Getting Even Columns from the Data Frame
The number of columns in a data frame in R can be fetched by the ncol() method. It returns the number of columns in the data frame. The modulo method can then be used with the integer 2 in R can be used to fetch the odd or even columns based on their indexes on the obtained vector. The corresponding column indices of the data frame are operated with a modulo method. The following syntax is used to fetch the odd rows of the data frame.
Syntax:
seq_len(cols)%%2
Data frame indexing method can then be used to obtain rows where the odd column index is equivalent to 0.
Syntax:
Data_frame[, odd_cols==0 ]
Example: select even columns from dataframe
R
# creating a data frame in R data_frame <- data.frame(col1 = 1:10, col2 = letters[1:10], col3 = rep(5:9,2)) print ("Original Dataframe") print(data_frame) # getting number of columns in R cols <- ncol(data_frame) # extracting odd rows even_cols <- seq_len(cols) %% 2 # getting data from odd data frame data_mod <- data_frame[, even_cols == 0] print ("even columns of dataframe") print(data_mod) |
Output:
[1] "Original Dataframe" col1 col2 col3 1 1 a 5 2 2 b 6 3 3 c 7 4 4 d 8 5 5 e 9 6 6 f 5 7 7 g 6 8 8 h 7 9 9 i 8 10 10 j 9 [1] "even columns of dataframe" [1] "a" "b" "c" "d" "e" "f" "g" "h" "i" "j"
Select Odd and Even Rows and Columns from DataFrame in R
In this article, we will discuss how to select odd and even rows from a dataframe in R programming language.