Adding a column value based on row index in R

Question

I have the following data frame in R

> head(genes)
     Genes
1  APOBEC4
2  B3GALT2
3 C1orf127
4   CAMK1G
5   CAMTA1
6    EPHX1

I have a vector with row indexes.

> head(sig)
[1]  10  11  41  54 125 126

Now I want to add another columns to data frame genes, such that the rows at the index sig will get a values "Yes" and otherwise "NO"

Something like:

head(genes)
     Genes Sig
1  APOBEC4 NO
2  B3GALT2 NO
3 C1orf127 NO
4   CAMK1G NO
5   CAMTA1 NO
...
10  XXX    YES
...
41  YYY    YES

I tried but I could not find a solution.

I do not understand why people gives negative votes. Everyone is not expert on everything and may not have a basic understanding of other programming languages. I write python snippets and shell scripts, I analyze complex genomics data to understand even more complex biology behind it. Suddenly, If I ask a basic question in something where I do not have a clue, and its a bit urgent, people gets annoyed ? Cool. — gthm
– gthm, Commented Jan 9, 2017 at 11:22

akrun · Accepted Answer · 2017-01-09 11:02:12Z

2

We can simply use base R

genes$Sig <-  c("NO", "YES")[(seq_len(nrow(genes)) %in% sig) + 1]

Or with ifelse

genes$Sig <- ifelse(seq_len(nrow(genes)) %in% sig, "YES", "NO")

Or create a column with "NO" and then assign "YES" based on the index

genes$Sig <- "NO"
genes$Sig[sig] <- "YES"

edited Jan 9, 2017 at 11:02

answered Jan 9, 2017 at 10:59

akrun

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Comments

Ronak Shah · Accepted Answer · 2017-01-09 11:02:39Z

2

I am not sure, if you have rownames in your dataframe. We can use row_number() function in dplyr to check if the row is present in sig and assign the value accordingly

library(dplyr)
genes %>%
    mutate(Sig = ifelse(row_number() %in% sig, "YES", "NO"))

edited Jan 9, 2017 at 11:02

answered Jan 9, 2017 at 10:55

Ronak Shah

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Comments

Martin Gal · Accepted Answer · 2022-12-27 23:17:15Z

0

Try something like this:

library(dplyr)
genes <- genes %>%
    mutate(Sig = case_when(as.numeric(row.names(.)) %in% sig ~ "YES", TRUE ~ "NO"))

I used it like this and it worked for me.

SAC_FULL_MERGE <- SAC_FULL_MERGE %>% 
     mutate(Country = 
     case_when(as.numeric(row.names(.)) <= 135159 ~ "US", 
               as.numeric(row.names(.)) > 135159 ~ "CAN")) %>% 
     as.data.frame()

edited Dec 27, 2022 at 23:17

Martin Gal

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answered Dec 27, 2022 at 21:41

Trent Richens

1

1 Comment

benimwolfspelz Over a year ago

This could also be simplified a bit by using if_else (or ifelse from base R) instead of case_when: Country = if_else(as.numeric(row.names(.)) <= 135159, "US", "CAN")

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