Home Accessibility Courses Twitter The Mouth Facebook Resources Site Map About Us Contact
 
Python and Tcl - public course schedule [here]
Private courses on your site - see [here]
Please ask about maintenance training for Perl, PHP, Lua, etc
 
Is this number between? Does this list include? - Ruby

There's often a requirement in a program to see if one value is between two others, and in most languages you'll write that as as double condition:
  if (n >= 5 && n <= 8) printf("Yesssss!\n");
in C or C++, for example.

Some languages give you further options / methods you can use to test for values between two others - usually they're the object oriented languages where additional operators can be defined as methods. In other words - when the authors of he language ran out of special symbols, they started to use words! Here is a use of the between? method in Ruby:
  if k.between?(5,8)

Another requirement is to see if a value is present in a list / array / collection. And in languages such as C you'll write that as a loop, checking each item of the list in turn and using a break go get out of the loop if and when you find the item you're looking for.

Looking for an item in a list is such a common requirement that many of the object oriented languages have defined methods which let you do the test in a single line, hiding (encapsulating) the loop that's actually still going to be run within the class code. So in Ruby you cab simply write:
  if [2,3,5,6,7].include?(k)

There's a new demonstration of each of these, in the context of a complete program, [here] on our web site. I'm running a private Ruby course this week. Public courses - see [here].
(written 2011-04-18, updated 2011-04-19)

 
Associated topics are indexed as below, or enter http://melksh.am/nnnn for individual articles
R104 - Ruby - Control Structures
  [4674] Alternating valuses / flip-flop / toggle - example in Ruby - (2016-05-17)
  [4504] Where does Ruby load modules from, and how to load from current directory - (2015-06-03)
  [4503] Separating your code for easier testing, understanding and re-use; example in Ruby - (2015-06-02)
  [4402] Finding sum, minimum, maximum and average in Python (and Ruby) - (2015-01-19)
  [4370] Conditionals, loops and methods in Ruby - a primer with simple examples - (2014-12-29)
  [4323] Learning to program - Loop statements such as while - (2014-11-22)
  [4322] Learning to Program - the conditional statement (if) - (2014-11-21)
  [3769] Muttable v immutable and implications - Ruby - (2012-06-20)
  [3620] Finding the total, average, minimum and maximum in a program - (2012-02-22)
  [3619] Ruby v Perl - a comparison example - (2012-02-21)
  [3422] Assigning values to variables within other statements - Ruby - (2011-09-07)
  [3397] Does a for loop evaluate its end condition once, or on every iteration? - (2011-08-18)
  [3254] Multiple inputs, multiple out, ruby functions - (2011-04-19)
  [3200] How a for loop works Java, Perl and other languages - (2011-03-12)
  [3159] Returning multiple values from a function call in various languages - a comparison - (2011-02-06)
  [3158] Ruby training - some fresh examples for string handling applications - (2011-02-05)
  [3156] Splitting data reading code from data processing code - Ruby - (2011-02-04)
  [2975] Why do I need brackets in Ruby ... or Perl, Python, C or Java - (2010-09-29)
  [2892] Alternative loops and conditionals in Ruby and Perl - (2010-07-28)
  [2711] For loop - checked once, or evety time? Ruby v Perl comparison and contrast - (2010-04-07)
  [2619] Passing code to procedures and yield in Ruby - (2010-02-02)
  [2471] A short form of if ... then ... else - (2009-10-23)
  [2287] Learning to program in Ruby - examples of the programming basics - (2009-07-15)
  [1904] Ruby, Perl, Linux, MySQL - some training notes - (2008-11-23)
  [1891] Ruby to access web services - (2008-11-16)
  [1887] Ruby Programming Course - Saturday and Sunday - (2008-11-16)
  [1870] What to do with a huge crop of apples - (2008-11-04)
  [1738] Clean code, jump free (Example in Lua) - (2008-08-06)
  [1696] Saying NOT in Perl, PHP, Python, Lua ... - (2008-07-04)
  [1587] Some Ruby programming examples from our course - (2008-03-21)
  [1582] Ruby, C, Java and more - getting out of loops - (2008-03-19)
  [1220] for loop - how it works (Perl, PHP, Java, C, etc) - (2007-06-06)
  [1163] A better alternative to cutting and pasting code - (2007-04-26)
  [995] Ruby's case - no break - (2006-12-17)
  [985] Equality in Ruby - == eql? and equal? - (2006-12-14)
  [962] Breaking a loop - Ruby and other languages - (2006-12-03)
  [960] 1st, 2nd, 3rd revisited in Ruby - (2006-12-02)

