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[英]R: How to write a function to do summation of a particular column values and report the row numbers when it meet certain criteria?
[英]In R: How do I set values that meet a certain criteria to a certain value
假設我在R中具有以下矩陣-優雅地,如何將所有小於0的值設置為零(例如)
[,1] [,2] [,3] [,4] [,5] [,6] [,7] [,8] [,9] [,10]
[1,] 0 1 3 5 9 11 15 17 21 27
[2,] -1 0 2 4 8 10 14 16 20 26
[3,] -3 -2 0 2 6 8 12 14 18 24
[4,] -5 -4 -2 0 4 6 10 12 16 22
[5,] -9 -8 -6 -4 0 2 6 8 12 18
[6,] -11 -10 -8 -6 -2 0 4 6 10 16
[7,] -15 -14 -12 -10 -6 -4 0 2 6 12
[8,] -17 -16 -14 -12 -8 -6 -2 0 4 10
[9,] -21 -20 -18 -16 -12 -10 -6 -4 0 6
[10,] -27 -26 -24 -22 -18 -16 -12 -10 -6 0
嘗試之一
m1[m1<0] <- 0
要么
m1 <- (m1 >=0)*m1
ifelse()
方法
# some data
m <- matrix((1:10)-5, ncol=5)
## [,1] [,2] [,3] [,4] [,5]
## [1,] -4 -2 0 2 4
## [2,] -3 -1 1 3 5
# setting values below zero to zero
ifelse(m < 0, 0, m )
## [,1] [,2] [,3] [,4] [,5]
## [1,] 0 0 0 2 4
## [2,] 0 0 1 3 5
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