I have a file with 12 columns, which corresponds to 3 groups of 4 data, such as A1-B1-C1-D1-A2-B2-C2-D2-A3-B3-C3-D3 . I want to search when it is
A1[i]=A2[j]=A3[k]
and at the same time
B1[i]=B2[j]=B3[k]
When that happens, I want to save C1[i], D1[i], C2[j], D2[j], C3[k], D3[k] . The problem is that there are a lot of data (~ 600 thousand) and it takes a long time if I do not do it more efficiently than with for e if .