Created
April 9, 2018 21:46
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Tired of slow split()
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| splitByRow <- function(Y, f){ | |
| require(tidyverse) | |
| names <- dimnames(Y) | |
| Y <- as.matrix(Y); dimnames(Y) <- names | |
| #levels <- sort(unique(f)) %>% as.character | |
| temp <- split(Y, f=f) | |
| names <- names(temp) | |
| ns <- table(f)[names] | |
| temp <- lapply(1:length(temp), function(i){ | |
| x <- matrix(temp[[i]], ncol=ncol(Y), nrow=ns[[i]], byrow=FALSE) | |
| colnames(x) <- colnames(Y) | |
| x | |
| }) | |
| names(temp) <- names | |
| temp | |
| } | |
| splitByCol <- function(Y, f){ | |
| require(tidyverse) | |
| names <- dimnames(Y) | |
| Y <- as.matrix(Y); dimnames(Y) <- names | |
| #levels <- sort(unique(f)) %>% as.character | |
| temp <- split(t(Y), f=f) | |
| names <- names(temp) | |
| ns <- table(f)[names] | |
| temp <- lapply(1:length(temp), function(i){ | |
| x <- matrix(temp[[i]], nrow=nrow(Y), ncol=ns[[i]], byrow=TRUE) | |
| rownames(x) <- rownames(Y) | |
| x | |
| }) | |
| names(temp) <- names | |
| temp | |
| } |
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