From: "David A. Black" <dblack@...>
Date: 2009-10-08T07:02:38+09:00
Subject: Re: split question

Hi --

On Thu, 8 Oct 2009, Siep Korteling wrote:

> Li Chen wrote:
>> Ryan Davis wrote:
>>> On Oct 7, 2009, at 14:29 , Li Chen wrote:
>>>
>>>>
>>>> C:\Documents and Settings\chen41\Desktop>irb
>>>> irb(main):001:0> s='\t\t\t\t\t\t\t\t'
>>>> => "\\t\\t\\t\\t\\t\\t\\t\\t"
>>>
>>> These aren't tabs. They're "\" followed by "t", you can tell because
>>> the "\" is backslashed, meaning it is a literal backslash.
>>>
>>> Use double quotes instead.
>>
>> Here is what I get using double quotes. I get an empty array only.
>>
>>
>> C:\Documents and Settings\chen41\Desktop>irb
>> irb(main):001:0> s="\t\t\t\t\t\t\t\t"
>> => "\t\t\t\t\t\t\t\t"
>> irb(main):002:0> s.split(/\t/)
>> => []
>> irb(main):003:0>
>
> str.split takes two parameters: the pattern and optionally the "limit"
>> From the docs:
> If the limit parameter is omitted, trailing null fields are suppressed.
> If limit is a positive number, at most that number of fields will be
> returned (if limit is 1, the entire string is returned as the only entry
> in an array). If negative, there is no limit to the number of fields
> returned, and trailing null fields are not suppressed.
>
> So
>
> s = "\t\t\t\t"
> s.split("\t")  #all null fields
> #=> []
> s.split("\t",-1)
> #=> ["", "", "", ""]

["", "", "", "", ""] I think :-)


David

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