Nuby question - printing substring as non-ASCII

[Thomas Luedeke]

I'm reading in a string of numbers, as follows:

" 1 45.3456 "

How do I write out the first non-whitespace element as a number? Ruby
wants to express as it in ASCII, and the .to_i method doesn't seem to
work on a substring.

Thanks in advance.

TPL

 

[David Vallner]

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I'm reading in a string of numbers, as follows:
=20
" 1 45.3456 "
=20
How do I write out the first non-whitespace element as a number? Ruby =

wants to express as it in ASCII, and the .to_i method doesn't seem to=20
work on a substring.
=20

Doesn't seem to? Code please.

Also, the following works for me:

irb(main):009:0> " 1 45.3456 ".strip.split(/\s+/).map { |i|
i.to_i
}
=3D> [1, 45]

(Of course, to_i coerces to integers, so the body of the map block would
have to be more complicated to get floats too.)


David Vallner


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[Dmitry Buzdin]

Then why not call to_i on a whole string?

" 1 45.3456 ".to_i
" 1 45.3456 ".to_f

It will find the first number and convert it to Fixnum or Float.

Dmitry

 

[Patrick Spence]

I'm reading in a string of numbers, as follows:

" 1 45.3456 "

How do I write out the first non-whitespace element as a number? Ruby
wants to express as it in ASCII, and the .to_i method doesn't seem to
work on a substring.

Thanks in advance.

TPL

irb(main):001:0> " 1 45.3456 ".strip.to_i()
=> 1

 

[Patrick Spence]

Then why not call to_i on a whole string?

" 1 45.3456 ".to_i
" 1 45.3456 ".to_f

It will find the first number and convert it to Fixnum or Float.

Dmitry

You're absolutely right, Dmitry... .strip() is not necessary. But I
tend to be a bit anal-retentive about such things |

 

[Thomas Luedeke]

I'm reading in a string of numbers, as follows:

" 1 45.3456 "

How do I write out the first non-whitespace element as a number? Ruby
wants to express as it in ASCII, and the .to_i method doesn't seem to
work on a substring.

Thanks in advance.

TPL

Thanks. Dumb question, but I'm kinda deep in the throes of the "suck"
stage of learning Ruby. The following also seems to work (at least for
the purposes of reading in and writing formatted output):

irb(main):001:0> string=" 1 45.3456 "
=> " 1 45.3456 "

irb(main):003:0> string.strip
=> "1 45.3456"

irb(main):004:0> string.split[1]
=> "45.3456"

irb(main):005:0> string.split[0]
=> "1"

 

[Wilson Bilkovich]

I'm reading in a string of numbers, as follows:

" 1 45.3456 "

How do I write out the first non-whitespace element as a number? Ruby
wants to express as it in ASCII, and the .to_i method doesn't seem to
work on a substring.

Thanks in advance.

TPL

Thanks. Dumb question, but I'm kinda deep in the throes of the "suck"
stage of learning Ruby. The following also seems to work (at least for
the purposes of reading in and writing formatted output):

irb(main):001:0> string=" 1 45.3456 "
=> " 1 45.3456 "

irb(main):003:0> string.strip
=> "1 45.3456"

irb(main):004:0> string.split[1]
=> "45.3456"

irb(main):005:0> string.split[0]
=> "1"

Here is one way:
irb(main):001:0> string = " 1 45.3456 "
=> " 1 45.3456 "
irb(main):002:0> substrings = string.scan /[^\s]+/
=> ["1", "45.3456"]
irb(main):003:0> substrings.first.to_i
=> 1

The second line of code is saying: Scan the string, and return an
Array of strings that were made up of one or more non-whitespace
characters.

substrings.first is the same as substrings[0]

 

[dblack]

Hi --

I'm reading in a string of numbers, as follows:

" 1 45.3456 "

How do I write out the first non-whitespace element as a number? Ruby
wants to express as it in ASCII, and the .to_i method doesn't seem to
work on a substring.

Thanks in advance.

TPL

Thanks. Dumb question, but I'm kinda deep in the throes of the "suck"
stage of learning Ruby. The following also seems to work (at least for
the purposes of reading in and writing formatted output):

irb(main):001:0> string=" 1 45.3456 "
=> " 1 45.3456 "

irb(main):003:0> string.strip
=> "1 45.3456"

irb(main):004:0> string.split[1]
=> "45.3456"

irb(main):005:0> string.split[0]
=> "1"

Here is one way:
irb(main):001:0> string = " 1 45.3456 "
=> " 1 45.3456 "
irb(main):002:0> substrings = string.scan /[^\s]+/
=> ["1", "45.3456"]
irb(main):003:0> substrings.first.to_i
=> 1

The second line of code is saying: Scan the string, and return an
Array of strings that were made up of one or more non-whitespace
characters.

substrings.first is the same as substrings[0]

Another possibility:


irb(main):001:0> require 'scanf'
=> true
irb(main):002:0> string = " 1 45.3456 "
=> " 1 45.3456 "
irb(main):003:0> string.scanf("%d")
=> [1]

You have to get it out of the array, but you don't have to convert it
(it's already an integer).


David

--
David A. Black | (e-mail address removed)
Author of "Ruby for Rails" [1] | Ruby/Rails training & consultancy [3]
DABlog (DAB's Weblog) [2] | Co-director, Ruby Central, Inc. [4]
[1] http://www.manning.com/black | [3] http://www.rubypowerandlight.com
[2] http://dablog.rubypal.com | [4] http://www.rubycentral.org

 

[Bernard Kenik]

----- Original Message -----
From: "Patrick Spence" <[email protected]>
To: "ruby-talk ML" <[email protected]>
Sent: Friday, November 17, 2006 9:45 AM
Subject: Re: Nuby question - printing substring as non-ASCII

irb(main):001:0> " 1 45.3456 ".strip.to_i()
=> 1

no need to strip
" 1 45.3456".to_i
=> 1