Question

我有一个项目列表

 alist = ['dog', 'cat', 'fish']

我想返回所有唯一的无序对，所以在这种情况下：

 (dog,cat)(dog,fish)(fish,cat)

itertools.combinations没有考虑无序条件，所以它不是我需要的。

Answer 1

itertools 的问题在哪里？

('dog', 'cat')
('dog', 'fish')
('cat', 'fish')

输出：

using System;
using System.Collections.Generic;
using System.ComponentModel;
using System.Data;
using System.Diagnostics;
using System.Drawing;
using System.Linq;
using System.Text;
using System.Threading.Tasks;
using System.Windows.Forms;

namespace MessageLoop
{
    public partial class Form1 : Form
    {
        /// <summary>
        ///  WM_WTSSESSION_CHANGE message number for filtering in WndProc
        /// </summary>
        private const int WM_WTSSESSION_CHANGE = 0x2b1;

        public Form1()
        {
            InitializeComponent();
            NativeWrapper.WTSRegisterSessionNotification(this, SessionNotificationType.NOTIFY_FOR_ALL_SESSIONS);
        }
        protected override void OnClosing(CancelEventArgs e)
        {
            NativeWrapper.WTSUnRegisterSessionNotification(this);
            base.OnClosing(e);
        }
        protected override void WndProc(ref Message m)
        {
            if (m.Msg == WM_WTSSESSION_CHANGE)
            {
                int eventType = m.WParam.ToInt32();
                int sessionId = m.LParam.ToInt32();
                WtsSessionChange reason = (WtsSessionChange)eventType;
                Trace.WriteLine(string.Format("SessionId: {0}, Username: {1}, EventType: {2}", 
                    sessionId, NativeWrapper.GetUsernameBySessionId(sessionId), reason));
            }
            base.WndProc(ref m);
        }
    }
}

从列表中Python中的无序对（对集）

1 个答案: