How to convert ascii code to string in php

In PHP development, sometimes it is necessary to convert ASCII codes into strings. This article will introduce how to convert ASCII code into a string in PHP.

1. What is ASCII code

ASCII code is a coding method inside the computer, which corresponds to a number for each letter, number and symbol. This number is its encoded value in the ASCII code table. ASCII codes are usually represented by 7-bit binary numbers, totaling 128 characters.

2. Method 1 of converting ASCII code to string: chr() function

In PHP, you can use the chr() function to convert ASCII code into string. The syntax of the chr() function is as follows:

chr(ascii)

where, ascii represents the ASCII code value that needs to be converted.

For example, to convert a character with an ASCII code value of 65 into a string, the code is as follows:

echo chr(65); // 输出 A

3. Method 2 of converting ASCII code to a string: directly output

In PHP, you can also directly use output functions such as echo and print to convert ASCII codes into strings. Because in PHP, strings are defined with double quotes or single quotes, and characters in double quotes or single quotes can be output directly, so the ASCII code value can also be output directly. For example, to convert a character with an ASCII code value of 65 into a string, the code is as follows:

echo "A"; // 输出 A

IV. Application example of ASCII code to string conversion

In actual development, ASCII code to character conversion Strings are often used in the following application scenarios:

1. Output special symbols

In some scenarios, it may be necessary to output some special symbols, such as copyright symbols (©) and trademark symbols (®) etc. These symbols have corresponding encoding values ​​in the ASCII code table, so they can be output by converting ASCII codes to strings.

For example, the output copyright symbol (©) code is as follows:

echo chr(169); // 输出 ©

2. String encryption

In some scenarios with higher security, it may The string needs to be encrypted. One method is to convert the string into an ASCII code value for calculation and processing.

For example, convert the string "hello" into an ASCII code value and encrypt it. The code is as follows:

$str = "hello";
$ascii_str = "";
for ($i = 0; $i < strlen($str); $i++) {
    $ascii_str .= ord($str[$i])." ";
}
echo "ASCII 码为：".$ascii_str; // 输出 ASCII 码为：104 101 108 108 111

The above code uses a loop to traverse each character in the string and use ord() The function converts characters into ASCII code values ​​and stores the result in the $ascii_str variable.

5. Summary

This article introduces how to convert ASCII code into a string in PHP. In actual development, converting ASCII codes into strings is usually used in scenarios such as outputting special symbols and string encryption.

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