print.hdd.RdThis functions displays the first and last lines of a hard drive data set (HDD).
# S3 method for hdd
print(x, ...)A HDD object.
Not currently used.
Nothing is returned.
Returns the first and last 3 lines of a HDD object. Also formats the values displayed on screen (typically: add commas to increase the readability of large integers).
See hdd, sub-.hdd and cash-.hdd
for the extraction and manipulation of out of memory data. For importation of
HDD data sets from text files: see txt2hdd.
See hdd_slice to apply functions to chunks of data (and create
HDD objects) and hdd_merge to merge large files.
To create/reshape HDD objects from memory or from other HDD objects, see
write_hdd.
To display general information from HDD objects: origin,
summary.hdd, print.hdd,
dim.hdd and names.hdd.
# Toy example with iris data
iris_path = tempfile()
fwrite(iris, iris_path)
# destination path
hdd_path = tempfile()
# reading the text file with 50 rows chunks:
txt2hdd(iris_path, dirDest = hdd_path, rowsPerChunk = 50)
# creating a HDD object
base_hdd = hdd(hdd_path)
# Summary information on the whole data set
summary(base_hdd)
#> Hard drive data of 7.28 KB. Made of 3 files.
#> Location: C:/Users/lrberge/AppData/Local/Temp/Rtmpa0wfuK/file56886cdb2b21/
#> 150 lines, 5 variables.
# Looking at it like a regular data.frame
print(base_hdd)
#> Sepal.Length Sepal.Width Petal.Length Petal.Width Species
#> 1 5.1 3.5 1.4 0.2 setosa
#> 2 4.9 3 1.4 0.2 setosa
#> 3 4.7 3.2 1.3 0.2 setosa
#> ----
#> 148 6.5 3 5.2 2 virginica
#> 149 6.2 3.4 5.4 2.3 virginica
#> 150 5.9 3 5.1 1.8 virginica
dim(base_hdd)
#> [1] 150 5
names(base_hdd)
#> [1] "Sepal.Length" "Sepal.Width" "Petal.Length" "Petal.Width" "Species"