来源：http://bbs.pinggu.org/thread-1219536-1-1.html

################ 生成数据 

bh=1:100

jxh=rep(1:17,c(4,5,6,7,8,4,5,6,7,8,4,5,5,5,6,7,8))

relation=c(0,5,6,10,0,5,6,10,11,0,5,6,10,11,12,0,5,6,10,11,12,13,0,5,6,10,11,12,13,14,

0,5,6,10,0,5,6,10,11,0,5,6,10,11,12,0,5,6,10,11,12,13,0,5,6,10,11,12,13,14,

0,5,6,10,0,5,6,10,11,0,5,6,10,11,0,5,6,10,11,0,5,6,10,11,12,0,5,6,10,11,12,13,

0,5,6,10,11,12,13,14)

nn=length(jxh) ##nn=100

jx=unique(jxh) ##jx=17

datajx=data.frame(jxh,relation,bh)

data1=data.frame(datajx[relation==5,])

data2=data.frame(datajx[relation==6,])

data1=data1[,-2]

data2=data2[,-2]

colnames(data1)[2]="did"

colnames(data2)[2]="mid"

data3=merge(datajx,data1,by.x="jxh",by.y="jxh")

data4=merge(data3,data2,by.x="jxh",by.y="jxh") ###data4=merge(data3,data2,by="jxh")

################ 不用for循环，实现赋值

data5 <- data4

data5[(relation == 5) | (relation == 6), 4:5] <- 0