1.9 KiB
1.9 KiB
title
| title |
|---|
| Data Frames |
Data Frames
A data frame is an object in R.
Creating a Data Frame
You can create a data frame by combining vectors of the same length and using the function data.frame.
a <- c(1 ,2, 3, 4, 5) #vector a
b <- c("H", "E", "L", "L", "O") #vector b
c <- c(TRUE, FALSE, FALSE, TRUE, FALSE) #vector c
df <- data.frame(a, b, c)
NOTE: You can also import data from a various data file such as a csv file to a data frame. See Additional Resources below for help with that.
Adding Columns
To add a new column you can do df$new_column_name
Example
df$product <- 2 * df[,1]
You can alternatively have a vector with them same amount of elements as a column in df as use the function cbind to combine it to df.
product <- c(2, 4, 6, 8, 10)
df <- cbind(df, product)
Both ways will output the following table:
a b c product
1 1 H TRUE 2
2 2 E FALSE 4
3 3 L FALSE 6
4 4 L TRUE 8
5 5 O FALSE 10
Removing Columns or Rows
You can remove a column or row by using $ to specify a specific column name and making it NULL.
df$b <- NULL #column b in df is deleted
Alternatively you can delete a specific row by using df[row,] or delete a specific row by using df[,column].
Example
df[1,] <- NULL #Deletes first row in df
df[,2] <- NULL #Deletes second column in df