Abdoul Blog - Base R Essentials

This second blog post of the series focuses on reading and writing files of different formats. Although most of the functions focus on reading and writing tabular data, there are also functions to extend the principles to plain text.

Functions	Tasks / Examples
`load("filepath")`	reloads dataset written with the function `save`
`data(x)`	loads the dataset `x`
`readLines(con, n)`	read some some or all text lines from connection, where `con` is supposed to be a connection object, but when it is a string, it is considered as a file path. `n` is the maximal number of lines to read
`read.table("filepath")`	reads tabular data transforming it to a data frame. There are multiple arguments: - `sep`: to specify the separator - `header`: a boolean (`TRUE` or `FALSE`) to take the first row or not - `skip`: an integer `n` to indicate the number of rows to skip Ex: `read.table("weight.txt", sep = ",", header = T, skip = 5)`
`read.csv("filepath")`	same that `read.table` except that there are predefined arguments values to read CSV (Comma Separated Values) files
`read.csv2("filepath")`	same as `read.csv` except the `dec`¹ argument default value is `,` here and `.` in case of `read.csv`
`read.delim("filepath")`	same as `read.table` except that there are predefined arguments values to read values separated by tabulations
`read.fwf("filepath", widths)`	reads a table of fixed width formatted² data a into data frame. The `widths` argument is an integer vector, giving the widths of the fixed-width fields.
`save( x, y, file = "file.RData")`³	writes an external representation of objects `x` and `y` to the specified file. The objects can be read back from the file at a later date by using the function `load`.
`save.image()` or `save.image(file = "file.RData")`	same as `save` except that it saves all the environment objects in `.RData` file if `file` argument is not specified, else in `file`.
`cat(..., file = "filepath")`	outputs the objects, concatenating the representations in the `file` specified. Ex: `cat(x, y, file = "xy.txt")` converts `x` and `y` objects to characters and writes that representation in the file `xy.txt`.
`print(x, ... )`	prints the object `x`. The printing format varies according to the argument class.
`format(x, ...)`	format `x` for pretty printing. There are several options to fit your need. Ex: `format(13.7, nsmall = 3)` to indicate the minimum number of digits to the right of the decimal point. Feel free to look at the others options `help(format)`.
`writeLines(text, con)`	writes the the character vector `text` in the connection object `con` of the file path given by `con` if it is a string
`write.table(x, file = "filepath")`	convert `x` to a data frame if it is not and writes it to the `file` specified. In the same way, there are various other functions(`write.csv`, `write.csv2` and many others) for different outputs.

Footnotes

the character used in the file for decimal points↩︎
The format is designed to allow for saving of textual information/data in an organized fashion.↩︎
.RData is a binary file format specific to R.↩︎

Citation

BibTeX citation:

@online{issabida2023,
  author = {Abdoul ISSA BIDA},
  title = {Base {R} {Essentials} - {Part} 2},
  date = {2023-02-17},
  url = {https://www.abdoulblog.com},
  langid = {en}
}

For attribution, please cite this work as:

Abdoul ISSA BIDA. 2023. “Base R Essentials - Part 2.” February 17, 2023. https://www.abdoulblog.com.