I've been training in Lua and Python this week - and the two languages are very diferent, but in many ways they're also much the same. Both languages are slim (ie not bloated with facilities). For example neither supports the
++ operator which those of us who do a lot of coding in Perl, PHP, C and C++ are s familiar with.
One of the other big surprises for newcomers to both Python and Lua is that functions (named blocks of code) are themselves first class variables within the same name space and storage space. On one hand this means that you can't have data stored with the same name as a function (but then you don't want to anyway), but on the other hand this gives you a truely refreshing way of doing lots of dynamic coding which can be really exciting too. (And dangerous - it gives you the tools to do really silly things).
Let me give you an example that shows you the way you can manipulate code:
Defining two functions in Lua:
function footie(some)
return math.floor(some / 11)
end
function boat(more)
return math.floor(more / 9)
end
footie and
boat are regular first class variables, so I can put them into a table (Lua's collection structure - a bit like a list or an array):
games = {footie, boat}
And I can them loop through them, running each of them in turn using a pair of round brackets to say "run this as a function":
for _,play in pairs(games) do
teams = play(staff)
print (teams)
end
Complete source example
[here]. And a complete Python example
[here].
(written 2012-04-13, updated 2012-04-14)
Associated topics are indexed as below, or enter http://melksh.am/nnnn for individual articles
Y105 - Python - Functions, Modules and Packages [96] Variable Scope - (2004-10-22)
[105] Distance Learning - (2004-10-31)
[294] Python generator functions, lambdas, and iterators - (2005-04-28)
[303] Lambdas in Python - (2005-05-06)
[308] Call by name v call by value - (2005-05-11)
[340] Code and code maintainance efficiency - (2005-06-08)
[386] What is a callback? - (2005-07-22)
[418] Difference between import and from in Python - (2005-08-18)
[561] Python's Generator functions - (2006-01-11)
[668] Python - block insets help with documentation - (2006-04-04)
[745] Python modules. The distribution, The Cheese Shop and the Vaults of Parnassus. - (2006-06-05)
[749] Cottage industry or production line data handling methods - (2006-06-07)
[775] Do not duplicate your code - (2006-06-23)
[821] Dynamic functions and names - Python - (2006-08-03)
[900] Python - function v method - (2006-10-20)
[912] Recursion in Python - (2006-11-02)
[913] Python - A list of methods - (2006-11-03)
[949] Sludge off the mountain, and Python and PHP - (2006-11-27)
[959] It's the 1st, not the 1nd 1rd or 1th. - (2006-12-01)
[1134] Function / method parameters with * and ** in Python - (2007-04-04)
[1163] A better alternative to cutting and pasting code - (2007-04-26)
[1202] Returning multiple values from a function (Perl, PHP, Python) - (2007-05-24)
[1464] Python Script - easy examples of lots of basics - (2007-12-08)
[1784] Global - Tcl, PHP, Python - (2008-09-03)
[1790] Sharing variables with functions, but keeping them local too - Python - (2008-09-09)
[1869] Anonymous functions (lambdas) and map in Python - (2008-11-04)
[1870] What to do with a huge crop of apples - (2008-11-04)
[1871] Optional and named parameters in Python - (2008-11-05)
[1879] Dynamic code - Python - (2008-11-11)
[2011] Conversion of OSI grid references to Eastings and Northings - (2009-01-28)
[2439] Multiple returns from a function in Python - (2009-10-06)
[2440] Optional parameters to Python functions - (2009-10-07)
[2481] Sample code with errors in it on our web site - (2009-10-29)
[2506] Good example of recursion in Python - analyse an RSS feed - (2009-11-18)
[2520] Global and Enable - two misused words! - (2009-11-30)
[2718] Python - access to variables in the outer scope - (2010-04-12)
[2766] Optional and named parameters to Python functions/methods - (2010-05-15)
[2878] Program for reliability and efficiency - do not duplicate, but rather share and re-use - (2010-07-19)
[2929] Passing a variable number of parameters in to a function / method - (2010-08-20)
[2994] Python - some common questions answered in code examples - (2010-10-10)
[2998] Using an exception to initialise a static variable in a Python function / method - (2010-10-13)
[3159] Returning multiple values from a function call in various languages - a comparison - (2011-02-06)
[3280] Passing parameters to Python functions - the options you have - (2011-05-07)
[3459] Catching the fishes first? - (2011-09-27)
[3464] Passing optional and named parameters to python methods - (2011-10-04)
[3472] Static variables in functions - and better ways using objects - (2011-10-10)
[3474] Python Packages - groupings of modules. An introduction - (2011-10-11)
[3662] Finding all the unique lines in a file, using Python or Perl - (2012-03-20)
[3766] Python timing - when to use a list, and when to use a generator - (2012-06-16)
[3852] Static variables in Python? - (2012-08-29)
[3885] Default local - a good choice by the author of Python - (2012-10-08)
[3931] Optional positional and named parameters in Python - (2012-11-23)
[3945] vargs in Python - how to call a method with unknown number of parameters - (2012-12-06)
[4029] Exception, Lambda, Generator, Slice, Dict - examples in one Python program - (2013-03-04)
[4161] Python varables - checking existance, and call by name or by value? - (2013-08-27)
[4212] Python functions - an introduction to how they work - (2013-11-16)
[4361] Multiple yields and no loops in a Python generator? - (2014-12-22)
[4407] Python - even named code blocks are objects - (2015-01-28)
[4410] A good example of recursion - a real use in Python - (2015-02-01)
[4441] Reading command line parameters in Python - (2015-02-23)
[4448] What is the difference between a function and a method? - (2015-03-04)
[4645] What are callbacks? Why use them? An example in Python - (2016-02-11)
[4662] Recursion in Python - the classic example - (2016-03-07)
[4719] Nesting decorators - (2016-11-02)
[4722] Embedding more complex code into a named block - (2016-11-04)
[4724] From and Import in Python - where is the module loaded from? - (2016-11-06)
U106 - Lua - Functions. [1685] Short circuit evaluation (lazy operator) in Lua - (2008-06-22)
[1697] Sorting in lua - specifying your own sort routine - (2008-07-05)
[1699] If you are learning Lua, here are some more examples - (2008-07-06)
[1743] First class functions in Lua lead to powerful OO facilities - (2008-08-07)
[1744] Lua examples, Lua Courses - (2008-08-08)
[1847] Lua - IAQ (Infrequently Answered Questions) - (2008-10-18)
[2312] What are closures in Lua? - (2009-07-31)
[2347] Dot, dot, dot in Lua - variable length parameter lists - (2009-08-11)
[2356] Passing multiple results back from a function - Lua, Python, etc - (2009-08-13)
[2455] Lua examples - coroutines, error handling, objects, etc - (2009-10-15)
[2723] Returning multiple values from a function - Lua - (2010-04-15)
[2949] Lua - variable function arguments and select - (2010-09-08)
Some other Articles
Bristol 50? Bristol 25?How to stop forms on other sites submitting to your scriptsEvents in Melksham - read all about them, and tell us about yoursMelksham government and business organisationsFunctions are first class variables in Lua and PythonSpecial __ methods you can use in Lua metatablesWiltshire Business Support ServiceDeeper than Art - An exhibition of the tattoo Canvas - MelkshamBack in Cambridge to give a Lua courseChanges in Lua 5.2 - Garbage Collection