For 2023 - we are now fully retired from IT training. We have made many, many friends over 25 years of teaching about Python, Tcl, Perl, PHP, Lua, Java, C and C++ - and MySQL, Linux and Solaris/SunOS too. Our training notes are now very much out of date, but due to upward compatability most of our examples remain operational and even relevant ad you are welcome to make us if them "as seen" and at your own risk.
Lisa and I (Graham) now live in what was our training centre in Melksham - happy to meet with former delegates here - but do check ahead before coming round. We are far from inactive - rather, enjoying the times that we are retired but still healthy enough in mind and body to be active!
I am also active in many other area and still look after a lot of web sites - you can find an index ((here)) |
Exclamation marks and question marks on ruby method names
In ruby, you'll find some function/method names that are just a series of letters (a rather conventional sort of name for a function or a variable), and others that have a ! or ? on the end. What's the significance of these?
• A function with a ! on the end usually alters the incoming object rather than returning a new object
• A function with a ? on the end usually return a true or false value so would be used in a conditional
• A function with neither a ? nor a ! usually returns a new object.
Here's an example with chop ...
This will not alter stuff, but will return you a result object in less:
less = stuff.chop
whereas this will alter the stuff object:
stuff.chop!
There's a further example [here] - including sample output (written 2010-07-28, updated 2010-07-30)
Associated topics are indexed as below, or enter http://melksh.am/nnnn for individual articles R106 - Input and Output in Ruby [1587] Some Ruby programming examples from our course - (2008-03-21) [1887] Ruby Programming Course - Saturday and Sunday - (2008-11-16) [2290] Opening and reading files - the ruby fundamentals - (2009-07-16) [2614] Neatly formatting results into a table - (2010-02-01) [2621] Ruby collections and strings - some new examples - (2010-02-03) [2974] Formatting your output - options available in Ruby - (2010-09-29) [3429] Searching through all the files in or below a directory - Ruby, Tcl, Perl - (2011-09-09) [4499] Significant work - beyond helloworld in Ruby - (2015-05-27) [4678] Expect with Ruby - a training example to get you started - (2016-05-18)
Some other Articles
The Land of the Black LabradorLAMP - Linux, Apache, MySQL, PHP - install, configure, administerGlobal Computer Maintenance DepartmentSorting people by their namesExclamation marks and question marks on ruby method namesAlternative loops and conditionals in Ruby and PerlWiltshire Council ask how they can help businessesDates and times in PythonShould Python classes each be in their own file?Recent Pictures
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