… What is the difference between a function and a method? Returning multiple values from a function - Lua Does it strike you as odd that in many languages, functions can take in as many parameters as you like, but can only return one? How do I set one up? In other words, either you use what's available in Lua, or you write your own function. why this is a syntax error I can not understand. Functions in Lua can return multiple results. Modern IDEs are magic. Parallel but not really parallel. Training, Open Source Programming Languages, Special Tcl, Expect, Tk subjects / courses.

Or use tables as suggested by Egor's comment. r/lua: News and discussion for the Lua programming language. When a variable amount of results are returned by a function, one can store them all in a table, by executing the function inside it: This way, one can iterate over the results table to see what the function returned. Redis Cluster: Find which master holds particular key/slot, ROBLOX Lua Error in script: '=' expected near ', How to Draw Circle, incrementally, to create an animated fill effect (using Corona). Tables as Objects in Lua - a gentle introduction to data driven programming. Making statements based on opinion; back them up with references or personal experience. From Lua 5.3 Reference Manual 3.4 Expressions. Using == for functions only checks if they reference to the same function, which is not what you expected. Weak references in Lua - what are they, and why use them? rev 2020.11.11.37991, Stack Overflow works best with JavaScript enabled, Where developers & technologists share private knowledge with coworkers, Programming & related technical career opportunities, Recruit tech talent & build your employer brand, Reach developers & technologists worldwide, @towi you have to implement element-wise comparison yourself. Coroutines in Lua.

Lua functions can return multiple values, and the language will natively assign them to the variables on the other side of the equal sign. When a function returns multiple values, how can I use each value individually? Both function calls and vararg expressions can result in multiple Can Lua's require function return multiple results? Using == for functions only checks if they reference to the same function, which is not what you expected. I havent integrated into.

How can a chess game with clock take 5 hours?

For your example:... You found a variant of the Multi-dimensional Knapsack Problem, which is known to be NP-complete. How do our tactics help us meet the strategy, for the greater good? 3. Lua - Is it possible to check if 2 functions are equal?

end subroutine foo You can learn more about this example on the training courses listed on this page, You'll find a description of the topic and some You could always return a function from your module and have that return multiple values, like below. Sorting 2D boxes into larger boxes to fill in the most efficient and complete manner, Erlang spawning large amounts of C processes, storyboard.removeScene(“scene name”) is not working. Does learning the same spell from different sources allow it to benefit from bonuses from all sources? Lua - using modules to add your own utilities, Lua - changes to how integers and floats are handled - 5.2 to 5.3, Perl, PHP, Python, Lua, Tcl, C++, Ruby - final public courses for 2015, Function prototype - what they are and why you should use them - C and C++, Passing information into functions in C - by name, by value, Scenario outlines - tables of values to test - in Gherkin / Cucumber. I circumvented this by defining helper functions which I am sure are already in Lua, if I only knew where to look: While this works it is quite cumbersome and it would be so much nicer to have the whole check in one line... but how? the examples they use to ensure that they are suitable for their By using our site, you acknowledge that you have read and understand our Cookie Policy, Privacy Policy, and our Terms of Service. How to deal with a younger coworker who is too reliant on online sources, How to run custom sql commands to database programatically.


The general form of a method definition in Lua programming language is as follows − A method definition in Lua programming language consists of a method header and a method body. Georgia doing "hand recount" of 2020 Presidential Election Ballots.

I am trying to use this code for my own purposes. Since MyClass is just a lookup in the global table (_G), you could mess with its metatable's __index to return a newly-defined MyClass object (which you would later need to fill with the details). Lua functions actually return separate values, instead of a single container. This example comes from our "Functions." Please see the linked article for further explanation. How to iterate through a table in its exact order? Using == for functions only checks if they reference to the same function, which is not what you expected. If a function call is used as a statement (see §3.3.6), then its return list is adjusted to zero elements, thus discarding all returned values.

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2. I still have to read the entire docs, but already found this: There are 16384 hash slots in Redis Cluster, and to compute what is the hash slot of a given key, we simply take the CRC16 of the key modulo 16384. If you're used to a language (like Python) that returns multiple values by storing them in a "tuple" type, that's not how Lua works. Used like this, the list returned by stuff() will be reduced to the first element, because stuff() is not the last expression in that expression list.

on which you'll be given a full set of training notes. Was AGP only ever used for graphics cards? Thanks for contributing an answer to Stack Overflow! This modified text is an extract of the original Stack Overflow Documentation created by following.

The function name and the parameter list together constitute the function signature.

I'm currently writing an extension to package.loaders and I want to know if I need to support such behavior. You could swap the table and stuff() to circumvent this in a simple manner. I have written a test utility function aequals (assert equals) that expects an actual result and an expected result as arguments. Returning multiple values from a function using an array.

