R Language Reading and writing tabular data in plain-text files (CSV, TSV, etc.) Importing fixed-width files
Example
Fixed-width files are text files in which columns are not separated by any character delimiter, like , or ;, but rather have a fixed character length (width). Data is usually padded with white spaces.
An example:
Column1 Column2 Column3 Column4Column5
1647 pi 'important' 3.141596.28318
1731 euler 'quite important' 2.718285.43656
1979 answer 'The Answer.' 42 42
Let's assume this data table exists in the local file constants.txt in the working directory.
Importing with base R
df <- read.fwf('constants.txt', widths = c(8,10,18,7,8), header = FALSE, skip = 1)
df
#> V1 V2 V3 V4 V5
#> 1 1647 pi 'important' 3.14159 6.28318
#> 2 1731 euler 'quite important' 2.71828 5.43656
#> 3 1979 answer 'The Answer.' 42 42.0000
Note:
- Column titles don't need to be separated by a character (
Column4Column5) - The
widthsparameter defines the width of each column - Non-separated headers are not readable with
read.fwf()
Importing with readr
library(readr)
df <- read_fwf('constants.txt',
fwf_cols(Year = 8, Name = 10, Importance = 18, Value = 7, Doubled = 8),
skip = 1)
df
#> # A tibble: 3 x 5
#> Year Name Importance Value Doubled
#> <int> <chr> <chr> <dbl> <dbl>
#> 1 1647 pi 'important' 3.14159 6.28318
#> 2 1731 euler 'quite important' 2.71828 5.43656
#> 3 1979 answer 'The Answer.' 42.00000 42.00000
Note:
- readr's
fwf_*helper functions offer alternative ways of specifying column lengths, including automatic guessing (fwf_empty) - readr is faster than base R
- Column titles cannot be automatically imported from data file
