Fread specific rows based on column matches — read

Deprecated. Do not use

Usage

read_colmatch(
  file,
  col,
  sep = NULL,
  values_to_match,
  drop = NULL,
  schema_detect_nrow = 1000,
  col_classes = NULL,
  verbose = FALSE,
  ...
)

fread_colmatch(...)

Arguments

file: path to file to load
col: name of col to match from
sep: grep term to match as column delimiters within the file
values_to_match: values in col to match given as a vector
drop: Vector of column names or numbers to drop, keep the rest.
schema_detect_nrow: numeric. how many rows to sample to guess the arrow schema to use.
col_classes: character vector (optional). R types each column is expected to be. These will be translated to arrow schema. Only necessary if the schema autodetection from schema_detect_nrow is insufficient. Select one or multiple of "integer", "double", "raw", "character", "logical", "Date", "POSIXct"
verbose: be verbose
...: additional parameters to pass to arrow::open_delim_dataset()

Value

A tibble

Functions

fread_colmatch(): deprecated.

Examples

f <- file.path(tempdir(), "my_file.csv")
x <- data.frame(a = c("a", "b", "c"), b = 1:3, c = 5:7)
write.csv(x, f)
read_colmatch(f, col = "a", values_to_match = c("a", "c"))
#> Error: package 'dplyr' is not yet installed
#> 
#>  To install:
#> install.packages(c("dplyr"))
read_colmatch(f, col = "a", values_to_match = c("a", "c"), drop = c(1, 4))
#> Error: package 'dplyr' is not yet installed
#> 
#>  To install:
#> install.packages(c("dplyr"))
read_colmatch(f, 
    col = "a", values_to_match = c("a", "c"), drop = c("V1", "b")
)
#> Error: package 'dplyr' is not yet installed
#> 
#>  To install:
#> install.packages(c("dplyr"))
unlink(f)