I want to make a program that chooses a random monster from a list, give the user a list of usable weapons, and allows them to choose which weapon to use. I want to use external files to store data for the weapons instead of adding the tables in the Lua file itself. I have tried using Lua files to store the data as a table.
I have a file called sword.lua in the same folder as the program I want to access it's information. It contains
sword = {'sword', '10', '1', '100'}
I am trying to access the information using
wep = io.open("sword.lua", "r")
print(wep:read("*a"))
print(wep[1])
The first print returns all of the text in the file which is
"sword = {'sword', '10', '1', '100'}"
and the second is supposed to return the first item in the table. Every time I do this, I get a nil value from the second print. The file is being read, as indicated by the first print listing the text, but how do I make it read the file as a table that I can use in my program.
To load a table from a file use the require function. For example, save
return { 'sword', '10', '1', '100' }
as sword.lua. Why do I just use return instead of assigning to a variable? It's because that is much more flexible. If I assign the table to the variable sword inside the file, I'm sort of locked into that naming convention and furthermore I pollute the global namespace, making name collisions more likely.
With the above solution I can also assign to a local variable, like so
local sword = require("sword")
print(table.concat(sword,", "))
Another advantage is that calls to require are cached, i.e. even if you require("sword") many times, you only pay the cost for loading once. But keep in mind that because of caching you always get a handle to the same table, i.e. if you alter the table returned from require("sword"), these modifications will be shared by all instances.
Example on Wandbox
Related
I am working on a game in Roblox and need a little help finding objects with attribute values. It is a tycoon for anyone here familiar with Roblox. I would like to know how you can find all instances with say the attribute Unlock_ID: 1, and then when you press the corresponding button, it will unlock it, or make it show up on the screen. I know how to make the objects unlock, I just don't know how to get all the objects with that attribute.
To put it more simply:
I want to find all the objects/instances inside a section with a specific attribute and a specific value and put them inside a table.
I hope this makes sense.
You can use a for i,v in ipairs loops along with the Folder:GetChildren() as your iteration directory. Then you can insert the instance (using table.insert(table,element) into a table if their part:GetAttribute('Unlock_ID') is equal to 1. To achieve this, simply do the following:
local partsWithAttribute = {}
local folder = workspace.Folder -- change this to whatever path you want to iterate through
for i,part in ipairs(folder:GetChildren()) do
if part:GetAttribute('Unlock_ID') == 1 then
table.insert(partsWithAttribute,part)
end
end
I need some architectural advice. I'm more into java, but trying to get up to speed with Ruby-on-rails. In the app I am building I need a convenient place to store some dictionary values that will be later used in various places of the application. These will be usually key value pairs - e.g. list of values to be used in select list.
The main objective is to keep this logic in one place of the application.
I am considering following options:
Store values in the database - i'm kind of reluctant from that, as values won't change very often.
Put all of the values in one class. In JAVA I'd have some static properties in one class holding this values (e.g. call Utils.getStates() will return list of states). How to do it ruby way?
Have some .yml file with values - read from the values. How to do it? I guess I have to parse the file in the initializer, but is there any tutorial how to do it?
Precise example? Let's say that have a model that have a field called "Type". Type can be: ['Type A', 'Type B', 'Type C'...]. And of course, for each type I want to have key and value.
I'd appreciate some suggestions about how you solve this problem in your apps.
Thanks,
Maciek
How often does the list change? Is it acceptable to have developers involved each time a value changes (updating code, re-deploying the app)? If the answer is no then store the values in a database.
Is the list of values reuseable? Then a gem or a yaml file with an initializer might be a good choice.
Is it just a small list and does not change often? Then you might want to consider a constant.
I think in Rails any data that would change at runtime and needs to be persisted, would normally be stored in the database. I think that would be the "rails way". You could save the data to yaml or json file, but that would not follow the normal flow of the MVC pattern that is so common in rails
Dealing with some legacy code we came across a rather annoying situation. We are looping through a query with the <cfoutput query="x"> tag. That query has a column named 'url'. Within that loop we need to check if a key exists within the url scope. Since CF puts a priority on what's in the query over general page scopes I can't use a structKeyExists(url,"key") since as far as CF is concerned at this point, url is a string with the value from the current row of the query.
How can I break out of the query scope and inspect what's in my url?
As a temporary we are using isDefined("url.key"), but I would still like to know if there is a way to break out of the query scope.
Also can't really change the column, or even the column name in the query without a few hours of work tracking down an changing all references to it, so we're going to avoid that if at all possible.
EDIT:
There seems to be some confusion as to how this code is set up, and why the simple solutions don't apply. It would be hard for me to give a thorough example but I will try to clarify the situation.
There are many pages that would count as 'pageA' for the following example. Enough that changing how things work would require a change in scope and investment in time that's just not going to happen in the time allotted.
PageA runs a query with one of the columns being named url, then starts an output loop via cfoutput, inside that loop PageB is included. One PageA may have different variables in the URL scope than another PageA, actually they are the same, but may be named differently(varID=x in one case vid=x in another). Inside of PageB I need to use the value from that url scope, so I want to run through the different possible names (if key 'varID' exists in url, use it, otherwise use 'vid').
This is why I want to "punch through" the query scope to get the url structure, and not the url column from the query. Any other method seems to require modifying the many PageAs.
So the question is not how to solve this problem specifically, as there are many ways to do it, I would just really like to avoid them as they all add a lot of time in implementation and testing. The question remains, is there a way to access the url scope as a variable if url exists as a query column and you are in the query scope.
