| vroom | R Documentation |
Read a delimited file into a tibble
vroom(
file,
delim = NULL,
col_names = TRUE,
col_types = NULL,
col_select = NULL,
id = NULL,
skip = 0,
n_max = Inf,
na = c("", "NA"),
quote = "\"",
comment = "",
skip_empty_rows = TRUE,
trim_ws = TRUE,
escape_double = TRUE,
escape_backslash = FALSE,
locale = default_locale(),
guess_max = 100,
altrep = TRUE,
num_threads = vroom_threads(),
progress = vroom_progress(),
show_col_types = NULL,
.name_repair = "unique"
)
file |
Either a path to a file, a connection, or literal data (either a
single string or a raw vector). Files ending in Literal data is most useful for examples and tests. To be recognised as
literal data, wrap the input with |
delim |
One or more characters used to delimit fields within a
file. If |
col_names |
Either If If Missing ( |
col_types |
One of If Column specifications created by Alternatively, you can use a compact string representation where each character represents one column:
By default, reading a file without a column specification will print a
message showing the guessed types. To suppress this message, set
|
col_select |
Columns to include in the results. You can use the same
mini-language as |
id |
Either a string or 'NULL'. If a string, the output will contain a column with that name with the filename(s) as the value, i.e. this column effectively tells you the source of each row. If 'NULL' (the default), no such column will be created. |
skip |
Number of lines to skip before reading data. If |
n_max |
Maximum number of lines to read. |
na |
Character vector of strings to interpret as missing values. Set this
option to |
quote |
Single character used to quote strings. |
comment |
A string used to identify comments. Any text after the comment characters will be silently ignored. |
skip_empty_rows |
Should blank rows be ignored altogether? i.e. If this
option is |
trim_ws |
Should leading and trailing whitespace (ASCII spaces and tabs) be trimmed from each field before parsing it? |
escape_double |
Does the file escape quotes by doubling them?
i.e. If this option is |
escape_backslash |
Does the file use backslashes to escape special
characters? This is more general than |
locale |
The locale controls defaults that vary from place to place.
The default locale is US-centric (like R), but you can use
|
guess_max |
Maximum number of lines to use for guessing column types.
See |
altrep |
Control which column types use Altrep representations,
either a character vector of types, |
num_threads |
Number of threads to use when reading and materializing vectors. If your data contains newlines within fields the parser will automatically be forced to use a single thread only. |
progress |
Display a progress bar? By default it will only display
in an interactive session and not while executing in an RStudio notebook
chunk. The display of the progress bar can be disabled by setting the
environment variable |
show_col_types |
Control showing the column specifications. If |
.name_repair |
Handling of column names. The default behaviour is to
ensure column names are
This argument is passed on as |
# get path to example file
input_file <- vroom_example("mtcars.csv")
input_file
# Read from a path
# Input sources -------------------------------------------------------------
# Read from a path
vroom(input_file)
# You can also use paths directly
# vroom("mtcars.csv")
## Not run:
# Including remote paths
vroom("https://github.com/tidyverse/vroom/raw/main/inst/extdata/mtcars.csv")
## End(Not run)
# Or directly from a string with `I()`
vroom(I("x,y\n1,2\n3,4\n"))
# Column selection ----------------------------------------------------------
# Pass column names or indexes directly to select them
vroom(input_file, col_select = c(model, cyl, gear))
vroom(input_file, col_select = c(1, 3, 11))
# Or use the selection helpers
vroom(input_file, col_select = starts_with("d"))
# You can also rename specific columns
vroom(input_file, col_select = c(car = model, everything()))
# Column types --------------------------------------------------------------
# By default, vroom guesses the columns types, looking at 1000 rows
# throughout the dataset.
# You can specify them explicitly with a compact specification:
vroom(I("x,y\n1,2\n3,4\n"), col_types = "dc")
# Or with a list of column types:
vroom(I("x,y\n1,2\n3,4\n"), col_types = list(col_double(), col_character()))
# File types ----------------------------------------------------------------
# csv
vroom(I("a,b\n1.0,2.0\n"), delim = ",")
# tsv
vroom(I("a\tb\n1.0\t2.0\n"))
# Other delimiters
vroom(I("a|b\n1.0|2.0\n"), delim = "|")
# Read datasets across multiple files ---------------------------------------
mtcars_by_cyl <- vroom_example(vroom_examples("mtcars-[468]"))
mtcars_by_cyl
# Pass the filenames directly to vroom, they are efficiently combined
vroom(mtcars_by_cyl)
# If you need to extract data from the filenames, use `id` to request a
# column that reveals the underlying file path
dat <- vroom(mtcars_by_cyl, id = "source")
dat$source <- basename(dat$source)
dat
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