How can I fix a for loop that checks dictionary values? - regex

Question

I know it may sound like a newbie question, but i'm having a hard time trying to make a loop work.
I'm using Julia language to create a simple regular expressions that checks if a telephone number is valid and return the estate of the number according to the code area. Here are the details:
1-User enters the phone number;
2-Regex tests if it's a valid number;
3-The area code is parsed and checked if present in the dictionary values. If yes, then it should return the key owning that value. Otherwise a simple message saying that area code doesn't exist should be printed.
The problem is: the loop goes for as long as possible, printing if the value is available or not everytime it checks for it in the dictionary. A break wouldn't help much: as soon as it got the first check, it would simply stop.
Then ofc I noticed I had to take the final print statement out of the loop and even maybe assign a variable to get the value copied, but it still overwrites with the very last "Number doesn't exist" result.
How can I rewrite this code so it works?
regexTel = r"^(\+55)?[\s]?\(?(\d{2})?\)?[\s-]?(9?\d{4}[\s-]?\d{4})$"
areaCode = Dict("City A"=> [68],
"City B"=> [82], [...] (and so on)
print("Type the phone number:\n")
telNum = readline()
validTel = (match(regexTel, telNum))
fnlAreaCd = parse(Int32, validTel[2])
for (cityCode, availbCode) in areaCode
if fnlAreaCd in availbCode
println("Phone number: ", validTel[3], "\n",
"Area code: ", fnlAreaCd, "\n",
"City: ", cityCode)
else
println("Area code doesn't exist")
end
end

Answer 1

Your usage of Dict seems strange to me. I think you should use it the other way around.
I believe that the area codes are unique, then the varaible areaCode would be like this:
areaCode = Dict(68 => "City A", 82 => "City B", ...) # do you need to wrap them in an array?
It'll allow you to write much simplier code:
if haskey(areaCode, fnlAreaCd)
cityCode = areaCode[fnlAreaCd]
println("Phone number: ", validTel[3], "\n",
"Area code: ", fnlAreaCd, "\n",
"City: ", cityCode)
else
println("Area code doesn't exist")
end

Answer 2

The matching city won't necessarily be the first entry in the dictionary, but you have instructed the code to say it doesn't exist any time it finds a non-match! Try this instead of your bare loop:
function lookup_areacode(acode)
code_exists = false
for (cityCode, availbCode) in areaCode
if acode in availbCode
code_exists = true
println("Phone number: ", tel, "\n",
"Area code: ", acode, "\n",
"City: ", cityCode)
end
end
if !code_exists
println("Area code doesn't exist")
end
end
lookup_areacode(fnlAreaCd)
You may want to move the dictionary inside the function for neatness.