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This article mainly explains "how to compare strings in PHP". The content in the article is simple and clear, and it is easy to learn and understand. Please follow the editor's train of thought to study and learn "how to compare strings in PHP".

There are two functions in PHP to compare strings. They are the strcmp () and strcasecmp () functions. Let's introduce the usage of these two functions respectively.

Strcmp () function

In PHP, you can compare strings by comparing case through the strcmp () function. The basic syntax format of the strcmp () function is as follows:

Strcmp (string1,string2)

It should be noted that parameter string1 and parameter string2 are the two strings used to compare. If the returned result is equal to 0, it means that the two strings are equal. If the returned result is greater than 0, it means that the string string1 is greater than the string string2, and if the returned result is less than 0, the string string1 is less than the string string2.

Let's take a look at the application of the strcmp () function through a simple example, as follows:

Output result:

It should be noted that the strcmp () function is binary-safe and case-sensitive.

Next let's take a look at the use of the strcasecmp () function, which is very similar to the strcmp () function.

Strcasecmp () function

The strcmp () function above is most commonly used to compare case, and the function is case-sensitive, but the strcasecmp () function is different in that it is not case-sensitive, which is the only difference between them.

The basic syntax format of the strcasecmp () function is as follows:

Strcasecmp (string1,string2)

It should be noted that parameter string1 and parameter string2 are the two strings used to compare. If the returned result is equal to 0, it means that the two strings are equal. If the returned result is greater than 0, it means that the string string1 is greater than the string string2, and if the returned result is less than 0, the string string1 is less than the string string2.

Let's take a look at how the output will be different from the example mentioned above, as follows:

Output result:

As you can see from the above example, the strcasecmp () function is not case-sensitive to compare strings.

Having introduced two more commonly used string comparison functions above, let's take a look at the strncmp () function as an additional knowledge.

Strncmp () function

The strncmp () function in PHP can compare strings as well as the strcasecmp () function and strcmp () function above. What's the difference between them? After looking at the syntax format of the strncmp () function, the basic syntax format of the strncmp () function is as follows:

Strncmp (string1,string2,length)

It is important to note that the parameters string1 and string2 are two strings used to compare like the two functions above, except that the latter parameter length. The parameter length is used to specify the number of characters each string is used to represent, that is, all strings are not compared by setting the parameter length.

If the returned result is equal to 0, it means that the two strings are equal. If the returned result is greater than 0, the string string1 is greater than the string string2. If the returned result is less than 0, the string string1 is less than the string string2.

Next, let's take a look at the use of the strncmp () function through an example, as follows:

Output result:

Therefore, we compare the specified characters through the strncmp () function, which is also case-sensitive.

Thank you for reading, the above is the content of "how to compare strings in PHP". After the study of this article, I believe you have a deeper understanding of how to compare strings in PHP, and the specific use needs to be verified in practice. Here is, the editor will push for you more related knowledge points of the article, welcome to follow!

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