提取包含特定字符或字符链的整个单词。

Question

我想从“句子”中提取一串字符。我试过用str_extract，但是我找不到好的reg。不过，我想知道是否还有其他方法可以做到。

下面是一些我用过的句子的例子：

sentence <- 
c("PT AT FB AT MQ LGMS PF PRVNCL 1CT 200G *",
"PT AT FB AT MQ SC CLS PF BBQ 1CT 200G *",
"PT AT FB AT MQ SC CLS PF BSQ 1CT 200G *",
"AT FB AT MQ SC CLS PF TX MX 1CT 200G * I",
"PR FCLNTS PT HNZ LGMS MF BSLC 2CT 490G *",
"FCLNTS PT HNZ LGMS MF ARRBT 2CT 490G * I",
"FCLNTS PT HNZ PST MF PST RG 2CT 490G * I",
"LGMS MF PVRNS GRLLS & FRMG IT 2CT 490G *")

我需要提取每一个"numG"，这意味着每一个200G，490G，.等

Answer 1

如果每个"numG"中只有一个sentence，则可以使用sub

sub(".*?(\\d+G).*", "\\1", sentence)
#[1] "200G" "200G" "200G" "200G" "490G" "490G" "490G" "490G"

如果它们将是多个，则可以使用来自stringr的stringr

stringr::str_extract_all(sentence, "\\d+G")

或

regmatches(sentence, gregexpr("\\d+G", sentence))