C# |检查每个 List 元素是否匹配谓词条件
原文:https://www . geesforgeks . org/c-sharp-check-if-every-list-element-match-the-predicate-conditions/
列表< T >。TrueForAll(谓词< T > ) 用于检查列表< T >中的每个元素是否符合指定谓词定义的条件。
语法:
public bool TrueForAll (Predicate<T> match);
参数:
匹配:是谓词< T >委托定义了检查元素的条件。
返回值:如果列表< T >中的每个元素都符合指定谓词定义的条件，则该方法返回 true ，否则返回 false 。如果列表没有元素，返回值为真。
异常:如果匹配为空，该方法将给出 ArgumentNullException 。
以下程序说明了列表< T >的使用。TrueForAll(谓词< T >)方法:
例 1:
// C# Program to check if every element
// in the List matches the conditions
// defined by the specified predicate
using System;
using System.Collections;
using System.Collections.Generic;
class Geeks {
// function which checks whether an
// element is even or not. Or you can
// say it is the specified condition
private static bool isEven(int i)
{
return ((i % 2) == 0);
}
// Main Method
public static void Main(String[] args)
{
// Creating a List<T> of Integers
List<int> firstlist = new List<int>();
// Adding elements to List
for (int i = 0; i <= 10; i+=2) {
firstlist.Add(i);
}
Console.WriteLine("Elements Present in List:\n");
// Displaying the elements of List
foreach(int k in firstlist)
{
Console.WriteLine(k);
}
Console.WriteLine(" ");
Console.Write("Result: ");
// Checks if all the elements of firstlist
// matches the condition defined by predicate
Console.WriteLine(firstlist.TrueForAll(isEven));
}
}
Output:
Elements Present in List:
0
2
4
6
8
10
Result: True
例 2:
// C# Program to check if every element
//in the List matches the conditions
//defined by the specified predicate
using System;
using System.Collections;
using System.Collections.Generic;
public class Example
{
public static void Main()
{
List<string> lang = new List<string>();
lang.Add("C# language");
lang.Add("C++ language");
lang.Add("Java language");
lang.Add("Pyhton language");
lang.Add("Ruby language");
Console.WriteLine("Elements Present in List:\n");
foreach(string language in lang)
{
Console.WriteLine(language);
}
Console.WriteLine(" ");
Console.Write("TrueForAll(EndsWithLanguage): ");
// Checks if all the elements of lang
// matches the condition defined by predicate
Console.WriteLine(lang.TrueForAll(EndsWithLanguage));
}
// Search predicate returns
// true if a string ends in "language".
private static bool EndsWithLanguage(String s)
{
return s.ToLower().EndsWith("language");
}
}
Output:
Elements Present in List:
C# language
C++ language
Java language
Pyhton language
Ruby language
TrueForAll(EndsWithLanguage): True
参考:
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