Ruby find and replace around a simple pattern

Question

I have some input text, that could contain some patterns like

bla bla bla ###FOO WORLD### bla bla bla
bla bla bla ###FOO BOB###, ###FOO ALICE###bla bla bla

I want to process this and output

bla bla bla HELLO WORLD bla bla bla
bla bla bla HELLO BOB, HELLO ALICEbla bla bla

This is a bit more than find and replace because I want to preserve the content between the ### markers. I understand this should be easy with a regular expression... But I'm very rusty with regexes beyond anything but simple pattern matching.

What is the best way do do this? Do I need a regular expression object. Or does the string class have methods better suited to this?

Baldrick · Accepted Answer · 2013-06-23 15:51:10Z

4

s = "bla bla bla ###FOO BOB###, ###FOO ALICE###bla bla bla"
s.gsub(/###FOO (.*?)###/, 'HELLO \1')
# => bla bla bla HELLO BOB, HELLO ALICEbla bla bla

The FOO (.*?) captures the text after FOO, and the gsub replaces the matching text with HELLO followed by the capture text.

edited Jun 23, 2013 at 15:51

answered Aug 10, 2012 at 14:06

Baldrick

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Comments

Pritesh Jain · Accepted Answer · 2012-08-10 14:20:55Z

0

@Baldrick is Prefectly correct just another answer using blocks :)

 a.gsub(/###FOO (.*?)###/) do
     "HELLO " + $1
 end

answered Aug 10, 2012 at 14:20

Pritesh Jain

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