R 获取每行字符串的特定部分

我有一个数据，我想采取具体的一部分

    DoseResponse_Curves/drCurve_AAATT.pdf
    DoseResponse_Curves/drCurve_AGMK1.pdf
    DoseResponse_Curves/drCurve_AGU.pdf
    DoseResponse_Curves/drCurve_ALH1L2.pdf
    DoseResponse_Curves/drCurve_ALKB1.pdf
    DoseResponse_Curves/drCurve_AS2.pdf
    DoseResponse_Curves/drCurve_ANK1.pdf
    DoseResponse_Curves/drCurve_ANKRD54.pdf

我只想拿第二次之后和之前的东西。这意味着输出如下所示

AAATT 
AGMK1
AGU
ALH1L2
ALKB1
AS2
ANK1
ANKRD54

---

注意：当我们处理基因名称时，它们可以包含字符，例如

c（“.”，“-”

您可以使用sub和正则表达式来实现这一点

Files = c(
    'DoseResponse_Curves/drCurve_AAATT.pdf',
    'DoseResponse_Curves/drCurve_AGMK1.pdf',
    'DoseResponse_Curves/drCurve_AGU.pdf',
    'DoseResponse_Curves/drCurve_ALH1L2.pdf',
    'DoseResponse_Curves/drCurve_ALKB1.pdf',
    'DoseResponse_Curves/drCurve_AS2.pdf',
    'DoseResponse_Curves/drCurve_ANK1.pdf',
    'DoseResponse_Curves/drCurve_ANKRD54.pdf')

sub(".*?_.*?_(.*?)\\..*", "\\1", Files)
[1] "AAATT"   "AGMK1"   "AGU"     "ALH1L2"  "ALKB1"   "AS2"     "ANK1"   
[8] "ANKRD54"

有很多方法：

# Example data with gene names with dots and dashes
Files = c('DoseResponse_Curves/drCurve_ALKB1.pdf',
          'DoseResponse_Curves/drCurve_BAC05914.1.pdf',
          'DoseResponse_Curves/drCurve_ALDH1L1-AS1.pdf',
          'DoseResponse_Curves/drCurve_AL953854.2-002.pdf')

# as parts of path are all same, we can sub with "":
gsub("DoseResponse_Curves/drCurve_|.pdf", "", Files)
# [1] "ALKB1"          "BAC05914.1"     "ALDH1L1-AS1"    "AL953854.2-002"

# Or, as we are working with path and filenames maybe:
gsub("drCurve_", "", tools::file_path_sans_ext(basename(Files)))
# [1] "ALKB1"          "BAC05914.1"     "ALDH1L1-AS1"    "AL953854.2-002"


# @G5W answer doesn't handle extra dots in gene names
sub(".*?_.*?_(.*?)\\..*", "\\1", Files)
# [1] "ALKB1"       "BAC05914"    "ALDH1L1-AS1" "AL953854"