R：在特定的行和列上循环自定义函数答案

【问题标题】：R: Looping a custom function over specific rows and columnsR：在特定的行和列上循环自定义函数
【发布时间】：2019-01-21 09:57:57
【问题描述】：

我想遍历选择的列及其所有行，并应用 If Else 嵌套函数以替换所有元素。

Table[c("Pb","Pc","Pd","Pe","Pf")] <-  lapply(Table[c("Pb","Pc","Pd","Pe","Pf")], function(x) {
                                       if (x <0.50) {round_any(x,0.05)}
                                  else if (x <1.00) {round_any(x,0.10)}
                                  else if (x <2.00) {round_any(x,0.25)}
                                  else if (x <5.00) {round_any(x,0.50)}
                                  else              {round_any(x,1)}
                                              })

代码运行，但我收到以下警告： 1: In if (x < 0.5) { ... : the condition has length > 1 and only the first element will be used结果并不完全符合我的预期。有没有其他方法可以产生这个输出？

【问题讨论】：

列的长度大于 1，if/else 仅适用于长度 1。您可能需要 ifelse
谢谢@akrun。我根据你的提示解决了它:)

标签： r apply lapply

【解决方案1】：

Table[c("Pb","Pc","Pd","Pe","Pf")] <- lapply(Table[c("Pb","Pc","Pd","Pe","Pf")], function(x) {
                                       ifelse (x <0.50, round_any(x,0.05),
                                       ifelse (x <1.00, round_any(x,0.10),
                                       ifelse (x <2.00, round_any(x,0.25),
                                       ifelse (x <5.00, round_any(x,0.50), 
                                               round_any(x,1)))))})

【讨论】：