Let's talk about the difference between line feed and carriage return in php

A very common problem in PHP is how to wrap lines and carriage returns. Although in many cases, "carriage return" and "line feed" look the same, their actual meanings are different. In PHP, the difference between line feed and carriage return is very important. They not only affect the readability of the code, but may also cause some program errors. Next, let's take a look at the detailed difference between "carriage return" and "line feed" in PHP.

What is carriage return?

The ASCII code of the carriage return character is 13, and its English name is Carriage Return. Its function is to position the cursor to the beginning of the current line.

In different operating systems, the carriage return expression is different. For example, in Windows operating systems, a carriage return usually consists of two characters, the carriage return (CR) and the line feed (LF), \r\n. In UNIX operating systems, a carriage return usually consists of only a newline character, namely \n. On Mac operating systems, usually just the carriage return \r is used.

In PHP, we can use the special character \r to represent the carriage return character. For example:

echo "Hello\rWorld"

The output result of the above code is: World. This is because \r moves the cursor to the beginning of the current line, overwriting the original Hello.

What is line break?

The ASCII code of the newline character is 10, and its English name is Line Feed. Its function is to move the cursor to the beginning of the next line.

In different operating systems, line breaks are expressed in different ways. For example, in the Windows operating system, a newline usually consists of a carriage return (CR) and a line feed (LF), that is, \r\n. In a UNIX operating system, a newline usually consists of a single newline character, that is, \n .

In PHP, we can use the special character \n to represent a newline character. For example:

echo "Hello\nWorld"

The output of the above code is:

Hello
World

Because \n functions as a newline , so when outputting, the cursor will move to the next line.

Combination of carriage return and line feed

In actual programming, carriage return and line feed are usually used in combination. For example, in Windows operating systems, line breaks require a combination of carriage return and line feed characters. That is\r\n, for example:

echo "Hello\r\nWorld"

The output result of the above code is:

Hello
World

This is because \r means carriage return, moving the cursor to the beginning of the current line, and then \n means line feed, moving the cursor to the beginning of the next line.

Summary

Although "carriage return" and "line feed" in PHP look similar, their functions are completely different. Enter moves the cursor to the beginning of the current line, and line feed moves the cursor to the beginning of the next line. In actual programming, we usually use them in combination, especially in Windows operating systems, where a combination of carriage return and line feed is needed to wrap the line. It should be noted that carriage returns and line feeds may be represented differently in different operating systems.

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