Using regex in R to find strings as whole words (but not strings as part of words)

Question

I'm searching for the right regular expression. The following ``` t1 = c("IGF2, IGF2AS, INS, TH", "TH", "THZH", "ZGTH") grep("TH",t1, value=T) ``` returns all elements of `t1`, but only the first and second are correct. I just want entries with word/phrase `TH` returned?

Accepted Answer

You need to add word boundary anchors (`\b`) around your search strings so only entire words will be matched (i. e. words surrounded by non-word characters or start/end of string, where "word character" means `\w`, i.e. alphanumeric character).

Try

```
grep("\bTH\b",t3, value=T)
```

Using regex in R to find strings as whole words (but not strings as part of words)

Solution

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