RowSums conditional on value
Clash Royale CLAN TAG#URR8PPPRowSums conditional on value
I'm rather new to r and have a question that seems pretty straight-forward.
I want to do rowSums but to only include in the sum values within a specific range (e.g., higher than 0).
e.g. - with the last column being the requested sum
col1 col2 col3 col4 totyearly
1 -5 3 4 NA 7
2 1 40 -17 -3 41
3 NA NA -2 -5 0
4 NA 1 1 1 3
What I currently have is:
df$totyearly <- rowSums(df[, 1:4], na.rm=TRUE)
How do I add the condition re positive values?
2 Answers
2
We can use replace to replace the values less than 0 to 0 and then take rowSums.
replace
rowSums
df$totyearly <- rowSums(replace(df, df < 0, 0), na.rm = TRUE)
df
# col1 col2 col3 col4 totyearly
#1 -5 3 4 NA 7
#2 1 40 -17 -3 41
#3 NA NA -2 -5 0
#4 NA 1 1 1 3
You could write your own custom sum function and apply it to each row:
apply
df <- read.table(text = "
col1 col2 col3 col4 totyearly
1 -5 3 4 NA 7
2 1 40 -17 -3 41
3 NA NA -2 -5 0
4 NA 1 1 1 3",
header = TRUE)
#define custom sum function
sum.pos <- function(x) sum(x[x > 0], na.rm = TRUE)
#apply it to each row
df$totyearly <- apply(df[ , 1:4], 1, sum.pos)
#or equivalently
df$totyearly <- apply(df[ , 1:4], 1, function(x) sum(x[x > 0], na.rm = TRUE))
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