CODEWITHSUNDEEP
rsubstrgsub
Dinesh
Dinesh

Reputation: 663

Deleting specific characters in a data frame in R

I have data frame like following

>sample_df
dd_mav2_6541_0_10
dd_mav2_12567_0_2
dd_mav2_43_1_341
dd_mav2_19865_2_13
dd_mav2_1_0_1

I need to remove the all numbers after the foruth "_". I would like have the output like following

>sample_df
    dd_mav2_6541_0
    dd_mav2_12567_0
    dd_mav2_43_1
    dd_mav2_19865_2
    dd_mav2_1_0

I tried the following code but it only deletes specific number of characters but the not like the output as I mentioned above.

substr(sample_df,nchar(sample_df)-2,nchar(sample_df))

How can I get my output.

Upvotes: 0

Views: 712

Answers (2)

Davit Sargsyan
Davit Sargsyan

Reputation: 1284

# Create the vector (I added one more element 
# at the end, with less than 4 pieces)
sample_df <- c("dd_mav2_6541_0_10",
               "dd_mav2_12567_0_2",
               "dd_mav2_43_1_341",
               "dd_mav2_19865_2_13",
               "dd_mav2_1_0_1",
               "dd_mav2")

# Split by "_"
xx <- strsplit(x = sample_df, split = "_")
xx

[[1]]
[1] "dd_mav2_6541_0"

[[2]]
[1] "dd_mav2_12567_0"

[[3]]
[1] "dd_mav2_43_1"

[[4]]
[1] "dd_mav2_19865_2"

# Loop through each element and reconnect the pieces
yy <- lapply(xx, function(a) {
  if(length(a) < 4) {
    return(paste(a, collapse = "_"))
  } else {
    return(paste(a[1:4], collapse = "_"))
  }
})
yy

[[1]]
[1] "dd_mav2_6541_0"

[[2]]
[1] "dd_mav2_12567_0"

[[3]]
[1] "dd_mav2_43_1"

[[4]]
[1] "dd_mav2_19865_2"

# Re-create teh vector
do.call("c", yy)

[1] "dd_mav2_6541_0"  "dd_mav2_12567_0" "dd_mav2_43_1"   
    "dd_mav2_19865_2" "dd_mav2_1_0"     "dd_mav2"

Upvotes: 0

Cath
Cath

Reputation: 24074

you can try this:

gsub("_\\d+$","",sample_df)

It will remove the underscore and any number (at least one) of digits that follows it, at the end of a string.

With your data:

sample_df <- c("dd_mav2_6541_0_10","dd_mav2_12567_0_2","dd_mav2_43_1_341","dd_mav2_19865_2_13","dd_mav2_1_0_1")

gsub("_\\d+$","",sample_df)
#[1] "dd_mav2_6541_0"  "dd_mav2_12567_0" "dd_mav2_43_1"    "dd_mav2_19865_2" "dd_mav2_1_0"

Upvotes: 3

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