R – Data Frames
R is an open-source programming language that is widely used as a statistical software and data analysis tool. DataFrames in R are generic data objects of R which are used to store the tabular data. Data frames can also be interpreted as mattresses where each column of a matrix can be of the different data types. DataFrame is made up of three principal components, the data, rows, and columns.
To create a data frame in R use
data.frame() command and then pass each of the vectors you have created as arguments to the function.
friend_id friend_name 1 1 Sachin 2 2 Sourav 3 3 Dravid 4 4 Sehwag 5 5 Dhoni
Get the Structure of the Data Frame
One can get the structure of the data frame using
str() function in R. It can display even the internal structure of large lists which are nested. It provides one liner output for the basic R objects letting the user know about the object and its constituents.
'data.frame': 5 obs. of 2 variables: $ friend_id : int 1 2 3 4 5 $ friend_name: chr "Sachin" "Sourav" "Dravid" "Sehwag" ... NULL
Summary of data in the data frame
In R data frame, the statistical summary and nature of the data can be obtained by applying
summary() function. It is a generic function used to produce result summaries of the results of various model fitting functions. The function invokes particular methods which depend on the class of the first argument.
friend_id friend_name Min. :1 Length:5 1st Qu.:2 Class :character Median :3 Mode :character Mean :3 3rd Qu.:4 Max. :5
Extract Data from Data Frame
Extract data from a data frame means that to access its rows or columns. One can extract specific column from a data frame using it’s column name.
friend.data.friend_name 1 Sachin 2 Sourav 3 Dravid 4 Sehwag 5 Dhoni
Expand Data Frame
A data frame in R can be expanded by adding new columns and rows to the already existing data frame.
friend_id friend_name location 1 1 Sachin Kolkata 2 2 Sourav Delhi 3 3 Dravid Bangalore 4 4 Sehwag Hyderabad 5 5 Dhoni Chennai
In R, one can perform various types of operation on a data frame like accessing rows and columns, selecting the subset of the data frame, editing data frames, delete rows and columns in a data frame, etc. Please refer to DataFrame Operations in R to know about all types of operations that can be performed on a data frame.