CODEWITHSUNDEEP
lua
Maurdekye
Maurdekye

Reputation: 3697

Lua arithmetic on string variable

I have this small snippet of code here;

for i=1,1000 do
    n=math.floor(math.sin(i/10.0)*40)
    s=''
    for j=1,n do s=s+'-' end
    print(s)
end

But it gives me an error on line 2: "attempt to perform arithmetic on global 's' (a string value)" I don't know why it's doing this, and it's driving me mad.

Upvotes: 1

Views: 1969

Answers (2)

lhf
lhf

Reputation: 72402

A loop of string concatenations is not recommended because it leads to a quadratic copy (not that it matters for small strings). Try string.rep instead.

for i=1,1000 do
    n=math.floor(math.sin(i/10.0)*40)
    print(string.rep('-',n))
end

Upvotes: 1

Yu Hao
Yu Hao

Reputation: 122493

Unlike some other languages, Lua uses .. to concatenate strings, not +, change

s = s + '-'

to

s = s .. '-'

Upvotes: 4

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