To learn more, see our tips on writing great answers. It returns two indices: the index of the character where the pattern match starts and the one where it ends (or nil if it cannot find the pattern). It returns R,G,B values. How important is the gate threshold voltage on a MOSFET, Mystery game from 2000s set on an island with a bell. Returning guests - a sign of a good product. local a, b = (function() return 1,2 end)() print(a,b) => 1 2 That's fine, but when things get a bit more tricky is when the values are not returned in tail call position. String formatting in Lua - string.format as a wrapper for sprintf. Multiple views in a single appication - sharing common parts of the template - Ruby on Rails, What is a metatable?

An example is the string.find function, which locates a pattern in a string. require lua export implemented in static int ll_require (lua_State *L) in loadlib.c file. Lua - Is it possible to check if 2 functions are equal? except the first one or adding a single nil if there are no values. Multiple identical keys in a Python dict - yes, you can!

Who "spent four years refusing to accept the validity of the [2016] election"? The purpose of this Lua function is only to provide a unique name. print(get_two_values()) -- 2 5. local a, b = get_two_values() -- a = 2, b =5. the multiple values will be assigned to multiple vars or can be sent to functions with multiple arguments for example. What does "class classname* funcname(void) "mean in c++?

Does it strike you as odd that in many languages, functions can take in as many parameters as you like, but can only return one? This task is rather difficult, if not impossible at all. How can I handle a PC wanting to be a "twist" villain? How I get the cdata out in c function with variable arguments using luajit?

lua return multiple values . but this gives a syntax error, because stuff returns a tuple, not an array/table. It is possible to create a Lua module which returns multiple results via the require function? Also cacheing in objects and multiple catch clauses example.

How should I visualize the average of two bars in a bar chart? This task is rather difficult, if not impossible at all.

This returns two values, which I know to be width,height.

Encapsulating logic in functions and structs - the C approach to Object Oriented techniques, Extending your bash shell with aliases, functions and extra commands, repeat until in Lua - a one or more rather than a zero or more loop. Past attendees on our training courses are welcome to use individual So for instance, I would like to assign the return values of the getDimensions() function to a new table with keys width and height, respectively. ) Receives zero or more integers. Here are all the parts of a method − 1.

This module and example are covered on the following public courses: Yes. Moving game characters. Why populate object with values as you construct them?

Lazy operators in Lua - what they mean, and examples, Line, block and nested comments - Lua compared to other languages, Embedding Lua to perform tailored code at an interval, Metatables, Metamethods, classes and objects in Lua, Python, PHP, Ruby, C, Lua, etc ... course prices held for the rest of 2014, Python functions - an introduction to how they work. examples in the course of their programming, but must check Dark mornings, dog update, and Python and Lua courses before Christmas, Using Perl to generate multiple reports from a HUGE file, efficiently, December courses - PHP, Python, Perl - and a weekend Lua course, Metaclasses (Python) and Metatables (Lua), Static variables in functions - and better ways using objects, Assigning values to variables within other statements - Ruby, Passing back multiple results in Tcl - upvar and uplevel.

subroutine foo(c, b) character(len=:), allocatable, intent(out) :: c logical, intent(out) :: b c = 'string' b = .false. If an expression is used as the last (or the only)

Return skips other code function f (switch) if not switch then return end print ("Hello") end f () 90's PC game, similar to "Another World" but in 3D, dark, purple, locked inside a prison. Stack Overflow for Teams is a private, secure spot for you and I'm currently writing an extension to package.loaders and I want to know if I need to support such behavior.

This functions always returns 1 as number of returned values on stack. What circumstances could lead to city layout based on hexagons? A number of the string functions work like this,for instance, string.find will return the start index and end index of the match, plus any captures. I tried to fix this using the array-constructor, which supposed to make a tuple into an array/table. If you can make the Lua code — or more accurately, its underlying native code — cooperate with the Erlang VM, you have a few choices. I want to assign them to a new table, as an array. Returns a string with length equal to the number of arguments, in which each character has the internal numerical code equal to its corresponding argument. Python or Lua - which should I use / learn? values. Why is "hand recount" better than "computer rescan"? Lua, Learning to Program in Lua - public / open training course / class, Splitting a record into individual data values in C, Returning extra results from a function in C, Refresh and Revision training class days - Perl / PHP / Python / Lua / Ruby / Tcl / C / C++, Special __ methods you can use in Lua metatables, Binary / bitwise operations in Lua with the standard bit32 library. This can be a surprise in some cases, for example: This happens because string.gsub returns 2 values: the given string, with occurrences of the pattern replaced, and the total number of matches that occurred. This web site is written and maintained by, This is a sample program, class demonstration or answer from a.