php之str_replace详解_PHP教程
- WBOY原創
- 2016-07-13 10:22:52923瀏覽
php之str_replace详解
str_replace
(PHP 4, PHP 5)
str_replace — Replace all occurrences of the search string with the replacement string
Description
mixed str_replace ( mixed$search , mixed $replace , mixed $subject [, int &$count ]
)
This function returns a string or an array with all occurrences of search in subject replaced
with the givenreplace value.
If you don't need fancy replacing rules (like regular expressions), you should always use this function instead ofpreg_replace().
Parameters
If search and replace are
arrays, then str_replace() takes a value from each array and uses them to search and replace on subject.
If replace has fewer values than search,
then an empty string is used for the rest of replacement values. If search is
an array and replace is a string, then this replacement string is
used for every value of search. The converse would not make sense,
though.
If search or replace are
arrays, their elements are processed first to last.
search-
The value being searched for, otherwise known as the needle. An array may be used to designate multiple needles.
replace-
The replacement value that replaces found
searchvalues. An array may be used to designate multiple replacements. subject-
The string or array being searched and replaced on, otherwise known as the haystack.
If
subjectis an array, then the search and replace is performed with every entry ofsubject, and the return value is an array as well. count-
If passed, this will be set to the number of replacements performed.
Return Values
This function returns a string or an array with the replaced values.
Changelog
Version Description 5.0.0 The countparameter was added.4.3.3 The behaviour of this function changed. In older versions a bug existed when using arrays as both searchandreplaceparameters which caused emptysearchindexes to be skipped without advancing the internal pointer on thereplacearray. This has been corrected in PHP 4.3.3, any scripts which relied on this bug should remove empty search values prior to calling this function in order to mimic the original behavior.4.0.5 Most parameters can now be an array. Examples
Example #1 Basic str_replace() examples
<?php <br> // Provides: <br> $bodytag = str_replace("%body%", "black", "");<br> <br> // Provides: Hll Wrld f PHP<br> $vowels = array("a", "e", "i", "o", "u", "A", "E", "I", "O", "U");<br> $onlyconsonants = str_replace($vowels, "", "Hello World of PHP");<br> <br> // Provides: You should eat pizza, beer, and ice cream every day<br> $phrase = "You should eat fruits, vegetables, and fiber every day.";<br> $healthy = array("fruits", "vegetables", "fiber");<br> $yummy = array("pizza", "beer", "ice cream");<br> <br> $newphrase = str_replace($healthy, $yummy, $phrase);<br> <br> // Provides: 2<br> $str = str_replace("ll", "", "good golly miss molly!", $count);<br> echo $count;<br> ?>Example #2 Examples of potential str_replace() gotchas
<?php <br> // Order of replacement<br> $str = "Line 1\nLine 2\rLine 3\r\nLine 4\n";<br> $order = array("\r\n", "\n", "\r");<br> $replace = '<br>';<br> <br> // Processes \r\n's first so they aren't converted twice.<br> $newstr = str_replace($order, $replace, $str);<br> <br> // Outputs F because A is replaced with B, then B is replaced with C, and so on...<br> // Finally E is replaced with F, because of left to right replacements.<br> $search = array('A', 'B', 'C', 'D', 'E');<br> $replace = array('B', 'C', 'D', 'E', 'F');<br> $subject = 'A';<br> echo str_replace($search, $replace, $subject);<br> <br> // Outputs: apearpearle pear<br> // For the same reason mentioned above<br> $letters = array('a', 'p');<br> $fruit = array('apple', 'pear');<br> $text = 'a p';<br> $output = str_replace($letters, $fruit, $text);<br> echo $output;<br> ?>Notes
Note: This function is binary-safe.