R Read Table Txt All but Last Line

Reading Information From TXT|CSV Files: R Base Functions

  • Preleminary tasks
  • R base of operations functions for importing data
  • Reading a local file
  • Reading a file from internet
  • Summary
  • Related manufactures
  • Infos

Previously, we described the essentials of R programming and some all-time practices for preparing your data.

In this article, you'll learn how to import data from .txt (tab-separated values) and .csv (comma-separated values) file formats into R.

Reading Data From txt|csv Files: R Base Functions

R base of operations functions for importing information

The R base of operations function read.table() is a general function that tin can exist used to read a file in table format. The data will be imported equally a data frame.

Note that, depending on the format of your file, several variants of read.table() are available to make your life easier, including read.csv(), read.csv2(), read.delim() and read.delim2().


  • read.csv(): for reading "comma separated value" files (".csv").
  • read.csv2(): variant used in countries that employ a comma "," as decimal point and a semicolon ";" as field separators.
  • read.delim(): for reading "tab-separated value" files (".txt"). By default, signal (".") is used equally decimal points.
  • read.delim2(): for reading "tab-separated value" files (".txt"). By default, comma (",") is used every bit decimal points.

The simplified format of these functions are, as follow:

                # Read tabular data into R read.table(file, header = FALSE, sep = "", dec = ".") # Read "comma separated value" files (".csv") read.csv(file, header = TRUE, sep = ",", dec = ".", ...) # Or use read.csv2: variant used in countries that  # use a comma as decimal point and a semicolon as field separator. read.csv2(file, header = TRUE, sep = ";", december = ",", ...) # Read TAB delimited files read.delim(file, header = TRUE, sep = "\t", december = ".", ...) read.delim2(file, header = Truthful, sep = "\t", december = ",", ...)              

  • file: the path to the file containing the data to exist imported into R.
  • sep: the field separator graphic symbol. "\t" is used for tab-delimited file.
  • header: logical value. If TRUE, read.table() assumes that your file has a header row, so row 1 is the proper noun of each cavalcade. If that'southward not the case, you tin can add together the argument header = Faux.
  • dec: the graphic symbol used in the file for decimal points.

Reading a local file

  • To import a local .txt or a .csv file, the syntax would be:
                # Read a txt file, named "mtcars.txt" my_data <- read.delim("mtcars.txt") # Read a csv file, named "mtcars.csv" my_data <- read.csv("mtcars.csv")              

The above R code, assumes that the file "mtcars.txt" or "mtcars.csv" is in your current working directory. To know your current working directory, blazon the function getwd() in R console.

  • Information technology'due south as well possible to choose a file interactively using the function file.choose(), which I recommend if you're a beginner in R programming:
                # Read a txt file my_data <- read.delim(file.choose()) # Read a csv file my_data <- read.csv(file.choose())              

If you apply the R code above in RStudio, yous volition be asked to choose a file.

If your data contains cavalcade with text, R may assume that columns as a factors or group variables (e.chiliad.: "practiced", "proficient", "bad", "bad", "bad"). If you don't desire your text data to be converted as factors, add stringsAsFactor = FALSE in read.delim(), read.csv() and read.table() functions. In this case, the information frame columns corresponding to string in your text file volition be character.

For example:

                my_data <- read.delim(file.choose(),                        stringsAsFactor = Imitation)              
  • If your field separator is for case "|", it's possible utilise the general part read.table() with boosted arguments:
                my_data <- read.table(file.choose(),                        sep ="|", header = True, december =".")              

Reading a file from internet

It'south possible to apply the functions read.delim(), read.csv() and read.table() to import files from the web.

                my_data <- read.delim("http://www.sthda.com/upload/boxplot_format.txt") head(my_data)              
                                  Nom variable Grouping 1 IND1       ten     A 2 IND2        7     A 3 IND3       20     A 4 IND4       14     A 5 IND5       14     A 6 IND6       12     A              

Summary


  • Import a local .txt file: read.delim(file.choose())

  • Import a local .csv file: read.csv(file.choose())

  • Import a file from internet: read.delim(url) if a txt file or read.csv(url) if a csv file

Infos

This analysis has been performed using R (ver. 3.2.3).


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Source: http://www.sthda.com/english/wiki/reading-data-from-txt-csv-files-r-base-functions

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