is.list(rec[3]) # [1] TRUE # names()函数查看和修改元素名 names(rec) # [1] "name" "age" "scores" typeof(names(rec)) # [1] "character" names(rec)[names(rec)=="scores"]<-"三科分数" names(rec) # [1] "name" "age" "三科分数" rec$三科分数 # [1] 10 20 30 # 修改元素...
pname_list[i]<-paste('P',i,sep="") } #随机将道具名称传递到1W行上 orders$pname<-'P1'for(iin1:20){ orders[sample(1:nrow(orders),1000,replace=T),'pname']<-pname_list[i] } orders$pname<-as.factor(orders$pname) #随机将付费金额amount(1到50)传递到1W行上 orders$amount<-10for...
pname_list[i]<-paste('P',i,sep="") } #随机将道具名称传递到1W行上 orders$pname<-'P1'for(iin1:20){ orders[sample(1:nrow(orders),1000,replace=T),'pname']<-pname_list[i] } orders$pname<-as.factor(orders$pname) #随机将付费金额amount(1到50)传递到1W行上 orders$amount<-10for...
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list(name=“Joe”,salary=55000,union=T) 括号中分别为 标签=元素(又叫组件tag)的格式 列表索引的三种方法 j是列表 j$salary j[ [2] ] j[ ["salary"] ] 单括号返回列表(大),双括号返回组件(小) 双括号一次只能提取一个组件 列表变成向量
orders[sample(1:nrow(orders),1000,replace=T),'pname']<-pname_list[i] } orders$pname<-as.factor(orders$pname) 1. 2. 3. 4. 5. 6. 7. #随机将付费金额amount(1到50)传递到1W行上 orders$amount<-10 for(i in 1:50){ orders[sample(1:nrow(orders),1000,replace=T),'amount']<-i...
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A list in R is similar to yourto-do list at work or school: the different items on that list most likelydiffer in length, characteristic, type of activity that has to do be done, ... A list in R allows you to gather(收集) a variety of(各种各样的) objects under one name (that...
NAME<-HTML%>%html_nodes("#container>div.list-contents>div.list-results>div.key-list.imglazyload>div:nth-child(1)>div>a.lp-name>h3>span")NAME##{xml_nodeset(1)}##[1]东原旭辉璞阅 这样我们就获得了对应位置的节点。若想要得到对应节点的数据,可使用 html_text( ) 函数。 代码语言:javascript ...
我所拥有的: CLV_simple <- function (r, t, M, Alpha){ CLV = list() for (i in 0:t){ CLV[i] <- M*(Alpha/(1+r))^i return(sum(CLV)) } } CLV_simple(.10, 4, M, Alpha) 其中CLV=M*(Alpha/(1+r))^0,CLV1=M*(Alpha/(1+r))^1,依此类推4。 Alpha和M在前面被定义...