isdigitint

isdigitint is a programming utility or predicate used to determine whether a given input represents an integer value composed exclusively of decimal digits. It is not a standardized function across languages, and its exact behavior can vary by library or implementation. In many contexts it operates on strings, returning true when the string encodes a whole number with no extra characters.

Definition and variants: The most common variant accepts strings containing only digits 0 through 9, optionally prefixed by a plus or minus sign. A stricter variant requires digits only, with no sign. Whitespace, thousands separators, or locale-specific digit forms are typically disallowed. Some implementations also accept numeric types directly, returning true if the value is an integer.

Implementation notes: A typical approach is to convert the input to a string, trim whitespace, and verify the characters are digits. A regular expression such as ^[+-]?\d+$ (for the sign-allowing variant) or ^\d+$ (for the strict variant) is commonly used. It is important to distinguish syntactic validity from numeric range; passing the isdigitint test does not guarantee the value fits within a language’s integer type or its bounds.

Relation to other concepts:isdigitint differs from isInteger, which tests numeric type rather than textual representation, and from isNumeric, which may allow decimal points or exponents. Some languages provide built-in predicates with similar purposes; others require custom implementations or libraries.

Usage and caveats: isdigitint is commonly used for input validation and parsing pipelines. When applying it, consider how leading or trailing whitespace is handled, whether signs are allowed, and whether the input might include locale-specific digits or separators. Documentation should clarify the exact allowed forms and any range considerations.