What does w array mean

Question

I m looking at the documentation for FileUtils      I m confused by the following line   FileUtils cp  w cgi rb complex rb date rb     usr lib ruby 1 6    What does the  w mean  Can you point me to the documentation

User · Answer

Excerpted from the documentation for Percent Strings at http://ruby-doc.org/core/doc/syntax/literals_rdoc.html#label-Percent+Strings:

Besides %(...) which creates a String, the % may create other types of object. As with strings, an uppercase letter allows interpolation and escaped characters while a lowercase letter disables them.

These are the types of percent strings in ruby:
...
%w: Array of Strings

User · Answer

W and  w allow you to create an Array of strings without using quotes and commas

User · Answer

I was given a bunch of columns from a CSV spreadsheet of full names of users and I needed to keep the formatting  with spaces  The easiest way I found to get them in while using ruby was to do   names      Porter Smith Jimmy Jones Ronald Jackson  split   n     This highlights that     creates a string like  Porter Smith nJimmyJones nRonald Jackson  and to get the array you split the string on the   n    Porter Smith    Jimmy Jones    Ronald Jackson    So to answer the OP s original question too  they could have wrote   cgi  spaeinfilename rb complex rb date rb  split      if there happened to be space when you want the space to exist in the final array output

User · Answer

w foo bar  is a shortcut for   foo    bar    Meaning it s a notation to write an array of strings separated by spaces instead of commas and without quotes around them  You can find a list of ways of writing literals in zenspider s quickref

User · Answer

There is also  s that allows you to create any symbols  for example    s some words            Same as   some words   s other words           Same as   other words   s last example          Same as   last example    Since Ruby 2 0 0 you also have    i  a b c         gt     a   b   c    i  a b c         gt     a   b   c    i  a b c         gt     a   b   c     etc

User · Answer

Though it s an old post  the question keep coming up and the answers don t always seem clear to me  so  here s my thoughts    w and  W are examples of General Delimited Input types  that relate to Arrays  There are other types that include  q   Q   r   x and  i   The difference between the upper and lower case version is that it gives us access to the features of single and double quotes  With single quotes and  lowercase   w  we have no code interpolation    someCode   and a limited range of escape characters that work       n   With double quotes and  uppercase   W we do have access to these features   The delimiter used can be any character  not just the open parenthesis  Play with the examples above to see that in effect   For a full write up with examples of  w and the full list  escape characters and delimiters  have a look at  Ruby -  w vs  W     secrets revealed

User · Answer

I think of  w   as a  word array  - the elements are delimited by spaces and it returns an array of strings   There are other   literals     r   is another way to write a regular expression   q   is another way to write a single-quoted string  and can be multi-line  which is useful   Q   gives a double-quoted string  x   is a shell command  i   gives an array of symbols  Ruby    2 0 0   s   turns foo into a symbol   foo    I don t know any others  but there may be some lurking around in there

User · Answer

Instead of  w   we should use  w    According to Ruby style guide   Prefer  w to the literal array syntax when you need an array of words  non-empty strings without spaces and special characters in them   Apply this rule only to arrays with two or more elements     bad STATES     draft    open    closed      good STATES    w draft open closed    Use the braces that are the most appropriate for the various kinds of percent literals      for array literals  w   i   W   I  as it is aligned with the standard array literals     bad  w one two three   i one two three     good  w one two three   i one two three    For more read here

[ruby] What does %w(array) mean?

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