标签：argument merge log set end eve ror ... 实战
8. 数据排序
> leadership$age
[1] 32 45 25 39 NA
> newdata <- leadership[order(leadership$age),]
> newdata
manager testDate country gender age item1 item2 item3 item4 item5
3 3 2008-10-01 UK F 25 3 5 5 5 2
1 1 2008-10-24 US M 32 5 4 5 5 5
4 4 2008-10-12 UK M 39 3 3 4 NA NA
2 2 2008-10-28 US F 45 3 5 2 5 5
5 5 2009-05-01 UK F NA 2 2 1 2 1
stringAsFactors agecat
3 FALSE Young
1 FALSE Young
4 FALSE Young
2 FALSE Young
5 FALSE <NA>
>
>
> attach(leadership)
The following objects are masked _by_ .GlobalEnv:
age, country, gender, manager
> newdata <- leadership[order(gender, age),]
> detach(leadership)
> newdata
manager testDate country gender age item1 item2 item3 item4 item5
3 3 2008-10-01 UK F 25 3 5 5 5 2
2 2 2008-10-28 US F 45 3 5 2 5 5
5 5 2009-05-01 UK F NA 2 2 1 2 1
1 1 2008-10-24 US M 32 5 4 5 5 5
4 4 2008-10-12 UK M 39 3 3 4 NA NA
stringAsFactors agecat
3 FALSE Young
2 FALSE Young
5 FALSE <NA>
1 FALSE Young
4 FALSE Young
>
> attach(leadership)
The following objects are masked _by_ .GlobalEnv:
age, country, gender, manager
> newdata <- leadership[order(gender, -age),]
> detach(leadership)
> newdata
manager testDate country gender age item1 item2 item3 item4 item5
5 5 2009-05-01 UK F NA 2 2 1 2 1
2 2 2008-10-28 US F 45 3 5 2 5 5
3 3 2008-10-01 UK F 25 3 5 5 5 2
4 4 2008-10-12 UK M 39 3 3 4 NA NA
1 1 2008-10-24 US M 32 5 4 5 5 5
stringAsFactors agecat
5 FALSE <NA>
2 FALSE Young
3 FALSE Young
4 FALSE Young
1 FALSE Young
>
9. 数据集的合并
9.1 添加列
> patientID <- c(1, 2, 3, 4)
> age <- c(25, 34, 28, 52)
> status <- c("poor", "improved", "excellent", "poor")
> gender <- c("F", "M", "M", "F")
> dataframeA <- data.frame(patientID, gender)
> dataframeA
patientID gender
1 1 F
2 2 M
3 3 M
4 4 F
> dataframeB <- data.frame(patientID, age, status)
> dataframeB
patientID age status
1 1 25 poor
2 2 34 improved
3 3 28 excellent
4 4 52 poor
> total <- merge(dataframeA, dataframeB, by="ID")
Error in fix.by(by.x, x) : ‘by‘ must specify a uniquely valid column
> total <- merge(dataframeA, dataframeB, by="patientID")
> total
patientID gender age status
1 1 F 25 poor
2 2 M 34 improved
3 3 M 28 excellent
4 4 F 52 poor
> total <- merge(dataframeA, dataframeB, by=c("gender", "age"))
Error in fix.by(by.x, x) : ‘by‘ must specify a uniquely valid column
> total <- merge(dataframeA, dataframeB, by=c("patientID", "age"))
Error in fix.by(by.x, x) : ‘by‘ must specify a uniquely valid column
>
> total <- cbind(dataframeA, dataframeB)
> total
patientID gender patientID age status
1 1 F 1 25 poor
2 2 M 2 34 improved
3 3 M 3 28 excellent
4 4 F 4 52 poor
>
9.2 添加行
> total <- rbind(dataframeA, dataframeB) Error in rbind(deparse.level, ...) : numbers of columns of arguments do not match
10. 数据集取子集
10.1 选入（保留）变量
10.2 剔除（丢弃）变量
10.3 选入观测
10.4 subset() 函数
10.5 随机抽样
标签：argument merge log set end eve ror ... 实战
原文地址：http://www.cnblogs.com/wnzhong/p/7496188.html
