в 15:31, 26 мая 2010

2010-05-26T15:31:53Z

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2010-05-26T12:15:58Z

1 версия

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==Add elements to the table and Use the keys to obtain the values==

<source lang="csharp">using System;
using System.Collections;

class HashtableDemo {
public static void Main() {
Hashtable ht = new Hashtable();

ht.Add("a", "A");
ht.Add("b", "B");
ht.Add("c", "C");
ht.Add("e", "E");

// Get a collection of the keys.
ICollection c = ht.Keys;

foreach(string str in c)
Console.WriteLine(str + ": " + ht[str]);
}
}</source>
<pre class=codeResult>a: A
b: B
c: C
e: E</pre>

==Add key-value pair to Hashtable by using the indexer==

<source lang="csharp">using System;
using System.Collections;

class HashtableDemo {
public static void Main() {
Hashtable ht = new Hashtable();

ht.Add("a", "A");
ht.Add("b", "B");
ht.Add("c", "C");
ht.Add("e", "E");

ht["f"] = "F";

// Get a collection of the keys.
ICollection c = ht.Keys;

foreach(string str in c)
Console.WriteLine(str + ": " + ht[str]);
}
}</source>
<pre class=codeResult>a: A
b: B
c: C
e: E
f: F</pre>

==Clear all key/value pairs in a Hashtable==

<source lang="csharp">using System;
using System.Collections;
class MainClass
{
static void Main(string[] args)
{
Hashtable a = new Hashtable(10);

a.Add(100, "Arrays");
a.Add(200, "Classes");

a.Clear();
}
}</source>

==Copy the keys from Hashtable into an array using the CopyTo() method and then display the array contents==

<source lang="csharp">using System;
using System.Collections;
class MainClass
{
public static void Main()
{
Hashtable myHashtable = new Hashtable();
myHashtable.Add("AL", "Alabama");
myHashtable.Add("CA", "California");
myHashtable.Add("FL", "Florida");
myHashtable.Add("NY", "New York");
myHashtable.Add("WY", "Wyoming");
foreach (string myKey in myHashtable.Keys)
{
Console.WriteLine("myKey = " + myKey);
}
foreach(string myValue in myHashtable.Values)
{
Console.WriteLine("myValue = " + myValue);
}

Console.WriteLine("Copying keys to myKeys array");
string[] myKeys = new string[5];
myHashtable.Keys.CopyTo(myKeys, 0);

for (int counter = 0; counter < myKeys.Length; counter++) {
Console.WriteLine("myKeys[" + counter + "] = " + myKeys[counter]);
}
}
}</source>
<pre class=codeResult>myKey = NY
myKey = CA
myKey = FL
myKey = WY
myKey = AL
myValue = New York
myValue = California
myValue = Florida
myValue = Wyoming
myValue = Alabama
Copying keys to myKeys array
myKeys[0] = NY
myKeys[1] = CA
myKeys[2] = FL
myKeys[3] = WY
myKeys[4] = AL</pre>

==Copy the values from Hashtable into an array using the CopyTo() method and then display the array contents==

<source lang="csharp">using System;
using System.Collections;
class MainClass
{
public static void Main()
{
Hashtable myHashtable = new Hashtable();
myHashtable.Add("AL", "Alabama");
myHashtable.Add("CA", "California");
myHashtable.Add("FL", "Florida");
myHashtable.Add("NY", "New York");
myHashtable.Add("WY", "Wyoming");
foreach (string myKey in myHashtable.Keys)
{
Console.WriteLine("myKey = " + myKey);
}
foreach(string myValue in myHashtable.Values)
{
Console.WriteLine("myValue = " + myValue);
}

Console.WriteLine("Copying values to myValues array");
string[] myValues = new string[5];
myHashtable.Values.CopyTo(myValues, 0);
for (int counter = 0; counter < myValues.Length; counter++)
{
Console.WriteLine("myValues[" + counter + "] = " + myValues[counter]);
}
}
}</source>
<pre class=codeResult>myKey = NY
myKey = CA
myKey = FL
myKey = WY
myKey = AL
myValue = New York
myValue = California
myValue = Florida
myValue = Wyoming
myValue = Alabama
Copying values to myValues array
myValues[0] = New York
myValues[1] = California
myValues[2] = Florida
myValues[3] = Wyoming
myValues[4] = Alabama</pre>

