Loading Data into R

I have written about storing and retrieving objects in R language in my previous post. Lets see how to load data in R language here.

c Command

R offers a command called c, which stands for combine. It used to enter numeric, alphanumeric data.

> marks = c (100, 80, 85, 70, 35)

Following commands show how to load the numeric, alphabetic and alphanumeric data. See how R responds when you give alphanumeric data.

> marks = c (100, 80, 85, 70, 35)
> marks
[1] 100  80  85  70  35
> names = c("sun", "moon", "earth")
> names
[1] "sun"   "moon"  "earth"
> alphanu = c("sun", "moon", "earth", 2, 3)
> alphanu
[1] "sun"   "moon"  "earth" "2"     "3"    
> #append data
> marks = c(marks, 10, 20)
> marks
[1] 100  80  85  70  35  10  20
> #combine two objects
> combo = c(names, marks)
> combo
 [1] "sun"   "moon"  "earth" "100"   "80"    "85"    "70"    "35"    "10"    "20"

Scan command

We give the complete data as CSV when we use c command. Scan command helps us to enter the data interactively. Double enter to complete the data loading process.

> #scan numbers
> scan()
1: 10
2: 20
3: 30
4: 
Read 3 items
[1] 10 20 30
> scan(what='character')
1: tamil
2: english
3: maths
4: 
Read 3 items
[1] "tamil"   "english" "maths"

Loading single dimensional data from flat files

Scan shall be used to read your data files. I have a data file in D:/gandhari/videos/Advanced Business Analytics/marks.txt

Here is the way, we shall read the values.

> marks = scan(file = 'D:/gandhari/videos/Advanced Business Analytics/marks.txt')
Read 20 items
> marks;
 [1]  80  90 100 100  90  70  85  67  74  76  50  55  57  62  51  35  30  27  40  39

So scan forms everything as single dimension array.

I have given the complete path of the file in the above example. If you have multiple file in a same folder, it would be easier to change the working directory to ease the loading process. We shall give only the file name instead of the complete path.

> getwd()
[1] "D:/gandhari/documents"
> setwd("D:/gandhari/videos/Advanced Business Analytics/")

> marks = scan(file="marks.txt")

Loading multi-dimensional data from CSV file

How to load multi-dimensional array? Let’s use read.csv command.

This is my input file.

> marks<-read.csv(file = 'marks.csv', header = FALSE, sep = ",")
> marks
  V1 V2  V3  V4 V5
1 80 90 100 100 90
2 70 85  67  74 76
3 50 55  57  62 51
4 35 30  27  40 39

v1, v2, … v5 are variables

1, 2, … 5 are rows

R Studio data import

R Studio has an option to import the CSV files interactively using GUI.

Following is our input data

Follow the steps given below.