R：在第n个字符后按字母顺序对矢量进行排序

Question

我想按字母顺序对矢量的元素（字符串）进行排序，但只考虑第n个字符后的字符。字符串可以包含数字和字符，例如：

> v <- c("ENCSR529JNJ_HNR35NPK_21_K562", "ENCSR529MBZ_AP22IG_11_K562", "ENCSR529MBZ_AP22IG_21_K562", "ENCSR530BOP_DUPT6H_11_K562", "ENCSR530BOP_DUPT6H_21_K562")

并在第11个字符后排序后，v将变为：

"ENCSR529MBZ_AP22IG_11_K562", "ENCSR529MBZ_AP22IG_21_K562", "ENCSR530BOP_DUPT6H_11_K562", "ENCSR530BOP_DUPT6H_21_K562", "ENCSR529JNJ_HNR35NPK_21_K562"

任何帮助将不胜感激！感谢

Answer 1

v[order(substr(v, start = 12, stop = max(nchar(v))))]
# [1] "ENCSR529MBZ_AP22IG_11_K562"   "ENCSR529MBZ_AP22IG_21_K562"   "ENCSR530BOP_DUPT6H_11_K562"   "ENCSR530BOP_DUPT6H_21_K562"  
# [5] "ENCSR529JNJ_HNR35NPK_21_K562"

substr(v, start = 12, stop = max(nchar(v)))给出了省略前11个字符的子字符串。所以我们按此顺序。