频数分布条形图

#读入数据并且查看数据集
dat=read.csv("UGdata.csv")
summary(dat)
id          name    sex      region          birth        income      
 201205A01: 1   高**   : 8   男:25   东部:16   1993-5-12 : 5   Min.   :  1.10  
 201205A02: 1   孙**   : 5   女:23   西部:17   1992-3-7  : 3   1st Qu.: 13.88  
 201205A03: 1   宋**   : 4           中部:15   1993-5-11 : 3   Median : 17.85  
 201205A04: 1   杨**   : 4                     1994-6-15 : 3   Mean   : 27.86  
 201205A05: 1   唐**   : 3                     1995-8-20 : 3   3rd Qu.: 34.17  
 201205A06: 1   吴**   : 3                     1996-10-24: 3   Max.   :158.00  
 (Other)  :42   (Other):21                     (Other)   :28                   
     height          weight          score      
 Min.   :147.0   Min.   :45.00   Min.   :46.80  
 1st Qu.:162.0   1st Qu.:62.00   1st Qu.:66.05  
 Median :166.5   Median :69.00   Median :74.00  
 Mean   :168.2   Mean   :68.96   Mean   :73.21  
 3rd Qu.:175.0   3rd Qu.:74.25   3rd Qu.:79.62  
 Max.   :191.0   Max.   :91.00   Max.   :96.00

1、将该群体的收入income划分为低中高三个等级，画条图显示频数分布；

# 对数据进行分组插入标签
dat$income.type[dat$income<=30]="低收入"
dat$income.type[dat$income>30&dat$income<=100]="中等收入"
dat$income.type[dat$income>100]="高收入"

a<-data.frame(table(dat$income.type))
x<-factor(a$Var1,levels = c("低收入","中等收入","高收入"))
barplot(Freq~x, data=a,main="群体收入频数分布柱状图",xlab="收入水平",ylab="频数",col=rainbow(3))

2、表格birth出生早于1992-3-7的同学的id、name和birth

dat$birth<-as.Date(dat$birth)
subset(dat,dat$birth>"1992-3-7",select=c(id,name,birth))

A data.frame: 40 × 3idnamebirth<fct><fct><date>

1201205A01赵**1992-04-08

2201205A02高**1993-05-12

3201205A03朱**1995-07-18

4201205A04许**1995-01-08

6201205A06吴**1995-11-27

7201205A07杨**1997-12-29

8201205A08宋**1995-08-20

.........

3、表格birth出生月份为3月的同学的id、name和birth

方法一

x<-c(grep(".*-03-.*",dat$birth))
dat[x,c(1,2,5)]

A data.frame: 6 × 3idnamebirth<fct><fct><date>5201205A05陈**1992-03-0711201205A11赵**1992-03-0712201205A12张**1992-03-0622201205A22赵**1992-03-0724201205A24王**1991-03-0434201205A34张**1992-03-06

方法二 （不可行） 原因是两向量长度不等，短的向量向唱的向量循环补齐

x<-c(grep(".*-03-.*",dat$birth,value = T))
subset(dat,dat$birth==x,select=c(id,name,birth))

A data.frame: 2 × 3idnamebirth<fct><fct><date>

12201205A12 张** 1992-03-06

22201205A22 赵** 1992-03-07