Description Usage Arguments Details Value Examples
The function will read (as csv) approximately p*nlines lines. So
if p=.1
, then we will get roughly (probably not exactly) 10
data. This is the analogue of the base R function read.csv()
.
1 2 3 4 5 6 7 8 9 10 11 |
file |
Location of the file (as a string) to be subsampled. |
param |
The downsampling parameter. For the "proportional" method, this is the proportion to retain and should be a numeric value between 0 and 1. For the exact method, this is the total number of lines to read in. |
method |
A string indicating the type of read method to use. Options are "proportional" and "exact". |
reader |
A function specifying the reader to use. The default is
|
header |
Is a header (line of column names) on the first line of the csv file? |
nskip |
Number of lines to skip. If |
nmax |
Max number of lines to read. If nmax==0, then there is no read cap. Ignored
if |
verbose |
Should linecounts of the input file and the number of lines sampled be printed? |
... |
Additional arguments passed to the csv reader. |
This function scans over the test of the input file and at each step,
randomly chooses whether or not to include the current line into a
downsampled file. Each selected line is placed in a temporary file, before
being read into R via read.csv()
. Additional arguments to this
function (those other than file
, p
, and verbose
) are
passed to read.csv()
, and so if their behavior is unclear, you should
examine the read.csv()
help file.
If verbose=TRUE
, then something like:
Read 12207 lines (0.001%) of 12174948 line file.
will be printed to the terminal. This counts the header (if there is one) as one of the lines read and as one of the lines possible.
A dataframe, as with read.csv()
.
1 2 3 4 5 6 7 8 | library(filesampler)
file = system.file("rawdata/small.csv", package="filesampler")
# Read in a 5% random subsample of the rows.
data = sample_csv(file, param=.05)
# Read in 10 randomly sampled rows.
data = sample_csv(file, param=10, method="exact")
|
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