summary.hdd.RdProvides summary information -- i.e. dimension, size on disk, path, number of slices -- of hard drive data sets (HDD).
# S3 method for hdd
summary(object, ...)A HDD object.
Not currently used.
This function does not return anything. It only prints general information on the data set in the console.
Displays concisely general information on the HDD object: its size on disk, the number of files it is made of, its location on disk and the number of rows and columns.
Note that each HDD object contain the text file “_hdd.txt” in their folder also containing this information.
To obtain how the HDD object was constructed, use function origin.
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/file56886370696f/
#> 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"