I thought it might work to create a function that returned the url scope, but upon testing it, even with a local-scoped query (which prevents the function using the query itself) the use of url inside the function is still corrupted:
<cffunction name="getUrlScope"><cfreturn Url /></cffunction>
...
<cfoutput query="x">
<cfif StructKeyExists( getUrlScope() , 'key' )>
<!--- still fails :( --->
There is however an undocumented (meaning unsupported and liable to change) option. If you dump getPageContext() you will see a bunch of functions that do interesting things, including dealing with scopes.
You can use getPageContext().SymTab_findBuiltinScope('URL') to get at the URL scope.
You can also use getPageContext().getCfScopes() to get an array of scopes. I'm not sure if the order is guaranteed fixed but it seems to be [cgi,?,url,form,cookie,?] checking on both CF10 and cflive (CF9), so possibly is.
(In CF8 there was the method getBuiltinScopes, which returned a struct instead of an array - this no longer appears to exist, reinforcing the whole unsupported and changeable nature of these methods.)
On Railo those don't work, but there is getPageContext.UrlScope() and similarly-named functions for the other scopes.
One solution would be to assign the url struct to a new variable outside of the cfoutput tag and then reference that variable instead of url. Example:
<cfset urlScope = url>
<cfoutput query="x">
<cfset keyExists = structKeyExists(urlScope, "key")>
</cfoutput>
My solution for this is always to alias the url column in the query as int
SELECT URL as qURL FROM myTable ...
IF you don't have access to the query (it's a stored precedure or used elswhere etc) you can always use query of a query to reselect it with your alias.
I don't care for the idea of creating a separate reference to URL outside the output - but that would also work. I just want to KNOW what is user input (i.e. comes from the URL or FORM) and what is generated internally (i.e. comes from a query).
Couldn't you move structKeyExists(url,"key") outside of the cfoutput block, and store that into a variable? Or do a structAppend to copy the url struct into another struct named something else?
Another approach is to replace your cfoutput block with a cfloop block.
<cfloop from="1' to = "#YourQuery.recordcount#" index = "idx">
<cfif StructKeyExits(url,"key")>
<cfoutput>
#url.key# is not the same as #YourQuery.url[idx]#
which can also be referenced like this #YourQuery["url"][idx]
etc
I recently wrote a mailing platform for one of our employees to use. The system runs great, scales great, and is fun to use. However, it is currently inoperable due to a bug that I can't figure out how to fix (fairly inexperienced developer).
The process goes something like this...
Upload a CSV file to a specific FTP directory.
Go to the import_mailing_list page.
Choose a CSV file within the FTP directory.
Name and describe what the list contains.
Associate file headings with database columns.
Then, the back-end loops over each line of the file, associating the values with a heading, and importing these values into a database.
This all works wonderfully, except in a specific case, when a raw CSV is not correctly formatted. For example...
fname, lname, email
Bob, Schlumberger, bob#bob.com
Bobbette, Schlumberger
Another, Record, goeshere#email.com
As you can see, there is a missing comma on line two. This would cause an error when attempting to pull "valArray[3]" (or valArray[2], in the case of every language but mine).
I am looking for the most efficient solution to keep this error from happening. Perhaps I should check the array length, and compare it to the index we're going to attempt to pull, before pulling it. But to do this for each and every value seems inefficient. Anybody have another idea?
Our stack is ColdFusion 8/9 and MySQL 5.1. This is why I refer to the array index as [3].
There's ArrayIsDefined(array, elementIndex), or ArrayLen(array)
seems inefficient?
You gotta code what you need to code, forget about inefficiency. Get it right before you get it fast (when needed).
I suppose if you are looking for another way of doing this (instead of checking the array length each time, although that really doesn't sound that bad to me), you could wrap each line insert attempt in a try/catch block. If it fails, then stuff the failed row in a buffer (including the line number and error message) that you could then display to the user after the batch has completed, so they could see each of the failed lines and why they failed. This has the advantages of 1) not having to explicitly check the array length each time and 2) catching other errors that you might not have anticipated beforehand (maybe a value is too long for your field, for example).
A Cobol program with file-control like so:
SELECT D-FLAT-FILE ASSIGN TO DFLAT-FILE
ORGANIZATION IS INDEXED
ACCESS MODE IS SEQUENTIAL
FILE STATUS IS RECORD-STAT
RECORD KEY IS D_KEY OF D-FLAT-FILE DESCENDING WITH DUPLICATES.
SELECT C-MAST-FILE ASSIGN TO CMAST-FILE
ORGANIZATION IS INDEXED
ACCESS MODE IS DYNAMIC
FILE STATUS IS RECORD-STAT
RECORD KEY IS C_KEY OF C-MAST-FILE.
reads a record from the first flat file like so:
PROCESSING.
READ D-FLAT-FILE NEXT RECORD
AT END ....END READ.
and reads a record on the second DYNAMIC file like so:
READ C-MAST-FILE RECORD
INVALID KEY
GO TO PROCESSING.
All works well except for 1 case. If the 1st record from the 1st flat file does not match any records on the 2nd dynamic file, the program goes into an infinite loop instead of doing GO TO PROCESSING. I checked the manuals, all as per manual (it is the VAX Cobol). What am I missing?
Best practice is to use a different FILE STATUS variable for each file. In your case you haven't shown us enough context to see the problem. But if you are in a loop looking at RECORD-STAT, then it is possible that the failed read from C-MAST-FILE is giving you grief.