Off topic:How to get the one upper and one lower numbers

Question

[Kumar]

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I have two tab delimited files that are containing numbers in first two rows, I am looking to compare these files and need to grep one lower and one greater numbers in file 2 based on numbers in file 1. please suggest perl/python script.

For example:

File 1:

19951   19901
20918   20868

File 2:

17464   19446   ID=LGE3207
16948   17388   ID=LGE3208
17621   18583   ID=LGE3208
18580   19785   ID=LGE3208
20156   20371   ID=LGE3208
20544   20795   ID=LGE3208
18588   19550   ID=LGE3207
20701   20752   ID=LGE3207
21123   21338   ID=LGE3207
21511   21762   ID=LGE3207
17096   18232   ID=LGE3207
14500   14715   ID=LGE3207

DESIRE OUTPUT:

18580   19785   ID=LGE3208
20156   20371   ID=LGE3208
19547   20752   ID=LGE3207
21123   21338   ID=LGE3207