CODEWITHSUNDEEP
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Nottles82
Nottles82

Reputation: 103

Make only numeric entries blank

I have a dataframe with UK postcodes in it. Unfortunately some of the postcode data is incorrect - ie, they are only numeric (all UK postcodes should start with a alphabet character)

I have done some research and found the grepl command that I've used to generate a TRUE/FALSE vector if the entry is only numeric, 

Data$NewPostCode <- grepl("^.*[0-9]+[A-Za-z]+.*$|.*[A-Za-z]+[0-9]+.*$",Data$PostCode)

however, what I really want to do is where the instance starts with a number to make the postcode blank.

Note, I don't want remove the rows with an incorrect postcode as I will lose information from the other variables. I simply want to remove that postcode

Example data 

Area               Postcode
Birmingham         B1 1AA
Manchester         M1 2BB
Bristol            BS1 1LM
Southampton        1254
London             1290C
Newcastle          N1 3DC

Desired output

Area               Postcode
Birmingham         B1 1AA
Manchester         M1 2BB
Bristol            BS1 1LM
Southampton        
London             
Newcastle          N1 3DC

Upvotes: 0

Views: 44

Answers (1)

Frank
Frank

Reputation: 2416

There are a few ways to go between TRUE/FALSE vectors and the kind of task you want, but I prefer ifelse. A simpler way to generate the type of logical vector you're looking for is

grepl("^[0-9]", Data$PostCode)

which will be TRUE whenever PostCode starts with a number, and FALSE otherwise. You may need to adjust the regex if your needs are more complex.

You can then define a new column which is blank whenever the vector is TRUE and the old value whenever the vector is FALSE, as follows:

Data$NewPostCode <- ifelse(grepl("^[0-9]", Data$PostCode), "", Data$PostCode)

(May I suggest using NA instead of blank?)

Upvotes: 1

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