How to remove empty space in a string and others

Ruby
1

Hi all,

  1. I read lines from a file and put them into one string. There are many
    empty sapces within the string. Which method is used to remove the
    spaces? I try gsub!("\s",’’) but it doesn’t work. Any help will be
    appreciated.

  2. I read each line from a file and split each of them into several
    fields/segments. Then I need to populate an array with one field only
    from each line. How do I do that? I know do these in Perl but have no
    idea using Ruby.

  3. How do I search help or some methods/predifined variables from ruby
    command prompt? Is it possible to do that? Right now the only thing I
    can do is to open the folder containing the manual and read them in IE
    browser. Is this the Ruby way?

Thanks in advance,

Li

2

On Oct 9, 2006, at 9:13 AM, Li Chen wrote:

Hi all,

  1. I read lines from a file and put them into one string. There are
    many
    empty sapces within the string. Which method is used to remove the
    spaces? I try gsub!(“\s”,‘’) but it doesn’t work. Any help will be
    appreciated.

Try gsub(/\s/, ‘’)

  1. I read each line from a file and split each of them into several
    fields/segments. Then I need to populate an array with one field only
    from each line. How do I do that? I know do these in Perl but have no
    idea using Ruby.

Would need more information about your code to answer this.

  1. How do I search help or some methods/predifined variables from ruby
    command prompt? Is it possible to do that? Right now the only thing I
    can do is to open the folder containing the manual and read them
    in IE
    browser. Is this the Ruby way?

There’s nothing wrong with your way, but there are many other ways to
get help while coding. Here are two you might consider:

  1. visit and download from

    http://ruby.cenophobie.com/rubycheat.php

The Ruby Cheatsheet is especially good for looking up predefined
variables.

  1. Open another terminal window and use ri to get help on classes and
    methods. For example:

    ri gsub

Regards, Morton

3
  1. I read each line from a file and split each of them into several
    fields/segments. Then I need to populate an array with one field only
    from each line. How do I do that? I know do these in Perl but have no
    idea using Ruby.

Would need more information about your code to answer this.

I have a file called array.txt with many lines and each line is a record
containing different fields separated by \t. What I like to do is read
the file line by line, split each line into elements, and push the
element [1] from each line into a new array.

array.txt

A B C
1 2 3
X Y Z
…

expected output in new array
[B,2,Y,…]

Thanks,

Li

4

output = []
File.open( “array.txt” ) { |file| file.readlines { |curr_line| output
<< curr_line.split( /\t/ )[1] } }

just to show the result

require ‘pp’
pp output

I need more information about file reading. Which chapter in the
Programming Ruby talks about this stuff?

Thanks,

Li

5

Li Chen wrote:

the file line by line, split each line into elements, and push the
[B,2,Y,…]

Thanks,

Li

output = []
File.open( “array.txt” ) { |file| file.readlines { |curr_line| output
<< curr_line.split( /\t/ )[1] } }

just to show the result

require ‘pp’
pp output