replace y=1 if year>1980& year <1986
replace y=2 if year>=1986& year <=1990
replace y=3 if year>=1996& year <=2000
replace y=4 if year>=1996& year <=2000
replace y=5 if year>=2001& year <=2005
replace y=6 if year>=2006& year <=2010
replace y=7 if year>=2011& year <=2017

请问怎么把这个句子用简单命令实现，谢谢~