PHP Returns a function addcslashes () that refers to the character before the backslash

Source: Internet
Author: User


Add a backslash before the character "W":

<?php $str = addcslashes ("Hello world!", "W"); Echo ($STR);?>

Definition and usage

The Addcslashes () function returns a string that adds a backslash before the specified character.

Note: the Addcslashes () function is case-sensitive.

Note: Be careful when applying addcslashes () to 0 (NULL), R (carriage return), N (newline), T (page break), F (tab), and V (Vertical tab). In PHP, the \ r, \ n, \ t, \f, and \v are predefined escape sequences.


Addcslashes (String,characters)
parameters description
string required. Specifies the string to be escaped
characters required. Specifies the character or range of characters to be escaped.

Technical details

return value: Returns the escaped string.
PHP version: 4 +

More examples

To add a backslash to a specific character in a string:

<?php$str = "Welcome to my humble homepage!"; echo $str. " <br> "; Echo addcslashes ($str, ' m ')." <br> "; Echo addcslashes ($str, ' H ')." <br> ";? >

To add a backslash to a character in a range in a string:

<?php$str = "Welcome to my humble homepage!"; echo $str. " <br> "; Echo addcslashes ($str, ' A. Z '). " <br> "; Echo addcslashes ($str, ' A. Z '). " <br> "; Echo addcslashes ($str, ' A. G ');? >

The following is a brief introduction to the use of these two functions:

String Addcslashes (String str,string charlist)

1th parameter str is the original string to be lost

The 2nd parameter, charlist, shows which characters in the original string need to be preceded by a character "\".

String stripcslashes (String str)

Remove the "\" from the string.

In addition, the Addslashes function can also be used to escape directly for "'".

Examples are as follows:

<?php$sql = "Update book set Bookname= ' Let ' s go ' where bookid=1"; echo $sql. " <br/> "; $new _sql = addcslashes ($sql, "'"); echo $new _sql. " <br/> "; $new _sql_01 = stripcslashes ($new _sql); echo $new _sql_01. " <br/> "; echo addslashes ($sql);? >

The results of the operation are as follows:

Update book set Bookname= ' Let's Go ' where Bookid=1update book set bookname=\ ' let\ ' s go\ ' where bookid=1update book set Boo Kname= ' Let's Go ' where Bookid=1update book set bookname=\ ' let\ ' s go\ ' where bookid=1

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