Detailed explanation of php ASCII code comparison table and character conversion

ASCII (American Standard Code for Information Interchange, American Standard Code for Information Interchange) is a computer coding system based on the Latin alphabet, mainly used to display modern English and other Western European languages. It is the most common single-byte encoding system today and is equivalent to the international standard ISO/IEC 646.

1. General ASCII code comparison table

Illustrated ASCII code comparison table , taking character A as an example
Dec represents decimal, such as 65
Hx represents hexadecimal, such as 41
Oct represents octal, such as 101
Char represents display characters, such as A

ASCII code comparison chart is divided into two units
1, control characters 0-31 and 127
2, displayable characters 32-126
(1) 48 ~57 is the ten Arabic numerals from 0 to 9;
(2) 65~90 is 26 uppercase English letters;
(3) 97~122 is 26 lowercase English letters;
(4) OthersPunctuation marks, operators, etc.;

2, ASCII extension code comparison table

3. PHP character conversion Function Description

For specific character conversion function description, please refer to [ PHP functionDetailed explanation of decimal, binary, octal and hexadecimal Decimal conversionFunction description]
Decimal to binary decbin() function
Decimal to octal decoct() function
Convert decimal to hexadecimal dechex() function
Convert binary to hexadecimal bin2hex() Function
Convert binary to decimal to binary bindec() Function
Convert octal to decimal octdec() function
Hexadecimal to decimal hexdec() function
Any base_convert() function

Character conversion example
Example 1, how to convert a character to binary, octal or hexadecimal, you can use the ord() function to first convert the character into an ASCII value, and then use the corresponding base conversion function to convert , as follows
a This character is converted to its binary/octal/hexadecimal system, as follows
a character's decimal: ord('a'); //Output 97
Binary: decbin(ord(' a')); //Output 1100001
octal: decoct(ord('a')); //Output 141
hexadecimal: dechex(ord('a')); //Output 61

Then you can check the output results of each decimal system against the ASCII code comparison table above.

Example 2, how to convert a binary to hexadecimal or decimal, such as the binary of a, as follows
Use the method of Example 1 to obtain the binary of the character a
decbin(ord('a'));
Then convert binary to hexadecimal or decimal
Hexadecimal: bin2hex(decbin(ord('a')));//Output 31313030303031
Binary J:bindec(decbin(ord('a'))); //Output 97

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