R107 - Collections (Arrays and Hashes) in Ruby
  [4502] Reading and parsing a JSON object in Ruby - (2015-06-01)
  [4499] Significant work - beyond helloworld in Ruby - (2015-05-27)
  [4368] Shuffling a list - Ruby and Python - (2014-12-28)
  [3757] Ruby - a teaching example showing many of the language features in short but useful program - (2012-06-09)
  [3435] Sorta sorting a hash, and what if an exception is NOT thrown - Ruby - (2011-09-12)
  [3257] All possible combinations from a list (Python) or array (Ruby) - (2011-04-23)
  [3255] Process every member of an array, and sort an array - Ruby - (2011-04-21)
  [2976] Creating, extending, traversing and combining Ruby arrays - (2010-09-30)
  [2621] Ruby collections and strings - some new examples - (2010-02-03)
  [2618] What are Ruby Symbols? - (2010-02-02)
  [2606] Sorting arrays and hashes in Ruby - (2010-01-30)
  [2291] Collection objects (array and hash) in Ruby - (2009-07-16)
  [991] Adding a member to a Hash in Ruby - (2006-12-16)


Back to
C++ - unknown array size, unknown object type. Help!
Previous and next
or
Horse's mouth home
Forward to
Multiple inputs, multiple out, ruby functions
Some other Articles
Displaying a directory or file system tree - Linux
Is this number between? Does this list include? - Ruby
C++ - unknown array size, unknown object type. Help!
C++ - objects that are based on other objects, saving coding and adding robustness
C++ - how we teach the language and the concepts behind the language
Events - Spring and Early Summer 2011 in Melksham
What have these pictures in common?
4759 posts, page by page
Link to page ... 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17, 18, 19, 20, 21, 22, 23, 24, 25, 26, 27, 28, 29, 30, 31, 32, 33, 34, 35, 36, 37, 38, 39, 40, 41, 42, 43, 44, 45, 46, 47, 48, 49, 50, 51, 52, 53, 54, 55, 56, 57, 58, 59, 60, 61, 62, 63, 64, 65, 66, 67, 68, 69, 70, 71, 72, 73, 74, 75, 76, 77, 78, 79, 80, 81, 82, 83, 84, 85, 86, 87, 88, 89, 90, 91, 92, 93, 94, 95, 96 at 50 posts per page


This is a page archived from The Horse's Mouth at http://www.wellho.net/horse/ - the diary and writings of Graham Ellis. Every attempt was made to provide current information at the time the page was written, but things do move forward in our business - new software releases, price changes, new techniques. Please check back via our main site for current courses, prices, versions, etc - any mention of a price in "The Horse's Mouth" cannot be taken as an offer to supply at that price.

Link to Ezine home page (for reading).
Link to Blogging home page (to add comments).

You can Add a comment or ranking to this page

© WELL HOUSE CONSULTANTS LTD., 2019: 404 The Spa • Melksham, Wiltshire • United Kingdom • SN12 6QL
PH: 01225 708225 • EMAIL: info@wellho.net • WEB: http://www.wellho.net • SKYPE: wellho

PAGE: http://www.wellho.net/mouth/3253_Is- ... -Ruby.html • PAGE BUILT: Sat May 27 16:49:10 2017 • BUILD SYSTEM: WomanWithCat