cellchat需要两个输入：基因表达矩阵 + cell label。表达矩阵行为基因列为细胞，标准化+log。cell label为dataframe,行名为细胞，第一列为cell label.

从seurat v3 object中提取cell chat 所需要的两个输入文件：

data.input <- GetAssayData(seurat_object, assay = "RNA", slot = "data") # normalized data matrix
labels <- Idents(seurat_object)
meta <- data.frame(group = labels, row.names = names(labels)) # create a dataframe of the cell labels

library(CellChat)
library(patchwork)
options(stringsAsFactors = FALSE)

• part I: data input and preprocessing, initialization of the cellchat object 

（1）load data

# Here we load a scRNA-seq data matrix and its associated cell meta data
#load(url("https: