R：如何将数据框列中用分号分割的每个单词的首字母大写？

Question

假设我有一个数据框df。

> df <- data.frame(Disease = c('Disease Entry1; disease Entry2', 'disease Entry4','disease Entry5; disease entry6'), ID = c(1,2,3))
> df
                         Disease ID
1 Disease Entry1; disease Entry2  1
2                 disease Entry4  2
3 disease Entry5; disease entry6  3

我如何操作它，使每个疾病条目除了每个条目的第一个字母外都是小写的？即

> df
                         Disease ID
1 Disease entry1; Disease entry2  1
2                 Disease entry4  2
3 Disease entry5; Disease entry6  3

我假设我会以某种方式使用 tolower 函数，但是如何考虑分号？

Answer 1

可以先把所有字母转成小写，然后用gsub把BOS处或;后面的字母一起用后向引用\1转成大写\U:

df$Disease <- gsub("(?<=^|; )([a-z])", "\U\1", tolower(df$Disease), perl = T)

df
#                         Disease ID
#1 Disease entry1; Disease entry2  1
#2                 Disease entry4  2
#3 Disease entry5; Disease entry6  3

R：如何将数据框列中用分号分割的每个单词的首字母大写？

R: How to uppercase first letter of each word split by semicolon in data frame column?

r

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