Question

我想在文件中加入两行，根据它们是否以相同的元素开头我可以将每行的第一个元素转换为一个列表，并使用此列表中的元素来搜索每一行，但这似乎不是最有效的方法吗？

我有以下文件

1,AF534061.1,T,A  
1,K02718.1,T,A  
16,AF534061.1,G,-  
16,K02718.1,G,-  
17,AF534061.1,T,-  
17,K02718.1,T,-  
18,AF534061.1,A,-  
18,K02718.1,A,-  
19,AF534061.1,T,-  
19,K02718.1,T,-  
20,AF534061.1,A,-  
20,K02718.1,A,-  
21,AF534061.1,A,-   
21,K02718.1,A,-  
24,AF534061.1,C,T

如果第一项在行之间共享，我想加入行。所以我想得到以下输出

1,AF534061.1,T,A,1,K02718.1,T,A
16,AF534061.1,G,-,16,K02718.1,G,-
17,AF534061.1,T,-,17,K02718.1,T,-
18,AF534061.1,A,-,18,K02718.1,A,-
19,AF534061.1,T,-,19,K02718.1,T,-
20,AF534061.1,A,-,20,K02718.1,A,-
21,AF534061.1,A,-,21,K02718.1,A,-
24,AF534061.1,C,T

在这个例子中，看起来我可能只能加入其他所有行，但我希望（需要）使代码更通用！

我不认为这很难，但我似乎无法弄明白！谢谢你的帮助

Answer 1

Python标准库中充满了各种工具。对于此职位，请使用itertools.groupby。

import itertools

lines = '''1,AF534061.1,T,A
1,K02718.1,T,A
16,AF534061.1,G,-
16,K02718.1,G,-
17,AF534061.1,T,-
17,K02718.1,T,-
18,AF534061.1,A,-
18,K02718.1,A,-
19,AF534061.1,T,-
19,K02718.1,T,-
20,AF534061.1,A,-
20,K02718.1,A,-
21,AF534061.1,A,-
21,K02718.1,A,-
24,AF534061.1,C,T'''.split('\n')

for key, group in itertools.groupby(lines, lambda line: line.partition(',')[0]):
    print ','.join(group)

Answer 2

您可以使用正则表达式和反向引用。

print re.sub(r'(([^,]+).*)\n(\2.*\n)', r'\1\3', data)

以下是解释的表达式：

(             # Start of first line
 (            # Start of first part of line, refered to as \2
  [^,]+       # Everything before the first comma
 )
 .*           # Remainder of first line
)             # This new line isn't in any capture groups, so it'll be 
\n            #  removed from any matched results
(             # Start of second line
  \2          # This takes the first part of the first line and requires 
              #  it to match again
  .*          # Remainder of second line
  \n          # We include this newline to make the next search start at 
              #  the start of the following line.  It's reinserted because
              #  it's in the second line's capture group.
)

Answer 3

我没有测试过这段代码，但是这样的代码应该可以运行：

 common = {}
 for line in file.readLines():
   prefix = line.split(",")[0]
   if prefix in common:
     common[prefix].append(line)
   else:
     common[prefix] = [line]

 for key, values in common:
   print values.join(",")

Python：连接包含特定字符串的行

3 个答案: