--- a
+++ b/R/XenaGenerate.R
@@ -0,0 +1,29 @@
+##' Generate and Subset a XenaHub Object from 'XenaData'
+##'
+##' @author Shixiang Wang <w_shixiang@163.com>
+##' @param XenaData a `data.frame`. Default is `data(XenaData)`.
+##' The input of this option can only be `data(XenaData)` or its subset.
+##' @param subset logical expression indicating elements or rows to keep.
+##' @return a [XenaHub] object.
+##' @export
+##' @examples
+##' # 1 get all datasets
+##' XenaGenerate()
+##' # 2 get TCGA BRCA
+##' XenaGenerate(subset = XenaCohorts == "TCGA Breast Cancer (BRCA)")
+##' # 3 get all datasets containing BRCA
+##' XenaGenerate(subset = grepl("BRCA", XenaCohorts))
+
+XenaGenerate <- function(XenaData = UCSCXenaTools::XenaData,
+                         subset = TRUE) {
+  enclos <- parent.frame()
+  subset <- substitute(subset)
+  row_selector <- eval(subset, XenaData, enclos)
+  XenaData <- XenaData[row_selector, ]
+
+  .XenaHub(
+    hosts = unique(XenaData$XenaHosts),
+    cohorts = unique(XenaData$XenaCohorts),
+    datasets = XenaData$XenaDatasets
+  )
+}