MOOC —— Python语言基础与应用 by 北京大学 第二章 ：Python语言介绍与概览

    import datetime
    
    dtstr = input('Enter the datetime:(20170228):')
    dt = datetime.datetime.strptime(dtstr, "%Y%m%d")
    another_dtstr = dtstr[:4] + '0101'
    another_dt = datetime.datetime.strptime(another_dtstr, "%Y%m%d")
    print(int((dt - another_dt).days)+1)

    Enter the datetime:(20170228):20190108
    8

    # 输入一行字符，分别统计出其中英文字母、空格、数字和其它字符的个数。
    import string   # 不import也行
    
    s = input('input a string:')
    letter = 0
    space = 0
    digit = 0
    other = 0
    for c in s:
    if c.isalpha():
        letter += 1
    elif c.isspace():
        space += 1
    elif c.isdigit():
        digit += 1
    else:
        other += 1
    print('There are %d letters, %d spaces, %d digits, and %d other characters in your string.'
      % (letter, space, digit, other))

    input a string:abc 123 !@#
    There are 3 letters, 2 spaces, 3 digits, and 3 other characters in your string.

    # merge sort
    # 归并排序
    import random
    
    
    def merge_sort(data_list):
    if len(data_list) <= 1:
        return data_list
    middle = int(len(data_list) / 2)
    left = merge_sort(data_list[:middle])
    right = merge_sort(data_list[middle:])
    merged = []
    while left and right:
        merged.append(left.pop(0) if left[0] <= right[0] else right.pop(0))
    merged.extend(right if right else left)
    return merged
    
    
    data_list = [random.randint(1, 100) for _ in range(50)]
    print(merge_sort(data_list))

    [3, 5, 10, 10, 11, 13, 14, 25, 28, 28, 28, 29, 29, 30, 33, 34, 34, 34, 39, 39, 41, 42, 53, 54, 57, 59, 59, 61, 62, 64, 66, 68, 68, 69, 69, 70, 70, 72, 73, 73, 74, 79, 80, 80, 81, 82, 84, 85, 88, 91]

    # 猜数字游戏
    import random
    
    secret = random.randint(1, 100)
    print('''猜数游戏！
    我想了一个1-100的整数，你最多可以猜6次，
    看看能猜出来吗？''')
    tries = 1
    while tries <= 6:
    guess = int(input("1-100的整数，第%d次猜，请输入：" % tries))
    if guess == secret:
        print("恭喜答对了！你只猜了%d次！\n就是这个：%d!" % (tries, secret))
        break
    elif guess > secret:
        print("不好意思，你的数大了一点儿！")
    else:
        print("不好意思，你的数小了一点儿！")
    tries += 1
    else:
    print("哎呀！怎么也没猜中！再见！")

    猜数游戏！
    我想了一个1-100的整数，你最多可以猜6次，
    看看能猜出来吗？
    1-100的整数，第1次猜，请输入：55
    不好意思，你的数大了一点儿！
    1-100的整数，第2次猜，请输入：33
    不好意思，你的数小了一点儿！
    1-100的整数，第3次猜，请输入：45
    不好意思，你的数小了一点儿！
    1-100的整数，第4次猜，请输入：50
    不好意思，你的数大了一点儿！
    1-100的整数，第5次猜，请输入：47
    不好意思，你的数大了一点儿！
    1-100的整数，第6次猜，请输入：46
    恭喜答对了！你只猜了6次！
    就是这个：46!

    >>> import this
    The Zen of Python, by Tim Peters
    
    Beautiful is better than ugly.
    Explicit is better than implicit.
    Simple is better than complex.
    Complex is better than complicated.
    Flat is better than nested.
    Sparse is better than dense.
    Readability counts.
    Special cases aren't special enough to break the rules.
    Although practicality beats purity.
    Errors should never pass silently.
    Unless explicitly silenced.
    In the face of ambiguity, refuse the temptation to guess.
    There should be one-- and preferably only one --obvious way to do it.
    Although that way may not be obvious at first unless you're Dutch.
    Now is better than never.
    Although never is often better than *right* now.
    If the implementation is hard to explain, it's a bad idea.
    If the implementation is easy to explain, it may be a good idea.
    Namespaces are one honking great idea -- let's do more of those!