UN [6] = Liu)
Invert string
$str = "Imagecreatetruecolor";
echo Strrev ($STR). "
"; Roloceurtetaercegami
To split a string by a specified length
$STR = "An example on a long word is:supercalifragulisticlasdkjflasdjfalsdkakd";
Echo WordWrap ($str, 20, "
");
Randomly scrambles all the characters in a string (the number is disrupted by the time-interval symbol)
$str = "A1,B2,C3";
echo Str_shuffle ($STR). "
"; 1,ca32,b (Random one)
Parsing a string into a variable
$str = "First=value&arr[]=foo+bar&arr[]=baz";
Parse_str ($STR);
echo $first. "
"; Value
echo $arr [0]. "
"; Foo Bar
echo $arr [1]. "
"; Baz
Print_r ($arr); Array ([0] = foo Bar [1] = baz)
Parse_str ("Id=23&name=john%20adams", $myArray);
Print_r ($myArray); Array ([id] = [name] = John Adams)
Format numbers with thousand-bit groups
Echo Number_format ("1000000"); 1,000,000
Echo Number_format ("1000000", 2); 1,000,000.00
Echo Number_format ("1000000", 2, ",", "."); 1.000.000,00
Uppercase and lowercase conversions
echo strtolower (' NAME '); Name
echo strtoupper (' name '); NAME
echo Ucfirst (' My name is Junjun Liu '); My name is Junjun Liu
echo ucwords (' My name is Junjun Liu '); My Name is Junjun Liu
HTML Associative tags
Convert a string to an HTML entity
$str = "John & ' Adams '";
Echo htmlentities ($str, Ent_compat); John & ' Adams '
Predefined word representable HTML encoding
Htmlspecialchars ($STR);
echo "
";
Replace \ r and enter in the string
tags for line-wrapping output
$string = "this\r\nis\n\ra\nstring\r";
echo nl2br ($string);
/**
* This
* IS
* A
* String
*/
Peel off the html,xml,php label
$str = "ASDASD
Woaini
";
echo Strip_tags ($STR); Asdasdwoaini
echo "
";
Adds a backslash to an escaped character in a string before the specified character
$str = "Hello, My name is John Adams.";
Echo addcslashes ($str, ' m '); Hello, \my Na\me is John Ada\ms
Remove Addcslashes Backslash
echo stripcslashes ($STR); Hello, my name is John Adams.
echo " ";
To add a backslash before specifying a predefined character
$str = "Who ' s John ad\ams?";
$str = Addslashes ($STR);
Echo $str; Who\ ' s John Adams?
Remove backslashes
echo stripslashes ($STR). "
"; Who ' s John Adams?
Add backslashes before certain predefined characters in the string (all characters are escaped)
$str = "Hello World". (Can you hear me?) ";
echo Quotemeta ($STR). "
"; Hello world\.\ (Can you hear me\?\)
ASCII return character
Echo Chr (34); Returns
Returns the ASCII value of the first character in a string
Echo Ord (ABC); 97
echo "
";
/** string comparison */
/*
* 1: Former large
*-1: latter large
* 0: Equal before and after
*/
echo "Case-insensitive comparison of two strings:". STRCASECMP ("abc", "Abd"). "
"; -1
echo "Case comparison two strings:". strcmp ("Abd", "Abd"). "
"; 1
echo "Case comparison between two strings:". strncmp ("ABCD", "ABCC", 2). "
"; 0/* 2 is the comparison of the first n string size */
echo "Case-insensitive comparison of two strings:". STRNCASECMP ("ABCD", "ABCC", 4). "
"; 1
echo "Differentiates size (in natural order) by writing to compare two strings:". STRNATCMP ("ABC2", "ABC12"). "
"; -1
echo "does not differentiate between sizes (in natural order) by writing comparisons between two strings:". STRNATCASECMP ("Abc8", "ABC12"). "
"; -1
/* String cutting and stitching */
Divide a string into small chunks (spaces also count)
$str = "Hello World Hello World";
Echo Chunk_split ($STR, 2, "#"); He#ll#o #wo #rl#d #he #ll#o #wo #rl#d#
Cut string
$first _token = strtok ('/something ', '/');
$second _token = strtok ('/');
Var_dump ($first _token); String (9) "Something"
Var_dump ($second _token); BOOL (FALSE)
Var_dump ($first _token, $second _token);(print two variables simultaneously)
$str = "This is an/example string";
$tok = Strtok ($str, "/"); This was an
Echo $tok;
$str = "Thisisan/example string";
$tok = Strtok ($str, "/"); Thisisan
Echo $tok;
Use one string to split another string for a flag
$data = "Foo:*:1023:1000::/home/foo:/bin/sh";
List ($user, $pass, $uid, $gid, $gecos, $home, $shell) = Explode (":", $data);
Echo $user; Foo
Echo $pass; // *
Concatenate array values with a subscription character into a string
$array = Array (' LastName ', ' email ', ' phone ');
$a = Implode (",", $array);
echo $a; Lastname,email,phone
Intercept string
$str = "ABSADF";
Echo substr ($str, 2, 3); Sad
Echo substr ($str, -4,-1);//sad
/* string Find and Replace */
