r％in％运算符|控制案例敏感性 [英] r %in% operator | control case sensitivity

问题描述

是否可以控制％in％运算符的区分大小写?就我而言，无论输入如何，我都希望它返回true:

Is there a way to control the case sensitivity of the %in% operator? In my case I want it to return true no matter the case of the input:

stringList <- c("hello", "world")
"Hello" %in% stringList
"helLo" %in% stringList
"hello" %in% stringList

将此代码视为可复制的示例，但是在我的实际应用程序中，我还使用左侧的字符串列表，并检查stringList中是否存在单词.

Consider this code as a reproducible example, however in my real application I am also using a list of strings on the left and check for the presence of words from stringList.

推荐答案

使用grepl代替，因为它具有ignore.case参数:

Use grepl instead as it has an ignore.case parameter:

grepl("^HeLLo$",stringList,ignore.case=TRUE)
[1]  TRUE FALSE

第一个参数是正则表达式，因此它具有更大的灵活性，但必须以^开头并以$结尾，以避免拾取子字符串.

The first argument is a regular expression, so it gives you more flexibility, but you have to start with ^ and end with $ to avoid picking up sub-strings.

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