Getting Even Rows from the Data Frame
The number of rows in a data frame in R can be fetched by the nrow() method. It returns the number of rows in the data frame. The seq_len() method is then applied to generate the integers beginning with 1 to the number of rows. The modulo method with the integer 2 in R can be used to fetch the odd or even rows based on their indexes on the obtained vector. The corresponding row 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(rows)%%2
Data frame indexing method can then be used to obtain rows where the even row index is equivalent to 0.
Syntax:
data_frame[odd_row == 0, ]
Example: Select even rows 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 rows in R rows <- nrow(data_frame) # extracting odd rows even_rows <- seq_len(rows) %% 2 # getting data from odd data frame data_mod <- data_frame[even_rows == 0, ] print ("even rows 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 rows of dataframe" > print(data_mod) col1 col2 col3 2 2 b 6 4 4 d 8 6 6 f 5 8 8 h 7 10 10 j 9
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.
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