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I use dplyr package with a huge dataset. I need to add a new row in each group with a new level of certain factor, but at the same time, I want to repeat other variables from 1st existing row in each group.

str(cstock)
tibble [896 × 37] (S3: tbl_df/tbl/data.frame)
 $ ID        : chr [1:896] "1" "2" "3" "4" ...
 $ pl        : Factor w/ 42 levels "D1","D2","D3",..: 1 1 1 1 1 2 2 2 2 2 ...
 $ mxdpt     : num [1:896] 5.12 5.62 5.25 5.75 6.62 ...
 $ lyr       : chr [1:896] "NA" "NA" "NA" "NA" ...
 $ slyr      : Factor w/ 5 levels "lit","min20",..: 1 1 1 1 1 1 1 1 1 1 ...
 $ lthkn     : num [1:896] 5.12 5.62 5.25 5.75 6.62 ...
 $ bulk      : num [1:896] 0.0356 0.0518 0.0532 0.0413 0.0444 ...
 $ c         : num [1:896] 41.1 41.1 41.1 41.1 41.1 ...
 $ lstock    : num [1:896] 9.13 13.8 11.17 10.32 10.89 ...
 $ cstock    : num [1:896] 3.75 5.67 4.59 4.24 4.47 ...
 $ lcs_cm    : num [1:896] 0.731 1.008 0.873 0.737 0.675 ...

I want to add new row with new level "agrnd" to fctr 'slyr', but all the rest variables in new row should be repeated values from 1st row of each group.

I tried this:

cstock %>% 
  group_by(pl)%>%
  group_modify(~ add_row(.x, bulk = .$bulk[1], slyr = "agrnd")) 
cstock1$slyr<-as.factor(cstock1$slyr)

Resulting tibble

This code is working but is there any code that allows me to simply repeat 1st row without specifying them all? In my case 37 variables, I need to repeat most of them. Thanks for the advice!

M--
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SimonBoreal
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  • Hi, can you provide a reproducible example? https://stackoverflow.com/questions/5963269/how-to-make-a-great-r-reproducible-example – william3031 Mar 16 '23 at 22:22

1 Answers1

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A simple decision that I found myself.

cstock %>% group_by(pl) %>% slice(1) %>% mutate(slyr = "agrnd") %>% bind_rows(cstock, .)

SimonBoreal
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