查找Swift中字符数组的所有大小写的个数

let charArray: [Character] = ["a", "B", "C", "d", "E", "F", "g", "H", "I", "j"]
var charCountDict: [Character: Int] = [:]

for char in charArray {
    if char.isUppercase {
        if let count = charCountDict[char] {
            charCountDict[char] = count + 1
        } else {
            charCountDict[char] = 1
        }
    } else if char.isLowercase {
        if let count = charCountDict[char] {
            charCountDict[char] = count + 1
        } else {
            charCountDict[char] = 1
        }
    }
}

for (char, count) in charCountDict {
    print("\(char): \(count)")
}

B: 1
C: 1
E: 1
F: 1
H: 1
I: 1
a: 1
d: 1
g: 1
j: 1