Answer:

non-Pangrams: 819,

Pangrams: 181, of which 49 are perfect Pangrams

Swift Code:

import Foundation

func loadStringArray(from url: URL, decoder: JSONDecoder = JSONDecoder()) -> [String] {
    do {
        let data = try Data(contentsOf: url, options: [.mappedIfSafe])
        return try decoder.decode([String].self, from: data)
    }
    catch  {
        print(error)
    }
    return []
}

if let fileName = Array(CommandLine.arguments.dropFirst()).first {
    let allStrings = loadStringArray(from: URL(filePath: fileName))
        
    let converted  = allStrings.map { str in str.lowercased().filter { $0 >= "a" && $0 <= "z" } }.map {str in
        var ret = Array<Int>(repeating: 0, count: 26)
            str.forEach {
                if let i = $0.asciiValue, i >= 97, i <= 122 { ret[Int(i-97)] +=  1 }
            }
        return ret
    }

    let pangram = converted.filter { conv in conv.allSatisfy { $0 >= 1 }}
    
    let perfectpangram = converted.filter { $0.allSatisfy { $0 == 1 }}
    
    print("non-Pangrams: \(converted.count - pangram.count),\nPangrams: \(pangram.count), of which \(perfectpangram.count) are perfect Pangrams")
}

Answer:

non-Pangrams: 819,

Pangrams: 181, of which 49 are perfect Pangrams (and 132 non-perfect)

Swift Code:

import Foundation

func loadStringArray(from url: URL, decoder: JSONDecoder = JSONDecoder()) -> [String] {
    do {
        let data = try Data(contentsOf: url, options: [.mappedIfSafe])
        return try decoder.decode([String].self, from: data)
    }
    catch  {
        print(error)
    }
    return []
}

if let fileName = Array(CommandLine.arguments.dropFirst()).first {
    let allStrings = loadStringArray(from: URL(filePath: fileName))
        
    let converted  = allStrings.map { str in str.lowercased().filter { $0 >= "a" && $0 <= "z" } }.map {str in
        var ret = Array<Int>(repeating: 0, count: 26)
            str.forEach {
                if let i = $0.asciiValue, i >= 97, i <= 122 { ret[Int(i-97)] +=  1 }
            }
        return ret
    }

    let pangram = converted.filter { conv in conv.allSatisfy { $0 >= 1 }}
    
    let perfectpangram = converted.filter { $0.allSatisfy { $0 == 1 }}
    
    print("non-Pangrams: \(converted.count - pangram.count),\nPangrams: \(pangram.count), of which \(perfectpangram.count) are perfect Pangrams")
}