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234 is the calling code for Nigeria
1 is the calling code for USA
233 is the calling code for Ghana

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val currenciesMutableMap: MutableMap<String, String> = mutableMapOf("Naira" to "Nigeria", "Dollars" to "USA", "Pounds" to "UK")
println("Countries are ${currenciesMutableMap.values}") // Countries are [Nigeria, USA, UK]
println("Currencies are ${currenciesMutableMap.keys}") // Currencies are [Naira, Dollars, Pounds]
currenciesMutableMap.put("Cedi", "Ghana")
currenciesMutableMap.remove("Dollars")

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print(currenciesMutableMap.get("Nigeria")) // will print Naira
print(currenciesMutableMap["Nigeria"]) // will print Naira

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val personsHashMap: java.util.HashMap<Int, String> = hashMapOf(1 to "Chike", 2 to "John", 3 to "Emeka")
personsHashMap.put(4, "Chuka") 
personsHashMap.remove(2)
print(personsHashMap[1]) // will print Chike

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val postalCodesHashMap: java.util.LinkedHashMap<String, String> =
linkedMapOf("NG" to "Nigeria","AU" to "Australia","CA" to "Canada")
postalCodesHashMap.put("NA", "Namibia")
postalCodesHashMap.remove("AU")
postalCodesHashMap.get("CA") // Canada

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val personsSortedMap: java.util.SortedMap<Int, String> = sortedMapOf(2 to "Chike", 1 to "John", 3 to "Emeka")
personsSortedMap.put(7, "Adam")
personsSortedMap.remove(3)

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val stringList: List<String> = listOf("in", "the", "club")
print(stringList.last()) // will print "club"
 
// given a predicate
print(stringList.last{ it.length == 3}) // will print "the"
 
val intSet: Set<Int> = setOf(3, 5, 6, 6, 6, 3)
print(intSet.last()) // will print 3

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print(stringList.first()) // will print "in"
print(intSet.first()) // will print 3

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val intList: List<Int> = listOf(1, 3, 4)
print(intList.max()) // will print 4
print(intSet.max()) // will print 6

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print(stringList.drop(2)) // will print "club"