我有一个正则表达式问题。

我在下面有一个文件列表。

df <- c("Alilis CELF-4_CF_Data_Entry.xlsx" , "Ana T. CELF-4_CF_Data_Entry.xlsx" , "Ana V. CELF-4_CF_Data_Entry.xlsx","Anita CELF-4_CF_Data_Entry.xlsx")

[1] "Alilis CELF-4_CF_Data_Entry.xlsx" "Ana T. CELF-4_CF_Data_Entry.xlsx" "Ana V. CELF-4_CF_Data_Entry.xlsx" "Anita CELF-4_CF_Data_Entry.xlsx" 

我需要提取字符串开头的名称，但有一个带点的短字母(例如 Ana V.)我无法提取这些字母。

使用下面的代码，

unique(word(df, 1))
[1] "Alilis" "Ana"    "Anita" 

我怎样才能得到？

[1] "Alilis" "Ana T."  "Ana V."  "Anita"

最佳答案

尝试

gsub("^((\\S+)|^(\\w+ [A-Z]\\.))\\s+.*", "\\1", df)
[1] "Alilis" "Ana T." "Ana V." "Anita" 

如果有多个空格也应该有效

> gsub("^((\\S+)|^(\\w+ [A-Z]\\.))\\s+.*", "\\1", c(df, "Allis hello CELF-4_Data_Entry.xlsx"))
[1] "Alilis" "Ana T." "Ana V." "Anita"  "Allis" 

https://stackoverflow.com/questions/73831057/