无法用R语言

Question

string1<-"ccjar_neutral v_neutral vaux_neutral nnp_neutral prn_neutral v_neutral inj_neutral"

如何将正则表达式写入

1. 仅提取＆＃34; v_neutral＆＃34;来自string1

2. 提取＆＃34; v_neutral vaux_neutral＆＃34;来自string1

Answer 1

我的猜测......

str_extract_all(string1, "\\b(v\\w+)(?:\\s+v\\w+)\\b")[[1]]
# [1] "v_neutral vaux_neutral"
str_extract_all(string1, "\\b(v\\w+)(?=\\s+v\\w+)\\b")[[1]]
# [1] "v_neutral"