R sum element X in list of vector
A list of vectors of the same length can be summed with Reduce
:
Reduce(`+`, myListOfVector)
Putting it in a matrix
and using colSums
or rowSums
, as mentioned by @AnandaMahto and @JanLuba, might be faster in some cases; I'm not sure.
Side note. The example in the OP is not a list
; instead, it should be constructed like
myListOfVector <- list( # ... changing c to list on this line
c(1,2),
c(1,2),
c(1,2),
c(1,2)
)
Incognito
Updated on July 09, 2022Comments
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Incognito almost 2 years
I just started doing some R script and I can't figure out this problem.
I got a list of vector let say
myListOfVector <- list( c(1,2), c(1,2), c(1,2), c(1,2) )
what I want is the sum of each X element of each vector that are in my list base on the position of the element so that if I have 3 vector that contains (a, b, c), I will get the sum of each a, each b and each c in a list or vector
I know that each vector are the same length
What I seek is something like that
result <- sum(myListOfVector) # result must be c(4, 8)
Does anybody have an idea ?
The only way I've been able to do it is by using a loop but it take so much time that I can't resign to do it.
I tried some apply and lapply but they don't seem to work like I want it to because all I have is one vector at a time.
Precision : The list of vector is returned by a function that I can't modify I need an efficient solution if possible
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A5C1D2H2I1M1N2O1R2T1 over 8 yearsIf it's already in a
list
, then there might not be any performance advantage. ThecolSums
approach may even be slower because you'd have to convert the list to a matrix first.... +1