Question

我有一个如下所示的数据框：

  project_counts <- read.table(
          text = "Project        Counts
                 'Old Patient'       4
                 'Old Customer'      2
                 'New Patient'       5
                 'Children'          3", 
          header=T)

我正在尝试创建一个名为＆＃34; Subject＆＃34;获取Count列并将其乘以2，基于匹配＆＃34; Project＆＃34;中的特定子字符串。柱。例如，如果Project有子串＆＃39; Old＆＃39;在其中我希望该行的主题列采用Count * 2，但如果它显示＆＃39; New＆＃39;我希望它取得Count * 4，但是如果它说'孩子＆＃39;我希望它采用Count * 5

我开始编写一个for循环，只是为了尝试使用＆＃39; Old＆＃39;子串，这是我得到的。似乎没有工作......

for (i in 1:length(project_counts$Project)) {
   if (grep('Old', project_counts$Project[i])) {
     project_counts$Subject <- project_counts$Counts*2
   }
}

Answer 1

看看ifelse声明。它可以用于检查连续的if-else场景，并将值分配给新列＆＃39; Subject＆＃39;。

project_counts <-  tibble::tribble(~Project,~Counts,
              'Old Patient',       4,
              'Old Customer',      2,
              'New Patient',       5,
              'Children',          3)

project_counts['Subject'] <- ifelse(substr(project_counts[['Project']],1,3)=='Old',project_counts[['Counts']]*2,ifelse(substr(project_counts[['Project']],1,3)=='New',project_counts[['Counts']]*4,ifelse(substr(project_counts[['Project']],1,8)=='Children',project_counts[['Counts']]*5,0)))

Answer 2

Project <- c('Old Patient',
             'Old Customer',
             'New Patient',
             'Children')

Counts <- c(4, 2, 5, 3)

project_counts <- data.frame(Project, Counts, stringsAsFactors = F)

project_counts$Subject <- ifelse(grepl('Old', project_counts$Project), 
                                 project_counts$Counts * 2,
                                 ifelse(grepl('New', project_counts$Project),
                                        project_counts$Counts * 4,
                                        project_counts$Counts * 5))

project_counts

##        Project Counts Subject
## 1  Old Patient      4       8
## 2 Old Customer      2       4
## 3  New Patient      5      20
## 4     Children      3      15

Answer 3

即使问题得到解答，我也试图提出一种更为通用的方法。看看

encapsulation: ViewEncapsulation.None

＃

.angular-cli.json

循环通过列赢得了工作？

3 个答案: