仅打印字符串中与正则表达式匹配的部分

Question

我有400个包含多行的文件。我想找到特定的行，只提取/打印其中的一部分

我想达到以下目标：

Full seesion name: T27I5E8_S1_N005_V004

并仅打印：

S1_V004

我试过：

for filename in os.listdir(data_directory): 
     with open(data_directory + "/" + filename) as file:
        for line in file:
            if re.search(r'([S][\d])|([V][\d]{3})', line):
                    print(line)

但它打印出了整条线。 我还尝试：

  subjID = re.compile(r'([S][\d])|([V][\d]{3})')

for filename in os.listdir(data_directory): 
     with open(data_directory + "/" + filename) as file:
        for line in file:
            print(subjID.findall(line))

但输出结果如下所示：

  []
[]
[]
[]
[('S1', ''), ('', 'V094')]
[]
[]
[]
[]
[]
[]
[]
[('S1', ''), ('', 'V094')]
[]
[]
[]
[]
[]
[]
[]

Answer 1

你可以用

for filename in os.listdir(data_directory): 
  with open(data_directory + "/" + filename, 'r') as file:
    for line in file:
      m = re.findall(r'[SV]\d+', line)
      if len(m):
        print("_".join(m))

见Python demo和regex demo。使用re.findall，将找到所有匹配项，如果找到，则结果是由匹配文本组成的_连接字符串

图案细节

• [SV]-S或V
• \d+-1+位