I hope you install the R and Rstudio successfully in your PC. Data manipulation in R is different from contemporary softwares for statistical – graphical analysis. Be in mind that R is not a software, rather it is a numerical computation program like MatLab or Octave. A detailed review on the capabilities of R were explained the post. Here we are going to start with basic data manipulation on R for extreme beginners. Let’s start with data( mtcars), which is usually an inbuilt dataset. To make you know how to import a data from your PC, just go to the link here.

car<- mtcars View(mtcars)

**Browsing through columns **

#### 1) Dollar method

Browse through your columns by adding $ symbol

car$

**2) Square bracket and number/name method**

Other methods are by using [] square brackets, or by using the exact column names(if you know) or by tab <=> button. However the result will be the same. Like maths, in R you can solve the same problems in different ways. Use the codes according to your convenience, and your data structure. Inside the [] , the data is represented by rows and columns.The basic structure is

data[rows,columns]

so here it is

car[,]

You could select desired columns by using “tab” button, when the cursor is in the square bracket[ ]. Similarly, you can shift the cursor left to the coma for rows.

you can use numbers instead of names of columns. i e, for the first column use 1 and for the second column use 2.

car[,1] # For first column car[2,]# For second column

Get first four columns from the data[car], you have to select multiple columns by using the command “c”.

car[,c(1,2,3,4)] # first four columns by using no.s. car[,c("mpg","cyl","disp","hp")] #first four columns by using names.

In the same way you can use rows too. Lets check the first 4 rows.

car[c(1,2,3,4),] # first four rows by number car[c("Mazda RX4","Mazda RX4 Wag","Datsun 710","Hornet 4 Drive"),]#first four rows by name

Everything in the R needs a name, as in real life scenario. Otherwise R will forgot, and won’t seen on global environment.

carpart<- car[,c(1,2,3,4)]

This way you can define the subsets, i e you made your own dataset from the previous one.

**Point data manipulation**

You can do point data editing in R, before you doing this you should have a better understanding on datasets you are dealing with. For this you have to specify both rows and columns.

just type

car[3,3] # 3rd row and 3rd column

check the output

[1] 108

Suppose you could change the value from 108 to 50

`car[3,3]<- 50`

**Change row names and column names**

Row names can be changed by function rownames(), lets the check the subset data “carpart” with rownames.

check result

```
rownames(carpart)
[1] "Mazda RX4" "Mazda RX4 Wag" "Datsun 710" "Hornet 4 Drive" "Hornet Sportabout"
[6] "Valiant" "Duster 360" "Merc 240D" "Merc 230" "Merc 280"
[11] "Merc 280C" "Merc 450SE" "Merc 450SL" "Merc 450SLC" "Cadillac Fleetwood"
[16] "Lincoln Continental" "Chrysler Imperial" "Fiat 128" "Honda Civic" "Toyota Corolla"
[21] "Toyota Corona" "Dodge Challenger" "AMC Javelin" "Camaro Z28" "Pontiac Firebird"
[26] "Fiat X1-9" "Porsche 914-2" "Lotus Europa" "Ford Pantera L" "Ferrari Dino"
[31] "Maserati Bora" "Volvo 142E"
```

If you want to know column names, you can use two commands

> colnames(carpart) # colnames is a specific function [1] "mpg" "cyl" "disp" "hp" > names(carpart)# names only work work for dataframes [1] "mpg" "cyl" "disp" "hp"

You can change the column names/row names by assign the new names in order, lets check the column names.

```
> names(carpart)
[1] "mpg" "cyl" "disp" "hp"
```

Now assign with new name.

names(carpart)<- c("miles/gal","cylinder","displacement","horsepower") # or colnames(carpart)<- c("miles/gal","cylinder","displacement","horsepower")

let’s check the new column names

I hope this will you make you start the R program from scratch, More advanced topics are coming soon. Please follow the category R-spells.