Split question

Ruby
1

Hi all,

I try to split a line that is separated by ‘tab’ and expect return an
array with all the elements containing empty space. But my code doesn’t
work. Any idea?

Thanks,

Li

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/)
=> ["\t\t\t\t\t\t\t\t"]
irb(main):003:0> s.split(/\t/)
=> []
irb(main):004:0>

2

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.

3

On Wed, Oct 7, 2009 at 4:29 PM, Li Chen [email protected] wrote:

C:\Documents and Settings\chen41\Desktop>irb

Single quotes treat things literally, like you can’t interpolate, and \t
is
treated as two separate characters.

$irb

RUBY_VERSION
=> “1.8.6”

s = ‘\t\t\t\t\t\t\t\t’
=> “\t\t\t\t\t\t\t\t”

s = “\t\t\t\t\t\t\t\t”
=> “\t\t\t\t\t\t\t\t”

s.split /\t/
=> []

‘abc#{2}def’
=> “abc#{2}def”

“abc#{2}def”
=> “abc2def”

4

Ryan D. 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>

5

Li Chen wrote:

Ryan D. 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)
#=> ["", “”, “”, “”]

hth,

Siep

6

Hi –

On Thu, 8 Oct 2009, Siep K. wrote:

the "" is backslashed, meaning it is a literal backslash.
=> []
So

s = “\t\t\t\t”
s.split(“\t”) #all null fields
#=> []
s.split(“\t”,-1)
#=> [“”, “”, “”, “”]

[“”, “”, “”, “”, “”] I think :slight_smile:

David

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