understanding sub function in R

Asked Apr 04 '18 at 19:54

Active Apr 04 '18 at 19:54

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I have a string like this "HsdkjnsjHlksmH". In the string, I want to replace only the second by a 'Q'.

I know this code sub("H*.H", "Q", s) can do it. But, I can't understand what the H*.H mean here.

Could someone explain please. I'm very new to R.

asked Apr 04 '18 at 19:54

thileepan

I think that you actually need `"H.*?H"` – G5W Apr 04 '18 at 19:56
See your pattern explanation [here](https://regex101.com/r/NVeLs8/1). – Wiktor Stribiżew Apr 04 '18 at 19:56
It says the * after H should match the character 'H' between 0 and unlimited times in the string. That means it should also match thr first occurrence of 'H'. Why doesn't that happen? – thileepan Apr 04 '18 at 20:06

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