重现了一下,似乎没什么问题?能否给出更为完整的示例代码和样本数据?
id <- c(
"TCGA-A6-2677-01.1", "TCGA-AA-3655-01", "TCGA-A6-2681-11", "TCGA-A6-3809-01.1",
"TCGA-AZ-6603-01", "TCGA-AA-3713-01", "TCGA-AZ-6601-01", "TCGA-A6-5665-01.1",
"TCGA-A6-2671-01", "TCGA-G4-6302-11", "TCGA-A6-3810-01", "TCGA-A6-5659-01.1",
"TCGA-AA-3494-11", "TCGA-AA-3496-01", "TCGA-G4-6311-01", "TCGA-A6-3810-01.1",
"TCGA-AA-3502-01", "TCGA-A6-4107-11", "TCGA-G4-6295-01", "TCGA-AA-3488-01"
)
substring(id, 1, 15)
#> [1] "TCGA-A6-2677-01" "TCGA-AA-3655-01" "TCGA-A6-2681-11" "TCGA-A6-3809-01"
#> [5] "TCGA-AZ-6603-01" "TCGA-AA-3713-01" "TCGA-AZ-6601-01" "TCGA-A6-5665-01"
#> [9] "TCGA-A6-2671-01" "TCGA-G4-6302-11" "TCGA-A6-3810-01" "TCGA-A6-5659-01"
#> [13] "TCGA-AA-3494-11" "TCGA-AA-3496-01" "TCGA-G4-6311-01" "TCGA-A6-3810-01"
#> [17] "TCGA-AA-3502-01" "TCGA-A6-4107-11" "TCGA-G4-6295-01" "TCGA-AA-3488-01"
<sup>Created on 2021-08-11 by the reprex package (v2.0.1)</sup>