Regexp which matches nothing?

ruby-talk
1

How i can construct regexp, which will always matches nothing?

For example:

"xxxxxxx".match /my_special_regexp/
=> should be ALWAYS nil

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2

Joao Silva wrote:

How i can construct regexp, which will always matches nothing?

For example:

"xxxxxxx".match /my_special_regexp/
=> should be ALWAYS nil

How about:

re = /$a^/

···

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3

Why do you want to have a such regex ?

Anyway, it seems that /^$a/ will never match with any string.

"a".match /^$a/
=> nil
"".match /^$a/
=> nil
"a ".match /^$a/
=> nil

···

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4

Joao Silva wrote:

How i can construct regexp, which will always matches nothing?

For example:

"xxxxxxx".match /my_special_regexp/
=> should be ALWAYS nil

not sure, but something that should always be nil .... what about the constant 'nil' :wink:

5

Joao Silva wrote:

How i can construct regexp, which will always matches nothing?

For example:

"xxxxxxx".match /my_special_regexp/
=> should be ALWAYS nil

Just out of curiosity: Why do you use a method call, when you expect a constant?

6

7stud -- wrote:

Joao Silva wrote:

How i can construct regexp, which will always matches nothing?

For example:

"xxxxxxx".match /my_special_regexp/
=> should be ALWAYS nil

How about:

re = /$a^/

I guess that could be made even simpler:

re = /a^/

···

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7

7stud -- wrote:

7stud -- wrote:

Joao Silva wrote:

How i can construct regexp, which will always matches nothing?

For example:

"xxxxxxx".match /my_special_regexp/
=> should be ALWAYS nil

How about:

re = /$a^/

I guess that could be made even simpler:

re = /a^/

..and probably more efficient:

re = /a\A/

···

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