Swift--Dictionary

Swift--Dictionary

1. Create an empty dictionary

Way One:

var dic1 = [int:string] () the type of the//key is Int and the type of value is String

Way two:

var dic2 = dictionary<sting,int> ()//key is of type Sting

2. Create a dictionary with literal amounts

var dic3:dictionary<int,string> = [1: "A", 2: "B", 3: "C"]

3. Get the number of elements

Print (Dic3.count)

4. Is the empty

Print (Dic3.isempty)

5. Get the value

Print (dic3[2]!) ! Convert optional Types

6. Change the value

DIC3[2] = "ABC"

7. Delete a value

Way One:

DIC3[2] = nil//Because the element in the dictionary is an optional type, it can be nil directly

Way two:

Dic.removevalueforkey (2)

8. Traversing a dictionary

Way One:

For KV in dic3{

Print (KV)//Tuple format:(1, "a")

}

Way two:

for (Mkey,mvalue) in dic3{

Print (Mkey,mvalue)

}

9. Ordered output of the dictionary (small-to-large)

For key in Dic3.keys.sort () {

Print (Key,dic3[key])

}

Swift--Dictionary