PHP String Tips_PHP Tutorial

Pay attention to the use of escape characters\,",$
Pay attention to the use of octal or hexadecimal characters to represent xf6
echo "Hxf6me";//You need to check whether such text encoding is supported
--- ------------------Output results--------------------------------- ----------
H韇e
---------------------------------- ---------------------------------------------
1. Use printf() and sprintf( )Create formatted output
printf() outputs directly to the output buffer
The output of sprintf() is returned as a string
such as printf("Output content%.2fn",$PI());
All conversion specifications start with %
Data types include d-integer, s-string, f-floating point, b-binary
.2 is an optional width indicator, output to the right of the decimal point Pad with 0s
printf("%.2f",3.14159);
printf("%10.2f",3.14159);
printf("%.10f",3.14159);
printf( "%.9s",abcdefghijklmn);
printf("%5.2f,%f,%7.3fm",3.14159,3.14159,3.14159);
printf("%b %d %f %s n", 123,123,123,"test");
------------------------Output results----------------- -----------------------
3.14 3.143.1415900000abcdefghi 3.14,3.141590, 3.142m1111011 123 123.000000 test
-------- -------------------------------------------------- -----------
2. String padding
string str_pad(string input original string, int length the total length after adding [, string padding characters to be filled [, int pad_type ]Padding type])
The padding type is added to the left STR_PAD_LEFT, the default is added to the right, and padding is added to both ends STR_PAD_BOTH
$index = array("one"=>1,"two"=>155, "three"=>1679);
echo "
";
echo str_pad("This is the title",50," ",STR_PAD_BOTH)."n";
foreach($index as $inkey=>$inval)
echo str_pad($inkey,30,".").str_pad($inval,20,".",STR_PAD_LEFT)."n";
echo "
";
---------------------Output results--------------------- ------------------


This is the title
one............. ........................1
two............ ........................155
three............. ............1679


------------- -------------------------------------------------- -----
string strtolower(string subject)//Convert to lowercase
string strtoupper(string subject)//Convert to uppercase
string ucfirst(string subject)//Capitalize the first letter
string ucwords(string subject)//Capitalize the first letter of each word
string ltrim(string subject)//Remove the left blank
string rtrim(string subject)//Remove the right blank
string trim(string subject) ) to remove the left and right blanks, which include null, tab, line feed, carriage return and space
string n12br (string source) // Convert the newline character represented by n to
mark
3. characters String comparison
integer strcmp(sting str1,string str2) //str1 is greater than str2 and returns -1 str1 is less than str2 and returns 1 str1 and str2 are equal and returns 0
integer strmcmp(sting str1,string str2,integer length) // The third parameter limits comparison to length characters
print strcmp("aardvark","aardwolf");
print strncmp("aardvark","aardwolf",4);
----- ----------------Output results-------------------------------- --------
-10

---------------------------------- -------------------------------------
strcasecmp() and strncasecmp() are not Case-sensitive comparison function
4. Find and extract substrings
string substr(sting source,integer start[,integer length])//Take length characters from start
start and length can Use negative values
$var = "abcdefgh";
print substr($var,2);//Start counting from 0
print substr($var,2,3);
print substr ($var,-1);//Start from the end of the string
print substr($var,-5,2);
print substr($var,-5,-2);
---------------------Output results-------------------------- -------------
cdefgh
cde
h
de
def

---------- -------------------------------------------------- --------
integer strpos(string haystack,string needle[,integer offset])//Find the position of the substring and return the first occurrence.
integer strrpos(string haystack,string needle)//Only search for a single character (only take the first one for multiple characters), and return the index of the last occurrence.
There are also common functions for extracting the found part from a string
string strstr(string haystack, string needle)//Not case sensitive
string stristr(string haystack,string needle)//Case sensitive
string strrchr(string haystack,sting needle)
******* **** array explode(string separator,string subject[,integer limit])//Return a string array
array implode(string glue,array pieces)//Return a string
//// ////////////////////////code snippet/////////////////////////// ////////////////
$guest = "this is a string";
$guestArray = explode(" ",$guest);
var_dump($guestArray );
sort($guestArray);
echo implode(",",$guestArray);
////////////////////// //////////////////////////////////////////////////////
------------------------Output results------------------------ ----------------
array(4) { [0]=> string(4) "this" [1]=> string(2) "is" [2]=> string(1) "a" [3]=> string(6) "string" }a,is,string,this
------------------------------------------------ -----------------------------
5. Replacement characters and substrings
string substr_replace(string source,string replace ,int start[,int length])

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