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**squeek.** · 06-22-2013, 09:54 PM

[] and . aren't very distinct in Lua, because tables are so flexible (they are used for what would be both arrays and structs in C++). For example, in Lua, table["key"] is the same as table.key. The only reason to use one over the other is if you use a variable that holds the key.

Code:

-- I know the name of the property
local val1 = table.property

-- The name of the property is stored in a variable
local propertyname = "property"
local val2 = table[ propertyname ]

In C++, there is a major difference, because arrays and structs are distinct. Arrays can only have numerical indexes; array["key"] is invalid. Conversely, structs can not use []. To access any properties of structs or classes, you use struct.propertyname (or -> if using a pointer); struct["propertyname"] is invalid.

classstats is an array of structs, so you index into the array using [] and then access the properties of the struct at that index using .

Another way to think about how to access what you want is evaluate things piece by piece. Things inside a [] will get evaluated first and then the result will be used as the index.

classstats[ classnum ].propertyname = get the property "propertyname" of the struct at index classnum in the array classstats
classstats[ classnum.propertyname ] = get the property "propertyname" of the struct/class classnum (not a struct/class; will generate a compile error), then use that property as the index to get the struct in the array classstats
classstats[ classnum[propertyname] ] = get the variable at the index propertyname of the array classnum (not an array; will generate a compile error), then use that variable as the index to get the struct in the array classstats

06-22-2013, 09:54 PM	#5
squeek. Stuff Do-er Lua Team Wiki Team Fortress Forever Staff Join Date: Mar 2007 Location: Northern California Class/Position: Rallygun Shooter Gametype: Conc tag (you just wait) Affiliations: Mustache Brigade Posts Rated Helpful 352 Times	[] and . aren't very distinct in Lua, because tables are so flexible (they are used for what would be both arrays and structs in C++). For example, in Lua, table["key"] is the same as table.key. The only reason to use one over the other is if you use a variable that holds the key. Code: -- I know the name of the property local val1 = table.property -- The name of the property is stored in a variable local propertyname = "property" local val2 = table[ propertyname ] In C++, there is a major difference, because arrays and structs are distinct. Arrays can only have numerical indexes; array["key"] is invalid. Conversely, structs can not use []. To access any properties of structs or classes, you use struct.propertyname (or -> if using a pointer); struct["propertyname"] is invalid. classstats is an array of structs, so you index into the array using [] and then access the properties of the struct at that index using . Another way to think about how to access what you want is evaluate things piece by piece. Things inside a [] will get evaluated first and then the result will be used as the index. classstats[ classnum ].propertyname = get the property "propertyname" of the struct at index classnum in the array classstats classstats[ classnum.propertyname ] = get the property "propertyname" of the struct/class classnum (not a struct/class; will generate a compile error), then use that property as the index to get the struct in the array classstats classstats[ classnum[propertyname] ] = get the variable at the index propertyname of the array classnum (not an array; will generate a compile error), then use that variable as the index to get the struct in the array classstats __________________ #FF.Pickup ¤ Fortress-Forever pickups My Non-official Maps Released FF_DM_Squeek - FF_2Mesa3_Classic - FF_Siege_Classic Beta FF_Myth - FF_Redlight_Greenlight Sick of the people on the internet, always moanin'. They just moan. - Karl Pilkington Last edited by squeek.; 06-22-2013 at 10:05 PM.