ASCIIletters

ASCIIletters refers to the set of Latin letters A through Z and a through z encoded in the ASCII character set. These 52 characters are widely used in programming, identifiers, text processing, and data interchange, particularly in English-language contexts.

Encoding details: ASCII uses 7-bit codes. Uppercase letters A–Z occupy decimal values 65 to 90 (0x41 to 0x5A); lowercase letters a–z occupy 97 to 122 (0x61 to 0x7A).

Properties and limitations: ASCIIletters are portable across systems that support ASCII; they do not cover letters with diacritics or non-Latin scripts. In modern systems, ASCII is a subset of Unicode, occupying the first 128 code points. Many programming languages restrict identifiers to ASCII letters (often along with digits and the underscore), though some languages allow extended Unicode letters in identifiers.

History and usage: ASCII was defined in the 1960s and became a widely adopted standard for text in computing. It underpins legacy encodings and remains foundational in software development, data formats, and networking.

Related concepts include the Latin alphabet, Unicode and its UTF-8 encoding, and ISO/IEC 646 variants that extend ASCII's character set while preserving compatibility for letters A–Z.