ofzhengyi 发表于 2015-3-4 10:43 
在R中
?grep

> grep("AL",data2$"statename")
[1] 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27
[28] 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54
[55] 55 56 57 58 59 60 61 62 63 64 65 66 67 68 69 70 71 72 73 74 75 76 77 78 79 80 81
[82] 82 83 84 85 86 87 88 89 90 91 92 93 94 95 96 97 98
> grep("AL",data2$"statename",value=T)
[1] "AL" "AL" "AL" "AL" "AL" "AL" "AL" "AL" "AL" "AL" "AL" "AL" "AL" "AL" "AL" "AL"
[17] "AL" "AL" "AL" "AL" "AL" "AL" "AL" "AL" "AL" "AL" "AL" "AL" "AL" "AL" "AL" "AL"
[33] "AL" "AL" "AL" "AL" "AL" "AL" "AL" "AL" "AL" "AL" "AL" "AL" "AL" "AL" "AL" "AL"
[49] "AL" "AL" "AL" "AL" "AL" "AL" "AL" "AL" "AL" "AL" "AL" "AL" "AL" "AL" "AL" "AL"
[65] "AL" "AL" "AL" "AL" "AL" "AL" "AL" "AL" "AL" "AL" "AL" "AL" "AL" "AL" "AL" "AL"
[81] "AL" "AL" "AL" "AL" "AL" "AL" "AL" "AL" "AL" "AL" "AL" "AL" "AL" "AL" "AL" "AL"
[97] "AL" "AL"
> grep("AL",data2,value=T)
named character(0)好像是不对,而且想把满足条件的整行都提取出来