Porting Perl string substitution to Ruby?

Question

I'm trying to figure out how to do string substitutions while in the process of porting a Perl script to Ruby.

Here's the Perl line. I'm trying to figure out Ruby's equivalent:

$historyURL =~ s/COMPONENT_NAME/$componentName/g;

For those of you who may know Ruby, but not Perl, this line basically substitutes the string "COMPONENT_NAME" in the $historyVariable with the value of the $componentName variable.

I'm curious why this question was downvoted, it seems like a perfectly legitimate question to me, one that I wasn't able to resolve by myself looking at Ruby's API (due to my lack of experience with regular expressions in general) — dsw88, Feb 25 '13 at 16:02

score 5 · Accepted Answer · answered Feb 22 '13 at 21:51

5

The equivalent is pretty straight-forward:

history_url.gsub!(/COMPONENT_NAME/, component_name)

The gsub! method replaces all instances of the given pattern with the second argument and stores the result in the original variable as it is an in-place modifier. gsub by comparison returns a modified copy.

answered Feb 22 '13 at 21:51

tadman

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The `=~` operator exists in Ruby but cannot be used to make modifications as in Perl. It's generally not used, though, in favor of using `match` or the various `sub` methods for reasons of clarity. – tadman Feb 25 '13 at 16:21

score 0 · Answer 2 · answered Feb 22 '13 at 22:05

The nice thing about the gsub-method is that it does not need a regex, it works fine with a string (or a variable pointing to a string):

history_url = "some random text COMPONENT_NAME random text COMPONENT_NAME"
component_name = "lemonade"
p history_url.gsub("COMPONENT_NAME", component_name) # no regex
#=> "some random text lemonade random text lemonade"

Porting Perl string substitution to Ruby?

2 Answers2