Concatenation of the ascii_lowercase and ascii_uppercase constants.

Sequence of lowercase letters in the English alphabet.

Sequence of uppercase letters in the English alphabet.

Sequence of decimal digits from 0 to 9.

Sequence of hexadecimal digits from 0 to 9, a to f, and also A to F.

Sequence of octal digits from 0 to 7.

Sequence of ASCII characters which are considered printable: digits, ascii_letters, punctuation, and whitespace.

Sequence of ASCII characters which are considered punctuation: !"#$%&'()*+,-./:;<=>?@[\]^_{|}~`

Sequence of ASCII characters which are considered whitespace: space, tab, linefeed, return, formfeed, and vertical tab.