R readr parse_atomic 解析逻辑数、整数和实数

parse_logical(x, na = c("", "NA"), locale = default_locale(), trim_ws = TRUE)

parse_integer(x, na = c("", "NA"), locale = default_locale(), trim_ws = TRUE)

parse_double(x, na = c("", "NA"), locale = default_locale(), trim_ws = TRUE)

parse_character(x, na = c("", "NA"), locale = default_locale(), trim_ws = TRUE)

col_logical()

col_integer()

col_double()

col_character()

其他解析器：col_skip() , cols_condense() , cols() , parse_datetime() , parse_factor() , parse_guess() , parse_number() , parse_vector()

parse_integer(c("1", "2", "3"))
#> [1] 1 2 3
parse_double(c("1", "2", "3.123"))
#> [1] 1.000 2.000 3.123
parse_number("$1,123,456.00")
#> [1] 1123456

# Use locale to override default decimal and grouping marks
es_MX <- locale("es", decimal_mark = ",")
parse_number("$1.123.456,00", locale = es_MX)
#> [1] 1123456

# Invalid values are replaced with missing values with a warning.
x <- c("1", "2", "3", "-")
parse_double(x)
#> Warning: 1 parsing failure.
#> row col expected actual
#>   4  -- a double      -
#> [1]  1  2  3 NA
#> attr(,"problems")
#> # A tibble: 1 × 4
#>     row   col expected actual
#>   <int> <int> <chr>    <chr> 
#> 1     4    NA a double -     
# Or flag values as missing
parse_double(x, na = "-")
#> [1]  1  2  3 NA