How to use summarise_at() method In R Language

Method 1: Using summarise_all() method

The summarise_at() affects variables that are extracted with a character vector or vars(). It applies the selected function to the data frame. The output data frame contains all the columns that are specified in the summarise_at method. In case all the columns of the data frame are mentioned, then the functionality of this method is the same as the summarise_all method.

data %>%
 summarise_at(vars(-cols(), ...), function)

Arguments :

data – The data frame to summarise the columns of
function – The function to apply on all the data frame columns.

R

library("dplyr") 
  
# creating a data frame 
df < - data.frame(col1=sample(rep(c(1: 5), each=3)), 
                  col2=1: 15, 
                  col3=letters[1:15]) 
  
print("original dataframe") 
print(df) 
  
# summarising the data 
print("summarised dataframe") 
df % >% 
summarise_at(c("col1", "col2"), mean, na.rm=TRUE) 

Output

[1] "original dataframe" 
col1 col2 col3 
1     3    1    a 
2     5    2    b 
3     4    3    c 
4     4    4    d 
5     5    5    e 
6     3    6    f 
7     2    7    g 
8     2    8    h 
9     1    9    i 
10    4   10    j 
11    2   11    k 
12    5   12    l 
13    1   13    m 
14    3   14    n 
15    1   15    o 
[1] "summarised dataframe" 
   col1 col2 
1    3    8