python核心编程第二章习题

"""python核心编程练习2使用的python版本: Python 3.2.3"""def t2_5():    """分别写一个while和for循环，输出整数0～10。    """    i = 0    while i <= 10:        print(i,'', end='')        i += 1    print()    for i in range(0, 11):        print(i,'', end='')    print()def t2_6():    """条件判断。        判断一个数是整数，负数，或者等于0.    """    try:        anum = int(input('Enter a number: '))    except ValueError:        print('what you entered is not a number!!!')    else:        print(anum)def t2_7():    """输入一个字符串，逐个字符输出该字符串。使用while和for    """    astr = input('Enter a string: ')    for eachar in astr:        print(eachar, end='')    print()    strlen = len(astr)    i = 0    while i < strlen:        print(astr[i], end='')        i += 1    print()def t2_8():    """输入5个数，分别存入list和tuple，算出他们的和    """    alist = []    atuple = ()    for i in range(0, 5):        num = int(input('Enter a number: '))        alist.append(num)        atuple = atuple + (num, )        total = 0    for num in alist:        total += num    print(total)    total = 0    for num in atuple:        total += int(num)    print(total)def t2_9():    """输入5个数，存入list和tuple，算出他们的平均值        在python3.2版本中，单除号/实现的是小数除法，可以直接用，不过这里考虑        输入的数可能为浮点数，所以也用float对输入进行转换        如果在2.x版本中，如果输入的是整数，需要先将数转成float，再除    """    alist = []    atuple = ()    # input 5 numbers    for i in range(0, 5):        num = float(input('Enter a number: '))        alist.append(num)        atuple = atuple + (num, ) # 向一个tuple添加元素，要使用tuple相加                                  # 所以这里先办单个数num组成一个只有一个                                  # 元素的tuple再与原来的tuple相加    total = 0    for num in alist:       total += num    print(total/len(alist))    total = 0    for num in atuple:        total += num    print(total/len(atuple))def t2_10():    """让用户输入一个1～100之间的数，如果用户输入的数满足条件，    显示成功并推出，否则显示错误信息，然后再次提示用户输入。    """    prompt = 'Please input a number (1~100): '    while True:        try:            num = int(input(prompt))        except ValueError:            print('Not a number')        else:            if 1 <= num <= 100:                break            else:                print(num, 'not correct')    print('Yes, you got it.')def t2_11():    """带文本菜单的程序。        菜单如下(1)取5个数的和 （2）取5个数的平均值 （X）退出    """    prompts = '''(1)sum of five numbers.(2)average of five numbers.(X)QuitEnter your choice: '''    while True:        choice = input(prompts).strip()[0].lower()        print('\nYou picked [{}]'.format(choice))        if choice not in '12x':            print('Invalid options:', choice)        elif choice == '1':            t2_8()        elif choice == '2':            t2_9()        else:            breakdef t2_15():    """用户输入三个数，保存至不同的变量中。不使用列表或排序算法，    自己写代码来对这三个数进行排序：从大到小，从小到大    """    aa = int(input('Enter a number: '))    bb = int(input('Enter a number: '))    cc = int(input('Enter a number: '))       a, b, c = aa, bb, cc    # from smallest to largest    if a > b:        a, b = b, a # swap two value    if a > c:        a, c = c, a    if b > c:        b, c = c, b    print('{} < {} < {}'.format(a, b, c))    # from largest to smallest    a, b, c = aa, bb, cc    if a < b:        a, b = b, a    if a < c:        a, c = c, a    if b < c:        b, c = c, b    print('{} > {} > {}'.format(a, b, c))def t2_16():    """输入一个文件名，然后读取该文件，并将文件内容输入到屏幕上    """    filename = input('Enter file name: ')    fobj = open(filename, 'r')    for eachline in fobj:        print(eachline, end='') # 默认的print语句会加换行，这里把换行去掉    fobj.close()    if __name__ == '__main__':    #t2_5()    #t2_6()    #t2_7()    #t2_8()    #t2_9()    #t2_10()    #t2_11()    #t2_15()    #t2_16()