grep(pattern, x, ignore.case = FALSE, perl = FALSE, value = FALSE,
fixed = FALSE, useBytes = FALSE, invert = FALSE)
grepl(pattern, x, ignore.case = FALSE, perl = FALSE,
fixed = FALSE, useBytes = FALSE)
| 参数 | 取值说明 |
| ignore.case | 是否区分大小写 |
| perl | 是否使用perl规则 |
| fixed | 是否精确匹配 |
| value | FALSE返回对应的索引 |
| TRUE返回匹配到的结果 | |
| useBytes | FALSE匹配character-by-character |
|
| |
| invert | FALSE返回匹配到的 |
| TRUE返回没有被匹配的 | |
|
|
|
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|
> grep("[a-z]", letters)
[1] 1 2 3 4 5 6 7 8 9 10 11 12
[13] 13 14 15 16 17 18 19 20 21 22 23 24
[25] 25 26
> grep("[a-z]", letters,value = TRUE)
[1] "a" "b" "c" "d" "e" "f" "g" "h" "i"
[10] "j" "k" "l" "m" "n" "o" "p" "q" "r"
[19] "s" "t" "u" "v" "w" "x" "y" "z"
> txt<-c("Spark","RDD","Scala","MLlib","GraghX")
> grep("^S.*",txt,value = TRUE)
[1] "Spark" "Scala"
text<-c("ben@sina.com",
"kate@sina..com",
"ka...te@sina.com",
"kate@sina.12",
"kate@12.sina.com")
grep("\\w+@[[:alpha:]]+\\.[[:alpha:]]+",text,value=TRUE)