CODEWITHSUNDEEP
rdataframe
nando_5g
nando_5g

Reputation: 41

Convert consecutive numbers in a R dataframe

I have a dataframe with consecutive values, is it possible to make = 0 the numbers after 1s?

df <- data.frame(a = c(0,0,0,0,1,1,1,0,0,0),
  b = c(0,0,1,1,1,1,0,0,0,0),
  c = c(1,1,0,0,0,0,0,1,1,0))

like this:

enter image description here

Upvotes: 2

Views: 102

Answers (4)

jblood94
jblood94

Reputation: 17011

We keep a 1 only if it is preceded by a 0 (a 1 on the first row will always be kept). We can do this by multiplying all but the first row by the negation of all but the last row (in R, we use negative indices to exclude an index).

df[-1,] <- df[-1,]*!df[-nrow(df),]
df
#>    a b c
#> 1  0 0 1
#> 2  0 0 0
#> 3  0 1 0
#> 4  0 0 0
#> 5  1 0 0
#> 6  0 0 0
#> 7  0 0 0
#> 8  0 0 1
#> 9  0 0 0
#> 10 0 0 0

Upvotes: 1

s_baldur
s_baldur

Reputation: 33548

We load data.table for the use of shift().

library(data.table)
df[] <- lapply(df, \(x) replace(x, shift(x, fill = 0) == 1, 0))
df
#    a b c
# 1  0 0 1
# 2  0 0 0
# 3  0 1 0
# 4  0 0 0
# 5  1 0 0
# 6  0 0 0
# 7  0 0 0
# 8  0 0 1
# 9  0 0 0
# 10 0 0 0

Upvotes: 0

maydin
maydin

Reputation: 3755

Applying diff function may be another altarnative with BaseR,

out <- rbind(df[1,],apply(df,2,diff))
out[out!=1] <- 0

gives,

#   a b c
#1  0 0 1
#2  0 0 0
#3  0 1 0
#4  0 0 0
#5  1 0 0
#6  0 0 0
#7  0 0 0
#8  0 0 1
#9  0 0 0
#10 0 0 0

Upvotes: 2

Ma&#235;l
Ma&#235;l

Reputation: 52239

library(dplyr)
df %>% 
  mutate(across(everything(), ~ +(.x == 1 & lag(.x, default = 0) != 1)))

output

   a b c
1  0 0 1
2  0 0 0
3  0 1 0
4  0 0 0
5  1 0 0
6  0 0 0
7  0 0 0
8  0 0 1
9  0 0 0
10 0 0 0

Upvotes: 2

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