Replace Row Information by Leading or Lagging Row – R

I have a large dataframe with rows that have duplicated first three columns (UnionChr, UnionStart, UnionEnd) and the remaining columns differ in values.

I ultimately want to just replace the N/A value with WT or DKO specific from the duplicated row and then remove the duplicated row, so my final data should look like this:

I can’t do a search/replace based Genotype and PeakType column because I have other rows that don’t have this duplicated problem that also have N/A. An additional problem is that the duplicated row is either leading or lagging, depending on the data set it came from.

I know I should use dplyr, and group by the first three columns, and somehow use lead/lag.

test <- df %>% 
  group_by(UnionChr, UnionStart, UnionEnd) %>% 
  mutate(??)

>Solution :

Here is one method

library(dplyr)
library(tidyr)
df %>% 
   mutate(PeakType = na_if(PeakType, "N/A"),
       indx = is.na(PeakType)) %>%
   group_by(UnionChr, UnionStart, UnionEnd) %>% 
   fill(PeakType, .direction = "downup") %>% 
  filter(indx) %>% 
  ungroup %>%
  select(-indx)

-output

# A tibble: 4 × 12
  UnionChr UnionStart UnionEnd IntersectChr IntersectStart IntersectEnd IntersectLe…¹ Inter…² Inter…³ Overlap Genot…⁴ PeakT…⁵
  <chr>         <int>    <int> <chr>                 <int>        <int> <chr>         <chr>   <chr>     <int> <chr>   <chr>  
1 chr1        3667144  3668013 chr1                3667144      3668013 870           20.60   dko_k2…     869 DKO     DKO Sp…
2 chr1        4478778  4479151 chr1                4478778      4479151 374           22.90   wt_k27…     373 WT      WT Spe…
3 chr1        4482327  4483301 chr1                4482327      4483301 975           22.77   dko_k2…     974 DKO     DKO Sp…
4 chr1        4483527  4483784 chr1                4483527      4483784 258           24.58   wt_k27…     257 WT      WT Spe…
# … with abbreviated variable names ¹​IntersectLength, ²​IntersectPileup, ³​IntersectName, ⁴​Genotype, ⁵​PeakType

data

df <- structure(list(UnionChr = c("chr1", "chr1", "chr1", "chr1", "chr1", 
"chr1", "chr1", "chr1"), UnionStart = c(3667144L, 3667144L, 4478778L, 
4478778L, 4482327L, 4482327L, 4483527L, 4483527L), UnionEnd = c(3668013L, 
3668013L, 4479151L, 4479151L, 4483301L, 4483301L, 4483784L, 4483784L
), IntersectChr = c(".", "chr1", "chr1", ".", ".", "chr1", "chr1", 
"."), IntersectStart = c(-1L, 3667144L, 4478778L, -1L, -1L, 4482327L, 
4483527L, -1L), IntersectEnd = c(-1L, 3668013L, 4479151L, -1L, 
-1L, 4483301L, 4483784L, -1L), IntersectLength = c(".", "870", 
"374", ".", ".", "975", "258", "."), IntersectPileup = c(".", 
"20.60", "22.90", ".", ".", "22.77", "24.58", "."), IntersectName = c(".", 
"dko_k27_peak_1", "wt_k27_peak_4", ".", ".", "dko_k27_peak_4", 
"wt_k27_peak_5", "."), Overlap = c(0L, 869L, 373L, 0L, 0L, 974L, 
257L, 0L), Genotype = c("WT", "DKO", "WT", "DKO", "WT", "DKO", 
"WT", "DKO"), PeakType = c("DKO Specific", "N/A", "N/A", "WT Specific", 
"DKO Specific", "N/A", "N/A", "WT Specific")), 
class = "data.frame", row.names = c(NA, 
-8L))