CODEWITHSUNDEEP
rdplyr
Alexander
Alexander

Reputation: 4645

how to change col names with the first row of a data in dplyr chain

I try to rename the column names with the first row of the data.

use first row data as column names in r

use %>% with replacement functions like colnames()<-

The problem that I counter is that doing this process without breaking the dplyr pipeline as I would like to continue doing some other stuff after renaming the columns.

There is comment in this post about rename function dplyr::rename may be more convenient if you are only (re)naming a few out of many columns (it requires writing both the old and the new name; see @Richard Scriven's answer)

However, in my real data the number of columns is not fixed and so I need to use something like to select the columns select(X9:max(ncol(.)))

df <- data.frame(replicate(10,sample(100,2,rep=TRUE)))


  X1 X2 X3 X4 X5 X6 X7 X8 X9 X10
1 77 40 45 98 75 17  5 33 53  94
2 43 67 82 42 63 90 14 65  4  98

library(dplyr)
df1 <- df %>%
  select(X8,X9,X10)%>%
  ....

the expected output after selection and renaming the columns

  33 53  94
1 65  4  98

Upvotes: 8

Views: 4452

Answers (4)

Ben Bolker
Ben Bolker

Reputation: 226587

Since I don't see this here and it seems to be simpler/more tidyverse-ish than other options: set_names(slice(.,1)) (to name by the first row; explicit coercion to character isn't necessary) followed by slice(-1) (to discard the first row since you don't need it any more) ...

library(tidyverse)
df1 <- (df 
    %>% select(X8:X10) 
    %>% set_names(slice(.,1)) 
    %>% slice(-1)
)

(set_names taken from @cropgen's answer)

Upvotes: 0

nsinghphd
nsinghphd

Reputation: 2022

You could do something like this

library(tidyverse)
df <- data.frame(replicate(10,sample(100,2,rep=TRUE)))
df
#>   X1 X2 X3 X4 X5 X6 X7 X8 X9 X10
#> 1 22 64 23 11 36 46 87 57 90  96
#> 2 62 46 15  9 77 84 70 32 71   8

cols_2_select <- c('X8','X9','X10')

df %>%
  select(all_of(cols_2_select)) %>% 
  set_names(df %>% select(all_of(cols_2_select)) %>% slice(1) %>% as.character()) %>% 
  slice(-1)
#>   57 90 96
#> 1 32 71  8

Created on 2021-04-16 by the reprex package (v1.0.0)

Upvotes: 2

Macosso
Macosso

Reputation: 1439

You can easily do it by naming columns as first row and then remove the first row.

library(dplyr)
df <- df %>%
  select(X8,X9,X10)

names(df) <- df[1,]
df <- df[-1,]

Upvotes: 2

jay.sf
jay.sf

Reputation: 73377

set.seed(502)
df <- data.frame(replicate(10, sample(100, 2, rep=TRUE)))

> df
  X1 X2 X3 X4 X5 X6 X7 X8 X9 X10
1 79  6 82 23 36 58 95 30 60  42
2 89 77  9 13 79 97  1 10 48  66

In base R we can do

df1 <- "colnames<-"(df[2 , x <- paste0("X", 8:10)], df[1, x])

> df1
  30 60 42
2 10 48 66

Upvotes: 0

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