ascii code table PHP detailed explanation of ASCII code comparison table and character conversion

1. General ASCII code comparison table

Illustrated ASCII code comparison table, taking the 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 0 to 9 Ten Arabic numerals;
(2) 65 to 90 are 26 uppercase English letters;
(3) 97 to 122 are 26 lowercase English letters;
(4) other punctuation marks, arithmetic symbols, etc.;
two, ASCII extension code comparison table

Three, PHP character conversion function description

For specific character conversion function description, please refer to [PHP function article detailed explanation of decimal, binary, octal and hexadecimal conversion functions ]
Convert decimal to binary decbin() function
Convert decimal to octal decoct() Function
Convert decimal to hexadecimal dechex() Function
Convert binary to hexadecimal bin2hex() Function
Convert binary to decimal bindec() function
Octal to decimal octdec() function
Hexadecimal to decimal hexdec() function
Any base conversion base_convert() function
Character conversion example
Example 1, how to convert a character to binary, octal or hexadecimal System, 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 The decimal value of the character : ord('a'); //Output 97
binary: decbin(ord('a')); //Output 1100001
octal: decoct(ord('a')); //Output 141
hexadecimal System: 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 the binary Is hexadecimal or decimal
Hex: bin2hex(decbin(ord('a'))); //Output 31313030303031
Binary J: bindec(decbin(ord('a'))); //Output 97
The ord() function discussed above will be discussed in detail in the next issue of the Chinese character encoding research series.
Fourth, reference materials
PHP functions detailed explanation of decimal, binary, octal and hexadecimal conversion functions
asciitable comparison chart
Wikipedia ASCII
Baidu Encyclopedia ASCII

The above introduces the ascii code table. PHP explains the ASCII code comparison table and character conversion in detail, including the content of the ascii code table. I hope it will be helpful to friends who are interested in PHP tutorials.