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up vote 2 down vote favorite

I want to store some values for each string element in Lua array. 

-- Emulating different Browsers
local user_agent = {
"Mozilla/5.0 (Windows NT 6.1; WOW64) AppleWebKit/537.1 (KHTML, like Gecko) Chrome/22.0.1207.1 Safari/537.1",         
"Mozilla/5.0 (Windows NT 6.2; WOW64) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/29.0.1547.2 Safari/537.36",          
"Mozilla/5.0 (Windows NT 6.2) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/28.0.1467.0 Safari/537.36",                   
"Mozilla/5.0 (Windows NT 6.1; rv:22.0) Gecko/20130405 Firefox/22.0",                                                                                  
"Mozilla/5.0 (X11; Linux i686; rv:21.0) Gecko/20100101 Firefox/21.0",                                                               
"Mozilla/5.0 (compatible; MSIE 9.0; Windows NT 6.1; Trident/5.0; FunWebProducts)",                                                          
"Mozilla/5.0 (compatible; MSIE 8.0; Windows NT 6.0; Trident/4.0; InfoPath.1; SV1; .NET CLR 3.8.36217; WOW64; en-US)",               
"Mozilla/5.0 (iPad; CPU OS 6_0 like Mac OS X) AppleWebKit/536.26 (KHTML, like Gecko) Version/6.0 Mobile/10A5355d Safari/8536.25"  
}

-- Number of connections per host and total connections for each browser/user_agent
 user_agent[1].max_conn_perhost , user_agent[1].max_conn_total = 6, 17
 user_agent[2].max_conn_perhost , user_agent[2].max_conn_total = 6, 10
 user_agent[3].max_conn_perhost , user_agent[3].max_conn_total = 6, 10
 user_agent[4].max_conn_perhost , user_agent[4].max_conn_total = 6, 16
 user_agent[5].max_conn_perhost , user_agent[5].max_conn_total = 6, 16
 user_agent[6].max_conn_perhost , user_agent[6].max_conn_total = 6, 35
 user_agent[7].max_conn_perhost , user_agent[7].max_conn_total = 6, 35
 user_agent[8].max_conn_perhost , user_agent[8].max_conn_total = 6, 16

This is throwing error:

attempt to index field '?' (a string value)

I have noticed in some examples that, if I haven't initialized the string array, then it will work. Can anyone please suggest any easier solution to achieve this or rectify the issue.

share|improve this question

2 Answers 2

up vote 4 down vote accepted

From what you've posted, you have a string array and want to index its elements; this code has no chance of working whatsoever:

t = { "foo", "bar" }

-- t[1] is "foo"
-- t[1].xyz is the same as t[1]["xyz"], which evaluates to "foo"["xyz"], which is probably not what you want

What you need is an array of "objects":

t = { {"foo"}, {"bar"} }

t[1].xyz = 5 -- works

However, "foo" will be under index 1, so you probably will want to assign a name for it

t = { {name="foo"}, {name="bar"} }
share|improve this answer
    
Thanks a lot for explaining the issue and solution! –  Kumar Vikramjeet Jul 9 '13 at 5:12
up vote 2 down vote

Insert these lines after declaring user_agent, but before assigning to max_conn_perhost and max_conn_total: 

for i, name in ipairs(user_agent) do
    user_agent[i] = {name = name}
end
share|improve this answer
    
Thanks, for this brief solution! Can you please explain what the second line is achieving? Is it typecasting elements of array into objects? –  Kumar Vikramjeet Jul 9 '13 at 5:13
    
@KumarVikramjeet - It is replacing array elements (strings) with objects containing these strings. –  Egor Skriptunoff Jul 9 '13 at 5:47

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