Assertions to Check Properties of Strings

A set of predicates and assertions for checking the properties of strings. This is mainly for use by other package developers who want to include run-time testing features in their own packages. End-users will usually want to use assertive directly.

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A set of predicates and assertions for checking the properties of strings. Most of the documentation is on the assertive page. End-users will usually want to use assertive directly.


To install the stable version, type:


To install the development version, you first need the devtools package.


Then you can install the assertive.strings package using



is_empty_character, is_non_empty_character, is_missing_or_empty_character, and is_non_missing_nor_empty_character check for empty and missing (or not) character vectors.

is_an_empty_string, is_a_non_empty_string, is_a_missing_or_empty_string, and is_a_non_missing_nor_empty_string do the same, for single strings.

is_numeric_string checks for strings that contain numbers.

is_single_character checks for single characters.

is_matching_fixed, is_matching_regex, is_not_matching_fixed, and is_not_matching_regex all check whether a string matches a pattern or not.


Predicates that return a vector have two corresponding assertions. For example, is_numeric_string has assert_all_are_numeric_strings and assert_any_are_numeric_strings.

Predicates returning a single logical value have one corresponding assertion. For example, is_an_empty_string has assert_is_an_empty_string.


character_to_list_of_integer_vectors converts a character vector of numbers to a list of integer vectors.


0.0-3 Added is_matching_* predicates + assertions. (Thanks Aditya!) 0.0-2 Added is_logical_string + assertions. Reexported some deprecated fns for back compatibility. Dropped devtools dependency. 0.0-1 Content extracted from assertive 0.3-0, and tidied.

Reference manual

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0.0-3 by Richard Cotton, 5 years ago

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Browse source code at

Authors: Richard Cotton [aut, cre] , Aditya Bhagwat [ctb]

Documentation:   PDF Manual  

GPL (>= 3) license

Imports assertive.base, assertive.types, stringi

Suggests testthat

Imported by assertive,,,, poio.

See at CRAN