PHPctype function application and summary

I turned to the php document today and accidentally saw the ctype function. I thought it was very useful. I recorded it for later use: ctype_alnum -- checkforalphanumericcharacter (s) to check whether it is only

Today, I flipped through the php document and accidentally saw the ctype function. I thought it was very useful. I recorded it for future use:

Ctype_alnum -- check for alphanumeric character (s)

Check if it only contains [A-Za-z0-9]

Ctype_alpha -- check for alphabetic character (s)

Check whether it only contains [a-za-z]

Ctype_cntrl -- check for control character (s)

Check whether it only contains character control characters such as "nrt ".

Ctype_digit -- check for numeric character (s)

Check that the string contains only numbers (0-9)

Ctype_graph -- check for any printable character (s) character t space

Check whether the string contains only printable characters (except spaces)

Ctype_lower -- check for lowercase character (s)

Check whether all characters are English letters and lowercase letters.

Ctype_print -- check for printable character (s)

Check whether the string contains only printable characters.

Ctype_punct -- check for any printable character which is not whitespace or an alphanumeric character

Check whether only printable characters including non-numbers, characters, and spaces are allowed.

Ctype_space -- check for whitespace character (s)

Check whether it only contains characters and spaces such "".

Ctype_upper -- check for uppercase character (s)

Check whether all characters are English letters and uppercase letters

Ctype_xdigit -- check for character (s) representing a hexadecimal digit

Check whether the string is a hexadecimal string and can only contain "0123456789abcdef"

Ctype function

Table of contents

Ctype_alnum-check for alphanumeric character (s) check string contains only numbers or letters, equivalent to regular [A-Za-z0-9]. there is a return value.

The ctype_alpha-check for alphabetic character (s) check string contains only letters. Return value.

Ctype_cntrl-check for control character (s) checks whether the string contains only control characters such as "'n' R'' t. Return value

Ctype_digit-check for numeric character (s) checks whether the string contains only numbers. Return value.

Ctype_graph-check for any printable character (s) character t space checks whether the string contains only the characters that can be output. Return value.

Ctype_lower-check for lowercase character (s) check whether the string contains only lowercase English letters. Return value.

Ctype_print-check for printable character (s) checks whether the string contains only printable characters. Return value.

Ctype_punct-check for any printable character which is not whitespace or an alphanumeric character checks whether the string contains only printable characters, and such characters cannot be non-spaces, numbers, or characters. Return value.

Ctype_space-check for whitespace character (s) check whether the string contains only spaces or "". return values

Ctype_upper-check for uppercase character (s) check whether the string contains only uppercase English letters. Return value.

Ctype_xdigit-check for character (s) representing a hexadecimal digit checks whether the string is a hexadecimal string.