R 的 toTitleCase() 对 word "all"不起作用

Question

出于某种原因，R 的 toTitleCase()函数不适用于“all”这个词。任何想法为什么？

library(tools)
toTitleCase("all")  # gives "all"
toTitleCase("alt")  # gives "Alt"

Answer 1

帮助页面中的详细信息部分 ?toTitleCase注意到

Generally words in all capitals are left alone: this implementation knows about conventional mixed-case words such as ‘LaTeX’ and ‘OpenBUGS’ and a few technical terms which are not usually capitalized such as ‘jar’ and ‘xls’.

类型 toTitleCase没有括号进入您的控制台。您将看到一组异常(exception)词以及一个用于连接词的冗长正则表达式。其中有

either <- c("all", "above", "after", "along", "also", "among", 
        "any", "both", "can", "few", "it", "less", "log", "many", 
        "may", "more", "over", "some", "their", "then", "this", 
        "under", "until", "using", "von", "when", "where", "which", 
        "will", "without", "yet", "you", "your")

其中包含“所有”。