added utils file for dplyr pipe operator

        y <- Seurat::FetchData(X, group_by) %>% unlist %>% as.character()

    } else if (!group_by %in% names(SummarizedExperiment::colData(X))) {

        idx_use <- which(y %in% intersect(groups_use, y))

    group_pct <- sweep(group_nnz, 1, as.numeric(table(y)), "/") %>% t()

    group_pct_out <- -group_nnz %>%

        sweep(2, colSums(group_nnz) , "+") %>% 

        sweep(1, as.numeric(length(y) - table(y)), "/") %>% t()

    group_means <- sweep(group_sums, 1, as.numeric(table(y)), "/") %>% t()

    res <- Reduce(cbind, lapply(wide_res, as.numeric)) %>% data.frame()

    }) %>% unlist

    usigma <- sqrt(matrix(n1n2, ncol = 1) %*% matrix(rhs, nrow = 1))

#' Pipe operator

#'

#' @name %>%

#' @rdname pipe

#' @keywords internal

#' @export

#' @importFrom dplyr %>%

#' @examples

#' x <- 5 %>% sum(10)

#' 

#' @usage lhs \%>\% rhs

#' @return return value of rhs function. 

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