how to write the script to know each sample's cluster number? I have followed the Seurat Tutorial:Integrating stimulated vs. control PBMC datasets to learn cell-type specific responses by using my data. And I am confused about how to write the script to calculate the cell number of each sample on each cluster. 

I have run TSENPlot to know the samples and I'm using another TSENPlot to get the clusters. If I want to know find the cluster1 of each sample's number how can I write the script?
Assuming you are following the basic seurat guide:

pbmc@ident


You can access the 'ident' slot of your Seurat object and you will get a vector of the cluster IDs and the names will be the respective cells.

head(seuratobj@ident)
Cell1A7 Cell1C4 Cell1D1 Cell1D2 Cell1D3 Cell1D5
0 3 3 1 3 1 
Levels: 0 1 2 3 4