==Mark a Hashtable to be Synchronized==

<source lang="csharp">using System;
using System.Collections;
class MainClass
{
static void Main(string[] args)
{
Hashtable a = new Hashtable(10);
Hashtable.Synchronized(a);

}
}</source>

==Remove key/value pairs from Hashtable==

<source lang="csharp">using System;
using System.Collections;
class MainClass
{
static void Main(string[] args)
{
Hashtable a = new Hashtable(10);

a.Add(100, "A");
a.Add(200, "C");

a.Remove(100);
a.Remove(200);
}
}</source>

==Use foreach statement to loop through all keys in a hashtable==

<source lang="csharp">using System;
using System.Collections;
class MainClass
{
public static void Main()
{
Hashtable hash = new Hashtable();
hash.Add("A", "1");
hash.Add("B", "2");
hash.Add("C", "3");
hash.Add("D", "4");
hash.Add("E", "5");

foreach (string firstName in hash.Keys)
{
Console.WriteLine("{0} {1}", firstName, hash[firstName]);
}
}
}</source>
<pre class=codeResult>A 1
B 2
C 3
D 4
E 5</pre>

==Use the ContainsKey() method to check if Hashtable contains a key==

<source lang="csharp">using System;
using System.Collections;
class MainClass
{
public static void Main()
{
Hashtable myHashtable = new Hashtable();
myHashtable.Add("AL", "Alabama");
myHashtable.Add("CA", "California");
myHashtable.Add("FL", "Florida");
myHashtable.Add("NY", "New York");
myHashtable.Add("WY", "Wyoming");
foreach (string myKey in myHashtable.Keys)
{
Console.WriteLine("myKey = " + myKey);
}
foreach(string myValue in myHashtable.Values)
{
Console.WriteLine("myValue = " + myValue);
}

if (myHashtable.ContainsKey("FL"))
{
Console.WriteLine("myHashtable contains the key FL");
}
}
}</source>
<pre class=codeResult>myKey = NY
myKey = CA
myKey = FL
myKey = WY
myKey = AL
myValue = New York
myValue = California
myValue = Florida
myValue = Wyoming
myValue = Alabama
myHashtable contains the key FL</pre>

==Use the ContainsValue() method to check if Hashtable contains a value==

<source lang="csharp">using System;
using System.Collections;
class MainClass
{
public static void Main()
{
Hashtable myHashtable = new Hashtable();
myHashtable.Add("AL", "Alabama");
myHashtable.Add("CA", "California");
myHashtable.Add("FL", "Florida");
myHashtable.Add("NY", "New York");
myHashtable.Add("WY", "Wyoming");
foreach (string myKey in myHashtable.Keys)
{
Console.WriteLine("myKey = " + myKey);
}
foreach(string myValue in myHashtable.Values)
{
Console.WriteLine("myValue = " + myValue);
}

if (myHashtable.ContainsValue("Florida"))
{
Console.WriteLine("myHashtable contains the value Florida");
}
}
}</source>
<pre class=codeResult>myKey = NY
myKey = CA
myKey = FL
myKey = WY
myKey = AL
myValue = New York
myValue = California
myValue = Florida
myValue = Wyoming
myValue = Alabama
myHashtable contains the value Florida</pre>

==Use the Remove() method to remove FL from Hashtable==

<source lang="csharp">using System;
using System.Collections;
class MainClass
{
public static void Main()
{
Hashtable myHashtable = new Hashtable();
myHashtable.Add("AL", "Alabama");
myHashtable.Add("CA", "California");
myHashtable.Add("FL", "Florida");
myHashtable.Add("NY", "New York");
myHashtable.Add("WY", "Wyoming");
foreach (string myKey in myHashtable.Keys)
{
Console.WriteLine("myKey = " + myKey);
}
foreach(string myValue in myHashtable.Values)
{
Console.WriteLine("myValue = " + myValue);
}

Console.WriteLine("Removing FL from myHashtable");
myHashtable.Remove("FL");
}
}</source>
<pre class=codeResult>myKey = NY
myKey = CA
myKey = FL
myKey = WY
myKey = AL
myValue = New York
myValue = California
myValue = Florida
myValue = Wyoming
myValue = Alabama
Removing FL from myHashtable</pre>

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Csharp/CSharp Tutorial/Data Structure/Hashtable - История изменений

в 15:31, 26 мая 2010

Admin: 1 версия