C# Container Comprehensive Exercise
Question 1: Basic Dictionary Exercises
1. Create a dictionary dictA, where Key is a string and Value is an integer.
2. Add a total of 26 keys from "a" to "z" to this dictionary, and the values are random numbers from 1 to 10.
3. For the dictionary dictA, delete all key-value pairs whose value is even.
4. Create the same dictionary dictB again, and also delete the keys with even numbers.
5. The two dictionaries are then merged into a new dictionary. For the part with the same Key, the value of dictA shall prevail
using System;
using System.Collections.Generic;
using System.Text;
namespace ConsoleApp9
{
class Program
{
static void InitDic(Dictionary<char, int> dic)
{
Random r = new Random();
string a = $"a";
int asc = Asc(a);
for (int i = 0; i < 26; i++)
{
dic.Add((char)asc, r.Next(1, 10));
asc++;
}
}
public static int Asc(string s)
{
if(s.Length == 1)
{
ASCIIEncoding a = new ASCIIEncoding();
int b = (int)a.GetBytes(s)[0];
return b;
}
else
{
throw new Exception("String is not vaild");
}
}
public static char Cha(string s)
{
int a = int.Parse(s);
if(a >=0 && a <= 255)
{
char c = (char)a;
return c;
}
else
{
throw new Exception("String is not vaild");
}
}
static void PrintDic(Dictionary<char,int> dict)
{
foreach(var pair in dict)
{
Console.WriteLine(pair.Key + " " + pair.Value);
}
}
static void Deleven(Dictionary<char,int> dict)
{
List<char> L = new List<char>();
foreach(var pair in dict)
{
if (pair.Value % 2 == 0)
{
L.Add(pair.Key);
}
}
foreach(var key in L)
{
dict.Remove(key);
}
}
static void CombineAB(Dictionary<char, int> DA, Dictionary<char, int> DB, Dictionary<char, int> DC)
{
foreach (var pair in DA)
{
DC[pair.Key] = pair.Value;
}
foreach (var pair in DB)
{
if (!DA.ContainsKey(pair.Key))
{
DC[pair.Key] = pair.Value;
}
}
}
static void CombineAB2(Dictionary<char, int> DA, Dictionary<char, int> DB, Dictionary<char, int> DC)
{
foreach (var pair in DB)
{
DC[pair.Key] = pair.Value;
}
foreach (var pair in DA)
{
DC[pair.Key] = pair.Value;
}
}
static void Main(string[] args)
{
Dictionary<char, int> dicA = new Dictionary<char, int>();
InitDic(dicA);
PrintDic(dicA);
Console.WriteLine();
Deleven(dicA);
PrintDic(dicA);
Console.WriteLine();
Dictionary<char, int> dicB = new Dictionary<char, int>();
InitDic(dicB);
PrintDic(dicB);
Console.WriteLine();
Deleven(dicB);
PrintDic(dicB);
Console.WriteLine();
Dictionary<char, int> dicC = new Dictionary<char, int>();
CombineAB(dicA,dicB,dicC);
//或者 CombineAB2(dicA,dicB,dicC);
PrintDic(dicC);
}
}
}Question 2: Dictionary and List Conversion
1. Randomly generate a list of strings
2. Use the first item in this list as key, the second item as value; the third item as key, the fourth item as value...and so on. generate a new dictionary
3. Then convert this new dictionary into a new list
using System;
using System.Collections.Generic;
using System.Linq;
namespace ConsoleApp10
{
class Program
{
static string Randomxiang()
{
Random R = new Random();
string str = string.Empty;
string Rch = "ABCDEFGHIJKLMNOPQRSTUWVXYZ0123456789abcdefghijklmnopqrstuvwxyz";
//string[] Rch = new string[R.Next(0, 10000)];
for (int i = 0; i < 2; i++)
{
str += Rch[R.Next(Rch.Length)];
}
return str;
}
static string[] Randomstr(int length)
{
string[] strs = new string[length];
for (int i = 0; i < length; i++)
{
strs[i] = Randomxiang();
}
return strs;
}
static void PrintString(string[] str)
{
for (int i = 0; i < str.Length; i++)
{
Console.Write(str[i]);
Console.Write(" ");
}
Console.WriteLine();
}
static void PrintDic(Dictionary<string, string> dict)
{
foreach (var pair in dict)
{
Console.WriteLine("(" + pair.Key + " " + pair.Value + ")");
}
}
static List<string> CrList(Dictionary<string,string> dict)
{
List<string> L = new List<string>();
foreach(var pair in dict)
{
L.Add(pair.Key);
L.Add(pair.Value);
}
return L;
}
static void PrintList(List<string> list)
{
for(int i = 0; i < list.Count; i++)
{
Console.Write(list[i] + " ");
}
}
static void Main(string[] args)
{
int n = int.Parse(Console.ReadLine());
string[] str = Randomstr(n);
PrintString(str);
Dictionary<string, string> D1 = new Dictionary<string, string>();
for (int i = 0; i < n; i += 2)
{
D1.Add(str[i], str[i + 1]);
}
PrintDic(D1);
PrintList(CrList(D1));
}
}
}Question 3: C# Advanced Dictionary Nesting
1. Create a dictionary dictA, where Key is a string and Value is an integer.
2. Add a total of 26 keys from "a" to "z" to this dictionary, and the values are random numbers from 1 to 10.
3. Create dictionary dictB again in the same way.
Build a complex new dictionary Dictionary<string, List<int>> dictC;
Merge dictA and dictB, the part with the same Key, keep all the values
(A and B may have duplicate Keys, but since the value of dictC is a list, multiple values can be reserved).
using System;
using System.Collections.Generic;
using System.Text;
namespace ConsoleApp1
{
class Program
{
static void InitDic(Dictionary<char,int> dict)
{
Random r = new Random();
string a = $"a";
int asc = Asc(a);
for(int i = 0; i < 26; i++)
{
dict.Add((char)asc, r.Next(1, 10));
asc++;
}
}
public static int Asc(string s)
{
if (s.Length == 1)
{
ASCIIEncoding a = new ASCIIEncoding();
int b = (int)a.GetBytes(s)[0];
return b;
}
else
{
throw new Exception("String is not vaild");
}
}
public static char Cha(string s)
{
int a = int.Parse(s);
if(a>0 && a < 255)
{
char c = (char)a;
return c;
}
else
{
throw new Exception("String is not vaild");
}
}
static void PrintDic(Dictionary<char,int> dict)
{
foreach(var Pair in dict)
{
Console.Write("("+Pair.Key + " " + Pair.Value+")");
}
Console.WriteLine();
}
static void PrintDicC(Dictionary<string,List<int>> dict)
{
foreach (var pair in dict)
{
foreach(var val in pair.Value)
{
Console.Write("(" + pair.Key + " " + val + ")");
}
}
Console.WriteLine();
}
static void Main()
{
Dictionary<char, int> dictA = new Dictionary<char, int>();
InitDic(dictA);
PrintDic(dictA);
Dictionary<char, int> dictB = new Dictionary<char, int>();
InitDic(dictB);
PrintDic(dictB);
Dictionary<string, List<int>> dictC = new Dictionary<string, List<int>>();
foreach(var paira in dictA)
{
List<int> list = new List<int>();
string str = paira.Key.ToString();
foreach(var pairb in dictB)
{
if(pairb.Key == paira.Key)
{
list.Add(paira.Value);
list.Add(pairb.Value);
}
}
dictC.Add(str,list);
}
PrintDicC(dictC);
}
}
}