Tidyverse selections implement a dialect of R where operators make it easy to select variables:
: for selecting a range of consecutive variables.
! for taking the complement of a set of variables.
& and | for selecting the intersection or the union of two sets of variables.
c() for combining selections.
In addition, you can use selection helpers such as:
everything() : Matches all variables.
last_col() : Select last variable, possibly with an offset.
These helpers select variables based on their names:
starts_with() : Starts with a prefix.
ends_with() : Ends with a suffix.
contains() : Contains a literal string.
matches() : Matches a regular expression.
num_range() : Matches a numerical range like x01, x02, x03.
These functions select variables from a character vector.
all_of() : Matches variable names in a character vector. All names must be present, otherwise an out-of-bounds error is thrown.
any_of() : Same as all_of(), except that no error is thrown for names that don’t exist.
select 使用变量作为参数的时候会警告,select(var_vector) 的正确写法应该是select(all_of(var_vector)) ,因为可能出现 var_vector 这个变量名本身是column name的情况。
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