How to convert a given substring into * in PHP (case sensitive)-PHP Problem-php.cn

In the previous article "How does PHP replace a substring of a certain length with a * sign" we introduced a method of string replacement. This time we introduce another method for string replacement and see how this method replaces a given substring with an * sign.

The method introduced above is to perform string replacement by giving the replacement start position and replacement length. This article introduces another method: directly give the substring that needs to be replaced for replacement. Because the replacement substring is directly set, there will be a case problem, which is divided into two situations: case sensitive and Case insensitivity. Today we will introduce the case-sensitive replacement method.

Let’s take a look at the following example:

"; echo str_replace($search2, $replace, $str)."
"; ?>

Copy after login

Observe the above code, we need to change the “hello” in the string$str" and "world" values are replaced with*; and$strin the string "hello,world,Hello,World" There are two types of replacement substrings, the only difference lies in the size of the first letter.

Because the str_replace() function is used to perform string replacement, this function is case-sensitive and case-sensitive, so it only searches for "in the string$str" hello" and "world" values, and replace them with*numbers respectively. So the output result is:

How to convert a given substring into * in PHP (case sensitive)

#Understand how to replace the given substring with an * sign in a case-sensitive manner. Let's take a look at the

function str_replace()that implements this function.

str_replace($search,$replace,$string,$count)The function can replace some characters in the string in a case-sensitive manner; the function accepts three required parameters$search(the substring to search for),$replace(the value to be replaced),$string(the string), and an optional parameter$ count(a variable).

Through the above example, we know the meaning of the first three required parameters. Let’s talk about the omitted parameters

$count.

The value of parameter

$countneeds to be set to a variable to count and return the number of times replacement is performed. To put it simply, by setting the parameter$count, you can know how many replacements have been performed in total.

Let’s take a look at the usage of parameter

$countthrough code examples.

"; echo "一共执行了 $i"." 次替换

"; echo str_replace($search2, $replace, $str,$i)."
"; echo "一共执行了 $i"." 次替换

"; echo str_replace($search3, $replace, $str,$i)."
"; echo "一共执行了 $i"." 次替换
"; ?>

Copy after login

Output result:

How to convert a given substring into * in PHP (case sensitive)

Okay, that’s all. If you want to know anything else, you can click this. → →

php video tutorial

Finally, I recommend reading a classic course "

PHP String Processing (Jade Girl Heart Sutra Edition)", it's free~ come and learn !

The above is the detailed content of How to convert a given substring into * in PHP (case sensitive). For more information, please follow other related articles on the PHP Chinese website!