[英]Extracting patterns from text in R
我的数据如下:
t <- "The data is like hi hi hi hi and hi hi end"
我的正则表达式是:
grammer <- "[[:space:]]*(hi)+[[:space:]]"
执行以下两行后:
res <- gregexpr(grammer, t)
regmatches(t, res)
我有输出:
[[1]]
[1] " hi " "hi " "hi " "hi " " hi " "hi "
但是,我想要的东西是: " hi hi hi hi "
和" hi hi "
你可以这样做,
> t<-"The data is like hi hi hi hi and hi hi end"
> grammer<-"[[:space:]]*(hi[[:space:]])+[[:space:]]*"
> res<-gregexpr(grammer, t)
> regmatches(t, res)
[[1]]
[1] " hi hi hi hi " " hi hi "
要么
> grammer<-"[[:space:]]*(hi[[:space:]])+"
> res<-gregexpr(grammer, t)
> regmatches(t, res)
[[1]]
[1] " hi hi hi hi " " hi hi "
要么
> t <- "The data is like hi hi hi hi and hi hi end hi"
> grammer<-"[[:space:]]*(hi\\>[[:space:]]?)+"
> res<-gregexpr(grammer, t)
> regmatches(t, res)
[[1]]
[1] " hi hi hi hi " " hi hi " " hi"
没有领先或跟随空格。
> t <- "The data is like hi hi hi hi and hi hi end hi"
> grammer<-"hi\\>([[:space:]]hi)*"
> res<-gregexpr(grammer, t)
> regmatches(t, res)
[[1]]
[1] "hi hi hi hi" "hi hi" "hi"
说明:
[[:space:]]*
匹配空格字符零次或多次。 (hi[[:space:]])+
匹配字符串hi
和后续空格一次或多次。
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