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[英]dividing first row of each matrix in list of matrices by the lagged sum of all rows in each matrix of a list matrices
[英]In R, with a list of matrices, how can I quickly find the difference between the first and second row in each matrix in the list?
假設我有一個類似以下的列表:
my.list <- replicate(100, matrix(rnorm(50), nrow = 2), simplify = FALSE)
其中包含100個元素,每個元素都是2 x 25矩陣。 我想找到數組中每個矩陣的第二行和第一行之間的差異。 因此,看一下第一個矩陣,即:
> my.list[[1]]
[,1] [,2] [,3] [,4] [,5] [,6] [,7] [,8]
[1,] -0.6439385 -1.0432182 -0.8209565 -0.39554834 0.11923593 -0.7924756 0.9486538 -0.5773245
[2,] -0.2485357 0.3248831 0.0510696 -0.01372084 -0.03815523 -2.0050425 1.0868125 -2.5684173
[,9] [,10] [,11] [,12] [,13] [,14] [,15] [,16]
[1,] -0.2007935 -0.4698965 -1.2655670 -0.09743834 -0.1665144 0.2858232 -1.5013000 1.3658686
[2,] 0.7978383 0.1259687 -0.0956009 1.63116327 -2.6593684 1.5665240 0.8206011 0.1437499
[,17] [,18] [,19] [,20] [,21] [,22] [,23] [,24]
[1,] 1.0984398 1.423985 -1.4280701 -0.3175241 0.3076809 -1.9266312 -0.2429406 -0.9616004
[2,] -0.6761191 1.201523 -0.4578632 1.8785372 -0.2124522 -0.9074403 -0.9615636 1.4551716
[,25]
[1,] -0.2794859
[2,] -0.9004094
我想得到:
my.list[[1]][2,]-my.list[[1]][1,]
[1] 0.3954028 1.3681013 0.8720261 0.3818275 -0.1573912 -1.2125669 0.1381587 -1.9910928
[9] 0.9986318 0.5958652 1.1699661 1.7286016 -2.4928540 1.2807008 2.3219011 -1.2221187
[17] -1.7745590 -0.2224617 0.9702069 2.1960613 -0.5201331 1.0191909 -0.7186231 2.4167720
[25] -0.6209235
但對於所有矩陣。 有沒有簡單的方法可以做到這一點? 謝謝。
您可以使用lapply
計算每個矩陣的減法
lapply(my.list, function(x) x[2,]-x[1,])
或另一個選擇是
library(purrr)
map(my.list, ~ c(diff(head(.x, 2))))
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