- file
Either a path to a file, a connection, or literal data (either a
single string or a raw vector). file can also be a character vector
containing multiple filepaths or a list containing multiple connections.
Files ending in .gz, .bz2, .xz, or .zip will be automatically
uncompressed. Files starting with http://, https://, ftp://, or
ftps:// will be automatically downloaded. Remote gz files can also be
automatically downloaded and decompressed.
Literal data is most useful for examples and tests. To be recognised as
literal data, wrap the input with I().
- delim
One or more characters used to delimit fields within a
file. If NULL the delimiter is guessed from the set of c(",", "\t", " ", "|", ":", ";").
- col_names
Either TRUE, FALSE or a character vector
of column names.
If TRUE, the first row of the input will be used as the column
names, and will not be included in the data frame. If FALSE, column
names will be generated automatically: X1, X2, X3 etc.
If col_names is a character vector, the values will be used as the
names of the columns, and the first row of the input will be read into
the first row of the output data frame.
Missing (NA) column names will generate a warning, and be filled
in with dummy names ...1, ...2 etc. Duplicate column names
will generate a warning and be made unique, see name_repair to control
how this is done.
- col_types
One of NULL, a cols() specification, or
a string.
If NULL, all column types will be imputed from guess_max rows
on the input interspersed throughout the file. This is convenient (and
fast), but not robust. If the imputation fails, you'll need to increase
the guess_max or supply the correct types yourself.
Column specifications created by list() or cols() must contain
one column specification for each column. If you only want to read a
subset of the columns, use cols_only().
Alternatively, you can use a compact string representation where each
character represents one column:
c = character
i = integer
n = number
d = double
l = logical
f = factor
D = date
T = date time
t = time
? = guess
_ or - = skip
By default, reading a file without a column specification will print a
message showing what readr guessed they were. To remove this message,
set show_col_types = FALSE or set options(readr.show_col_types = FALSE).
- col_select
Columns to include in the results. You can use the same
mini-language as dplyr::select() to refer to the columns by name. Use
c() to use more than one selection expression. Although this
usage is less common, col_select also accepts a numeric column index. See
?tidyselect::language for full details on the
selection language.
- id
Either a string or 'NULL'. If a string, the output will contain a
variable with that name with the filename(s) as the value. If 'NULL', the
default, no variable will be created.
- skip
Number of lines to skip before reading data. If comment is
supplied any commented lines are ignored after skipping.
- n_max
Maximum number of lines to read.
- na
Character vector of strings to interpret as missing values. Set this
option to character() to indicate no missing values.
- 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 TRUE then blank rows will not be represented at all. If it is
FALSE then they will be represented by NA values in all the columns.
- 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 TRUE, the value '""' represents
a single quote, '"'.
- escape_backslash
Does the file use backslashes to escape special
characters? This is more general than escape_double as backslashes
can be used to escape the delimiter character, the quote character, or
to add special characters like \\n.
- locale
The locale controls defaults that vary from place to place.
The default locale is US-centric (like R), but you can use
locale() to create your own locale that controls things like
the default time zone, encoding, decimal mark, big mark, and day/month
names.
- guess_max
Maximum number of lines to use for guessing column types.
See vignette("column-types", package = "readr") for more details.
- altrep
Control which column types use Altrep representations,
either a character vector of types, TRUE or FALSE. See
vroom_altrep() for for full details.
- altrep_opts
lifecycle::badge("deprecated")
- 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 knitting a document. The automatic
progress bar can be disabled by setting option readr.show_progress to
FALSE.
- show_col_types
Control showing the column specifications. If TRUE
column specifications are always show, if FALSE they are never shown. If
NULL (the default) they are shown only if an explicit specification is not
given to col_types.
- .name_repair
Handling of column names. The default behaviour is to
ensure column names are "unique". Various repair strategies are
supported:
"minimal": No name repair or checks, beyond basic existence of names.
"unique" (default value): Make sure names are unique and not empty.
"check_unique": no name repair, but check they are unique.
"universal": Make the names unique and syntactic.
A function: apply custom name repair (e.g., name_repair = make.names
for names in the style of base R).
A purrr-style anonymous function, see rlang::as_function().
This argument is passed on as repair to vctrs::vec_as_names().
See there for more details on these terms and the strategies used
to enforce them.