語言使用課件4代碼

1、#創(chuàng)建leadership數(shù)據(jù)框manager - c(1, 2, 3, 4, 5)date - c(10/24/08, 10/28/08, 10/1/08, 10/12/08, 5/1/09)gender - c(M, F, F, M, F)age - c(32, 45, 25, 39, 99)q1 - c(5, 3, 3, 3, 2)q2 - c(4, 5, 5, 3, 2)q3 - c(5, 2, 5, 4, 1)q4 - c(5, 5, 5, NA, 2)q5 - c(5, 5, 2, NA, 1)leadership - data.frame(manager, date, gende

2、r, age, q1, q2, q3, q4, q5, stringsAsFactors = FALSE)# 刪除不再需要的元素rm(manager, date, gender, age, q1, q2, q3, q4, q5)#創(chuàng)建新變量mydata - data.frame(x1 = c(2, 2, 6, 4), x2 = c(3, 4, 2, 8)mydata$sumx - mydata$x1 + mydata$x2mydata$meanx - (mydata$x1 + mydata$x2)/2attach(mydata)mydata$sumx - x1 + x2mydata$meanx

3、 - (x1 + x2)/2detach(mydata)mydata 75 45 & leadership$age = 75 - Middle Agedleadership$agecatleadership$age = 45 - Young#方法二：leadership - within(leadership, agecat 75 = 55 & age = 75 - Middle Aged agecatage 55 - Young)# 變量重命名library(reshape)rename(leadership, c(manager = managerID, date = testDate)#

4、使用 is.na() 函數(shù)檢驗缺失值is.na(leadership, 6:10)#重編碼某些值為缺失值leadershipleadership$age = 99, age - NAleadership# 使用 na.omit()刪除缺失值的觀測newdata - na.omit(leadership)newdata#日期值mydates - as.Date(c(2015-3-17, 2014-11-11)# 將字符串轉(zhuǎn)換為日期strDates - c(01/05/1965, 08/16/1975)dates - as.Date(strDates, %m/%d/%Y)myformat - %m

5、/%d/%yleadership$date - as.Date(leadership$date, myformat)# 使用日期函數(shù)Sys.Date()date()today - Sys.Date()format(today, format = %B %d %Y)format(today, format = %A)#日期的計算startdate - as.Date(2004-02-13)enddate - as.Date(2009-06-22)days - enddate - startdate#使用函數(shù)difftime()來計算時間間隔，并以星期、天、時、分、秒來表示。today - Sys

6、.Date()dob - as.Date(1956-10-10)difftime(today, dob,units=”weeks”)# 類型轉(zhuǎn)換a - c(1, 2, 3)ais.numeric(a)is.vector(a)a - as.character(a)ais.numeric(a)is.vector(a)is.character(a)# 數(shù)據(jù)排序attach(leadership)newdata - leadershiporder(age), newdatadetach(leadership)attach(leadership)newdata - leadershiporder(gen

7、der, -age), newdatadetach(leadership)# 數(shù)據(jù)集取子集newdata - leadership, c(6:10)myvars - c(q1, q2, q3, q4, q5)newdata - leadershipmyvars# 剔除變量myvars - names(leadership) %in% c(q3, q4)newdata - leadership!myvarsnewdata - leadershipc(-7, -8)# 選入觀測newdata - leadership1:3, newdata 30), attach(leadership)newdata 30), detach(leadership)#建立在日期基礎上收集觀測leadership$date - as.Date(leadership$date, %m/%d/%y)startdate - as.Date(2009-01-01)enddate - as.Date(2009-10-31)newdata = startdate & lead