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Regular expression patterns for numbers

number_patterns.Rd

Regular expression patterns for numbers

Usage

number_patterns

Details

natural

positive integers without a sign

nonnegative_integer_no_sign

only digits

integer

an optional +- at the beginning followed by only digits (note that "-0" is valid)

float_no_sign

digits, a decimal point, and more digits

float_or_integer_relaxed

an optional +- followed by one of the following:

  • digits

  • digits then a decimal point

  • a decimal point then digits

  • digits then a decimal point then digits

float_or_integer_strict

an optional +- followed by digits optionally followed by a decimal point and digits (starting or ending with a decimal point is not allowed).

scientific_notation

Strict scientific notation made of the following, in order:

  • an optional +-

  • a coefficient that is zero (with an optional decimal point and optional additional zeros), a natural number, or a float that does not start with zero

  • one of "e", "E", "d", or "D"

  • a optional +-

  • integer

scientific_notation_relaxed

Relaxed scientific notation (relaxing on the coefficient rules) made of the following, in order:

  • float_or_integer_relaxed

  • one of "e", "E", "d", or "D"

  • a optional +-

  • integer

number_relaxed

Any number format above (based on scientific_notation_relaxed with the exponent as an optional component)

Examples

grepl(pattern=number_patterns$scientific_notation_relaxed, "1e5")
#> [1] TRUE
grepl(pattern=number_patterns$scientific_notation_relaxed, "1e-5")
#> [1] TRUE
grepl(pattern=number_patterns$scientific_notation_relaxed, "1e.5")
#> [1] FALSE