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What is the reason behind different results between the following regexp statements:
"abbcccddddeeee"[/z*/] # => ""
And these that return nil:
"some matching content"[/missing/] # => nil
"start end"[/\Aend/] # => nil
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=~ is Ruby's basic pattern-matching operator. When one operand is a regular expression and the other is a string then the regular expression is used as a pattern to match against the string. (This operator is equivalently defined by Regexp and String so the order of String and Regexp do not matter.
A regular expression is a sequence of characters that define a search pattern, mainly for use in pattern matching with strings. Ruby regular expressions i.e. Ruby regex for short, helps us to find particular patterns inside a string. Two uses of ruby regex are Validation and Parsing.
What's happening is that /z*/ will return zero or more occurrences of z.
If you use /z+/, which returns one or more, you'll see it returns nil as expected.
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