select-helpers: Versions of dplyr's select helpers that fail safely

In LearningToTalk/L2TDatabase: Helper Functions for the Learning-To-Talk 'MySQL' Database

Description

When dplyr's column-selection functions starts_with or matches fail to find a column, no columns are returned. These alternative versions return all available columns when no match is found. The result is that select(df, V1, maybe_starts_with("V2") still returns V1 even if there is no V2.

Usage

maybe_starts_with(...)

maybe_matches(...)

Arguments

...	arguments passed on to the dplyr select helpers

Value

the column indices for matching columns if any are found; otherwise, an empty numeric vector.

LearningToTalk/L2TDatabase documentation built on June 24, 2020, 3:45 a.m.