read_delim_chunked {readr} | R Documentation |
Read a delimited file by chunks
read_delim_chunked( file, callback, delim = NULL, chunk_size = 10000, quote = "\"", escape_backslash = FALSE, escape_double = TRUE, col_names = TRUE, col_types = NULL, locale = default_locale(), na = c("", "NA"), quoted_na = TRUE, comment = "", trim_ws = FALSE, skip = 0, guess_max = chunk_size, progress = show_progress(), show_col_types = should_show_types(), skip_empty_rows = TRUE ) read_csv_chunked( file, callback, chunk_size = 10000, col_names = TRUE, col_types = NULL, locale = default_locale(), na = c("", "NA"), quoted_na = TRUE, quote = "\"", comment = "", trim_ws = TRUE, skip = 0, guess_max = chunk_size, progress = show_progress(), show_col_types = should_show_types(), skip_empty_rows = TRUE ) read_csv2_chunked( file, callback, chunk_size = 10000, col_names = TRUE, col_types = NULL, locale = default_locale(), na = c("", "NA"), quoted_na = TRUE, quote = "\"", comment = "", trim_ws = TRUE, skip = 0, guess_max = chunk_size, progress = show_progress(), show_col_types = should_show_types(), skip_empty_rows = TRUE ) read_tsv_chunked( file, callback, chunk_size = 10000, col_names = TRUE, col_types = NULL, locale = default_locale(), na = c("", "NA"), quoted_na = TRUE, quote = "\"", comment = "", trim_ws = TRUE, skip = 0, guess_max = chunk_size, progress = show_progress(), show_col_types = should_show_types(), skip_empty_rows = TRUE )
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, the input must be either wrapped with Using a value of |
callback |
A callback function to call on each chunk |
delim |
Single character used to separate fields within a record. |
chunk_size |
The number of rows to include in each chunk |
quote |
Single character used to quote strings. |
escape_backslash |
Does the file use backslashes to escape special
characters? This is more general than |
escape_double |
Does the file escape quotes by doubling them?
i.e. If this option is |
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 what |
locale |
The locale controls defaults that vary from place to place.
The default locale is US-centric (like R), but you can use
|
na |
Character vector of strings to interpret as missing values. Set this
option to |
quoted_na |
|
comment |
A string used to identify comments. Any text after the comment characters will be silently ignored. |
trim_ws |
Should leading and trailing whitespace (ASCII spaces and tabs) be trimmed from each field before parsing it? |
skip |
Number of lines to skip before reading data. If |
guess_max |
Maximum number of lines to use for guessing column types.
Will never use more than the number of lines read.
See |
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 |
show_col_types |
If |
skip_empty_rows |
Should blank rows be ignored altogether? i.e. If this
option is |
The number of lines in file
can exceed the maximum integer value in R (~2 billion).
Other chunked:
callback
,
melt_delim_chunked()
,
read_lines_chunked()
# Cars with 3 gears f <- function(x, pos) subset(x, gear == 3) read_csv_chunked(readr_example("mtcars.csv"), DataFrameCallback$new(f), chunk_size = 5)