如何比较两个文件并打印仅匹配第一个文件的第二个文件

Question

我有两个文件。一个有两列，ref.txt。另一个有三列，file.txt。

在 ref.txt 中，

1  2
2  3
3  5

在file.txt中，

1  2  4   <---here matching
3  4  5
6  9  4
2  3  10  <---here matching
4  7  9
3  5  7   <---here matching

我想比较每个文件的两列，然后只打印 file.txt 中与 ref.txt 匹配的行。

所以，输出应该是，

1  2  4
2  3  10
3  5  7

我认为两个字典比较之类的，

mydict = {}
mydict1 = {}

with open('ref.txt') as f1:
     for line in f1:
         key, key1 = line.split()
         sp1 = mydict[key, key1]

with open('file.txt') as f2:
      for lines in f2:
          item1, item2, value = lines.split()
          sp2 = mydict1[item1, item2]
          if sp1 == sp2:
             print value

如何将两个文件与字典或其他文件进行适当的比较？

我找到了一些 perl 和 python 代码来解决两个文件中相同数量的列。

在我的例子中，一个文件有两列，另一个有三列。

如何比较两个文件，只打印匹配的值？

Answer 1

这是另一个选择：

use strict;
use warnings;

my $file = pop;
my %hash = map { chomp; $_ => 1 } <>;

push @ARGV, $file;

while (<>) {
    print if /^(\d+\s+\d+)/ and $hash{$1};
}

用法：perl script.pl ref.txt file.txt [>outFile]

最后一个可选参数将输出定向到文件。

数据集的输出：

1  2  4
2  3  10
3  5  7

希望这会有所帮助！

Answer 2

grep -Ff ref.txt file.txt

如果两个文件中字符之间的空格量相同，则

就足够了。如果不是，你可以这样做

awk '{print "^" $1 "[[:space:]]+" $2}' | xargs -I {} grep -E {} file.txt

结合我最喜欢的三个实用程序：awk、grep 和 xargs... 后一种方法还确保匹配只发生在行首（比较第 1 列和第 1 列，以及第 2 列与第 2 列）。

Answer 3

这是一个经过修改和注释的版本，应该适用于您的更大数据集：

#read in your reference and the file
reference = open("ref.txt").read()
filetext = open("file.txt").read()

#split the reference file into a list of strings, splitting each time you encounter a new line
splitReference = reference.split("\n")

#do the same for the file
splitFile = filetext.split("\n")

#then, for each line in the reference,
for referenceLine in splitReference:

  #split that line into a list of strings, splitting each time you encouter a stretch of whitespace
  referenceCells = referenceLine.split()

  #then, for each line in your 'file',  
  for fileLine in splitFile:

    #split that line into a list of strings, splitting each time you encouter a stretch of whitespace
    lineCells = fileLine.split()

    #now, for each line in 'reference' check to see if the first value is equal to the first value of the current line in 'file'
    if referenceCells[0] == lineCells[0]:

      #if those are equal, then check to see if the current rows of the reference and the file both have a length of more than one
      if len(referenceCells) > 1:
        if len(lineCells) > 1:

          #if both have a length of more than one, compare the values in their second columns. If they are equal, print the file line
          if referenceCells[1] == lineCells[1]:
            print fileLine

输出：

1  2  4
2  3  10
3  5  7