CODEWITHSUNDEEP
regexr
Hell_77
Hell_77

Reputation: 69

Character matching in R

In R, I have table:

Field1

&&hello
&hi
Hello
Hi

How to remove everything that starts with "&"?

gsub("&", "", A$Field1)

will only remove "&" but not "&&hello" or "&hi" as I need it. I tried "&*" or "&+" but it’s still not working.

Upvotes: 0

Views: 522

Answers (2)

Jim
Jim

Reputation: 172

I'm not 100% sure what you're asking, but if you want to remove the lines with an ampersand in them, you could use:

a <- c("&hi", "&&hello", "Hello", "Hi")

b <- a[-grep("&", a)]

> b
[1] "Hello" "Hi"

Cheers, Jim

Upvotes: 0

flodel
flodel

Reputation: 89057

Using gsub, you need to match the whole string:

gsub("^&.*", "", A$Field1)

but I find a combination of ifelse and grepl a little more elegant:

ifelse(grepl("^&", A$Field1), "", A$Field1)

If the goal is to replace it in your dataframe, then you can reassign:

A$Field1 <- ifelse(grepl("^&", A$Field1), "", A$Field1)

Upvotes: 1

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