How do I remove the first occurence of a substring in string?

Question

How can I remove the first occurence of a given substring?

I have:

phrase = "foobarfoo"

and, when I call:

phrase.some_method_i_dont_know_yet ("foo")

I want the phrase to look like barfoo.

I tried with delete and slice but the first removes all the occurrences but the second just returns the slice.

Answer 1

Use sub! to substitute what you are trying to find with ""(nothing), thereby deleting it:

phrase.sub!("foo", "")

The !(bang) at the end makes it permanent. sub is different then gsub in that sub just substitutes the first instance of the string that you are trying to find whereas gsub finds all instances.

Answer 2

Use the String#[] method:

phrase["foo"] = ""

For comparison, in my system this solution is 17% faster than String#sub!

Answer 3

sub will do what you want. gsub is the global version that you're probably already familiar with.