Repeat rows with specific value

user_14518614 0
Viewed 175

I would like to repeat rows contain specific values in R with df as below

df <- data.frame(name1 = c("x","y","z"),
                 name2 = c(0,1,2))
df

  name1 name2
1     x     0
2     y     1
3     z     2

My desired output

  name1 name2
1     x     0
2     x     0
3     y     1
4     y     1
5     z     2

I would like to say only rows containing 'x' and 'y' will be repeated one time. So far, I only came up with the idea of using add_row and replace NA values by the corresponding values. Any sugesstions for this using tidyverse?

dplyr r
5 Answers

We could do it this way:

library(dplyr)
df %>% 
  filter(name1=="x" | name1=="y") %>% 
  bind_rows(df) %>% 
  arrange(name1)


  name1 name2
1     x     0
2     x     0
3     y     1
4     y     1
5     z     2
user_133216470

We may also do this as

library(dplyr)
library(tidyr)
df %>%  
   uncount(1 +(name1 %in% c('x', 'y')))
  name1 name2
1     x     0
2     x     0
3     y     1
4     y     1
5     z     2
user_37322710

I just couldn't remember, but I thought there was a shorter way to do this:

df[sort(c(seq_len(nrow(df)), rep(which(df$name1 %in% c("x", "y")), 1))),]

    name1 name2
1       x     0
1.1     x     0
2       y     1
2.1     y     1
3       z     2
user_143145200

You can create a new column specifying number of times a row should be repeated and then use uncount to repeat them.

library(dplyr)
library(tidyr)

df %>%
  mutate(repeat_row = ifelse(name1 %in% c('x', 'y'), 2, 1)) %>%
  uncount(repeat_row)

#  name1 name2
#1     x     0
#2     x     0
#3     y     1
#4     y     1
#5     z     2
user_39629140

You can do this using tidyr::add_row, but describe what you want to put into the row by using indexing.

library(tidyverse)
df <- data.frame(name1 = c("x","y","z"),
                 name2 = c(0,1,2))
df %>% 
  add_row(df[1,], .before = 2) %>% 
  add_row(df[2,], .before = 3)
user_142190380
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