You can use the following functions in R to display the size of a given data frame:
- nrow: Display number of rows in data frame
- ncol: Display number of columns in data frame
- dim: Display dimensions (rows and columns) of data frame
The following examples show how to use each of these functions in practice with the following data frame:
#create data frame df frame(team=c('A', 'B', 'C', 'D', 'E', 'F'), points=c(99, 90, 86, 88, 95, 99), assists=c(33, 28, 31, 39, 34, 25), rebounds=c(12, NA, 24, 24, 28, 33)) #view data frame df team points assists rebounds 1 A 99 33 12 2 B 90 28 NA 3 C 86 31 24 4 D 88 39 24 5 E 95 34 28 6 F 99 25 33
Example 1: Use nrow() to Display Number of Rows
The following code shows how to use the nrow() function to display the total number of rows in the data frame:
#display total number of rows in data frame
nrow(df)
[1] 6
There are 6 total rows.
Note that we can also use the complete.cases() function to display the total number of rows with no NA values:
#display total number of rows in data frame with no NA values nrow(df[complete.cases(df), ]) [1] 5
There are 5 total rows that have no NA values.
Example 2: Use ncol() to Display Number of Columns
The following code shows how to use the ncol() function to display the total number of columns in the data frame:
#display total number of columns in data frame
ncol(df)
[1] 4
There are 4 total columns.
Example 3: Use dim() to Display Dimensions
The following code shows how to use the dim() function to display the dimensions (rows and columns) of the data frame:
#display dimensions of data frame
dim(df)
[1] 6 4
This tells us there are 6 rows and 4 columns in the data frame.
You can also use brackets with the dim() function to display only the rows or columns:
#display number of rows of data frame dim(df)[1] [1] 6 #display number of columns of data frame dim(df)[2] [1] 4
Additional Resources
The following tutorials explain how to perform other common tasks in R:
How to Use rowSums() Function in R
How to Apply Function to Each Row in Data Frame in R
How to Remove Rows from Data Frame in R Based on Condition