String substitution operation, case-sensitive str_replace (changed font, changed strings, original string)
$str = "1,2,3:4,5:6";
Echo Str_replace (",", ":", $str). "
"; 1:2:3:4:5:6
echo str_replace (Array (",", ":"), ";", $str). "
"; 1;2;3;4;5;6
echo str_replace (Array (",", ":"), Array (";", "#"), $str). "
"; 1;2;3#4;5#6
String substitution operation, case insensitive
$str = "ABCDEFG";
Echo str_ireplace ("ABC", "XYZ", $STR); Xyzdefg
Counts the number of occurrences of a string in another string Substr_count (search in this string, the string to be searched, the position at which to start the offset, the maximum position of the specified offset)
$str 1 = "name";
$str 2 = "My name Isname name";
Echo Substr_count ($str 2, $str 1); 2
Replace a segment in a string with another string
$var = ' abcdefgh:/mnrpqr/';
echo "Original: $var \ n "; original:abcdefgh:/mnrpqr/
/* These two examples use "Bob" to replace the entire $var. */
Echo substr_replace ($var, ' Bob ', 0). "
\ n "; Bob
Echo substr_replace ($var, ' Bob ', 0, strlen ($var)). "
\ n "; Bob
/* insert "Bob" at the beginning of the $var. */
Echo substr_replace ($var, ' Bob ', 0, 0). "
\ n "; bobabcdefgh:/mnrpqr/
/* The following two examples use "Bob" to replace "MNRPQR" in $var. */
Echo substr_replace ($var, ' Bob ', 10,-1). "
\ n "; abcdefgh:/bob/
Echo substr_replace ($var, ' Bob ',-7,-1). "
\ n "; abcdefgh:/bob/
/* Remove "MNRPQR" from the $var. */
Echo Substr_replace ($var, ", 10,-1). "
\ n "; abcdefgh://
Returns two string similarity degrees
$str 1 = "ABCDEFGADFSA";
$str 2 = "ACDRGWSAASDF";
Echo ((Similar_text ($str 1, $str 2)/strlen ($str 1)) *100). " %"."
"; 58.333333333333%
String Lookup
$str = "Zhangsan";
Echo strstr ($str, "a"). "
"; Angsan from the front to find where a appears and intercept to the last (default false) Alias: STRCHR ()
Echo strstr ($str, "a", true). "
"; Zh from the front to find where a appears and intercept forward
Echo strrchr ($str, "a"). "
"; An A from behind and intercept to the last
Echo Strpos ($str, "a"). "
"; 2 Gets the position of the first occurrence of a string
Echo Strpos ($str, "a", 3). "
"; 6 starting from 3 position gets the location of the string occurrence a
Echo Strrpos ($str, "a"). "
"; 6 Gets the position of the last occurrence of a in a string
Converts a specified character
$trans = Array ("Hello" = "hi", "hi" = "Hello");
echo strtr ("Hi all, I said hello", $trans); Hello all, I said hi
Echo strtr ("Baab", "AB", "01"); 1001
$trans = Array ("AB" = "01");
Echo strtr ("Baab", $trans); Ba01
/*
* STRSTR (): Case sensitive
* STRISTR (): Case insensitive
*/
/*
* Strpos (): Case sensitive
* Stripos () is case insensitive
* Strrpos (): Case sensitive
* Strripos (): Case insensitive
*
*/
Returns the length of the first string in the specified character set that is present in the computed strings.
$var = strspn ("The answer to the 128th question.", "1234567890");
Echo $var; 2 because ' 42 ' is a continuous character that all characters in the first paragraph of the subject are present in ' 1234567890 '.
Gets the length of the starting substring of the mismatched matte
$a = strcspn (' abcd ', ' Apple '); Var_dump ($a); Int (0)
$b = strcspn (' abcd ', ' banana '); Var_dump ($a); Int (0)
$c = strcspn (' Hello ', ' l '); Var_dump ($c); Int (2)
$d = strcspn (' Hello ', ' world '); Var_dump ($d); Int (2)
/* String Statistics */
Statistics string contains the number of words (the third argument????????????????????????? )
$str = "My name is John";
echo Str_word_count ($STR); 4
Print_r (Str_word_count ($STR, 1)); Array ([0] = My [1] = = Name [2] = = [3] = John)
Print_r (Str_word_count ($STR, 2)); Array ([0] = My [3] = = Name [8] = = [one] = John)
Statistical string length
$STR = ' ab CD ';
echo strlen ($STR); 7
Statistic string All letters occurrences (0,255), number of occurrences of each character, and the number of occurrences of the corresponding ASCII code value
$str = "Aaaaasdfasdfwer;dlfgjjpoertuodbldbnlskjl;asfjoiwertowitwo";
echo "
";
Print_r (Count_chars ($STR));
echo "
";
Md5
$str = "hello4521";
echo MD5 ($STR); 5af267d811a324fd640b7ad2199dfe14
echo " ";
/*
function GetMd5 ($STR) {
return MD5 (MD5 ($s). Tri ");
}
*/
Md5_file ()
$str = "Ly.db";
echo Md5_file ($STR); 2f2b2262ed0732d497c90bf62af96240
The above describes the PHP commonly used functions-string, including PHP, string aspects of the content, I hope the PHP tutorial interested in a friend helpful.
