


During this time, I was reading the book "PHP and MySQL Web Development" and saw the explanation of str_replace. A small tip was written: You can use arrays to pass in all three of str_replace, but the explanation is relatively simple, so I decided to test this function myself. The execution result when each parameter is passed into the array.
Function prototype: mixed str_replace(mixed needle, mixed new_needle, mixed haystack[,int &count]);
needle: the string to be replaced, new_needle: the string used for replacement, haystack: the operation string, count: the number of replacements [Optional parameters]
We focus on testing the first three execution methods when using arrays:
When no array is used, this function directly uses new_needle to replace all needles and returns the replaced string. For example: str_replace("m","n","my name is jim!") returns ny nane is jin!
1. Only use arrays for needles.
Example: str_replace(array('m','i'),'n',"my name is jim!"); Return: ny nane ns jnn!
It can be seen that the function sequentially pairs each element in the array Replace the string and return the replaced string.
2. Only use arrays for new_needle.
Example: str_replace('m',array('n','z'),"my name is jim!n") returns: Arrayy naArraye is jiArray!
This replacement is more interesting, if it is used only for the second parameter Array, the function uses it as a string Array, replacing all needles with arrays.
3. Only use arrays for haystack.
Example: str_replace("m","n",array("my name is jim!","the game is over!")) The execution result of this statement returns an array, which is the two strings passed in. The result after replacement.
If you output the array content, you will see: ny nane is jin! the gane is over!
4. Use arrays for both needle and new_needle.
Example: str_replace(array("m","i"),array("n","z"),"my name is jim!") returns: ny nane zs jzn!
View the execution results and you can see that if If the first two parameters use arrays, the function replaces the strings of each object item in the array, and replaces the first item of needle with the first item of new_needle. And so on.
If the needle array is longer than new_deedle, for example: str_replace(array("m","i","s"),array("n","z"),"my name is jim!"); return: ny nane z jzn! It can be seen that the extra strings in the needle array are replaced with empty strings.
If the new_needle array is longer than needle, for example: str_replace(array("m","i"),array("n","z","x"),"my name is jim!") returns ny nane zs jzn! It can be seen that the redundant items of new_needle are ignored.
5. All three parameters use arrays.
For example: array content returned by str_replace(array("m","i"),array("n","z"),array("my name is jim!","the game is over")): ny nane zs jzn!the gane zs over
This is easier to understand. Replace the two strings separately.
A brief summary to prevent yourself from forgetting!
The above has introduced the replace function. A summary of the use of str_replace function in PHP, including the content of the replace function. I hope it will be helpful to friends who are interested in PHP tutorials.

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