String#starts_with?

Ruby
1

Has anyone run tests to see what the fastest way to do a
String#starts_with?(otherstring) is? I’ll need this in an inner loop,
so it’s worth squeezing out the few drops of extra speed.

martin

2

Martin DeMello wrote:

Has anyone run tests to see what the fastest way to do a
String#starts_with?(otherstring) is? I’ll need this in an inner loop,
so it’s worth squeezing out the few drops of extra speed.

String#index should be the fastest

lopex

3

On 7/9/06, Marcin Miel¿yñski [email protected] wrote:

Martin DeMello wrote:

Has anyone run tests to see what the fastest way to do a
String#starts_with?(otherstring) is? I’ll need this in an inner loop,
so it’s worth squeezing out the few drops of extra speed.

String#index should be the fastest

thanks. any suggestions for #ends_with?

martin

4

Marcin MielżyÅ?ski wrote:

String#index should be the fastest

I’m afraid it isn’t suitable for this case. String#index searches the
whole string when the string doesn’t start with the start, which is very
bad.

Use String#[] or a regular expression:

text = “this is a test”
search = “this”
text[0, search.length] == search #=> true

text =~ /^this/ #=> 0 (true)
text =~ /^test/ #=> nil (false)

Cheers,
Robin S.

5

Martin DeMello wrote:

thanks. any suggestions for #ends_with?

Yes, two examples:

“this is a test” =~ /test$/ #=> 10 (true)

text = “this is a test”
search = “test”
text[text.length - search.length, search.length] == search #=> true