相关疑难解决方法(0)

我有这样的file1：

CHR                     SNP     TEST   A1   A2                 GENO   O(HET)   E(HET)            P 
   0         AFFX-SNP-000541      ALL    0    0                0/0/0      nan      nan            1
   0         AFFX-SNP-000541      AFF    0    0                0/0/0      nan      nan           NA
   0         AFFX-SNP-000541    UNAFF    0    0                0/0/0      nan      nan           NA
   0         AFFX-SNP-002255      ALL    0    0                0/0/0      nan      nan            1
   0         AFFX-SNP-002255      AFF    0    0                0/0/0      nan      nan           NA
   0         AFFX-SNP-002255    UNAFF    0    0                0/0/0      nan      nan           NA
   1                 rs12103      ALL    C    T           55/250/317   0.4019   0.4113       0.5596
   1                 rs12103      AFF    C    T                0/0/0      nan …

我想合并两个文件，例如如何根据两列的匹配合并两个文件？但一个文件可能无法包含所有结果。例如

文件1

1 dog
2 cat
3 fox
4 cow

文件2

1 woof
2 meow
4 mooh

想要的输出

1 dog woof
2 cat meow
3 fox
4 cow mooh