习题32：循环和列表

theCount = [1, 2, 3, 4, 5]
fruits = ['apples', 'oranges', 'pears', 'apricots']
change = [1, 'pennies', 2, 'dimes', 3, 'quarters']
# this first kind of for-loop goes through a list
for number in theCount:
    print("This is count %d" % number)
# same as above
for fruit in fruits:
    print("A fruit of type:%s" % fruit)
# also we can go through mixed lists too
# notice we have to use %r since we don't know what's in it
for i in change:
    print("I got %r" % i)
# we can also build lists,first start with an empty one
elements = []
# then use the range function to do 0 to 5 counts
for i in range(0, 6):
    print("Adding %d to the list." % i)
    # append is a function that lists understand
    elements.append(i)
# now we can print them out too
for i in elements:
    print("Element was:%d" % i)

三个实例for-loop

range(n1,n2)，包含n1不包含n2

This is count 1
This is count 2
This is count 3
This is count 4
This is count 5
A fruit of type:apples
A fruit of type:oranges
A fruit of type:pears
A fruit of type:apricots
I got 1
I got 'pennies'
I got 2
I got 'dimes'
I got 3
I got 'quarters'
Adding 0 to the list.
Adding 1 to the list.
Adding 2 to the list.
Adding 3 to the list.
Adding 4 to the list.
Adding 5 to the list.
Element was:0
Element was:1
Element was:2
Element was:3
Element was:4
Element was:5

1. 注意一下 range 的用法。查一下 range 函数并理解它。

2. 在第 22 行，你可以可以直接将 elements 赋值为 range(0,6)，而无需使用 for 循环？

3. 在 Python 文档中找到关于列表的内容，仔细阅读以下，除了 append 以外列表还支持哪些操作？

习题33：While循环

i = 0
numbers = []
while i < 6:
    print("At the top i is %d" % i)
    numbers.append(i)
    i += 1
    print("Numbers nuw: ", numbers)
    print("At the bottom i is %d" % i)
print("The numbers: ")
for num in numbers:
    print(num)

At the top i is 0
Numbers nuw:  [0]
At the bottom i is 1
At the top i is 1
Numbers nuw:  [0, 1]
At the bottom i is 2
At the top i is 2
Numbers nuw:  [0, 1, 2]
At the bottom i is 3
At the top i is 3
Numbers nuw:  [0, 1, 2, 3]
At the bottom i is 4
At the top i is 4
Numbers nuw:  [0, 1, 2, 3, 4]
At the bottom i is 5
At the top i is 5
Numbers nuw:  [0, 1, 2, 3, 4, 5]
At the bottom i is 6
The numbers: 
0
1
2
3
4
5

1. 将这个 while 循环改成一个函数，将测试条件(i < 6)中的 6 换成一个变量。

def outputNumber(number):
    i = 0
    numbers = []
    while i < number:
        print("At the top i is %d" % i)
        numbers.append(i)
        i += 1
        print("Numbers nuw: ", numbers)
        print("At the bottom i is %d" % i)
    print("The numbers: ")
    for num in numbers:
        print(num)

又想吐槽一下，由于变量没有定义，导致函数对象的参数的类型根本不清楚，很容易弄错。。。反正就是觉得python不行，呵呵

2. 使用这个函数重写你的脚本，并用不同的数字进行测试。

3. 为函数添加另外一个参数，这个参数用来定义第 8 行的加值 + 1 ，这样你就可以让它任意加值了。

4. 再使用该函数重写一遍这个脚本。看看效果如何。

5. 接下来使用 for-loop 和 range 把这个脚本再写一遍。你还需要中间的加值操作吗？如果你不去掉它，会有什么样的结果？

def outputNumber1(number):
    numbers = []
    for i in range(0, number):
        print("At the top i is %d" % i)
        numbers.append(i)
        i += 1
        print("Numbers nuw: ", numbers)
        print("At the bottom i is %d" % i)
    print("The numbers: ")
    for num in numbers:
        print(num)

print_r('点个赞吧')；
var_dump('点个赞吧')；
NSLog(@"点个赞吧！")
System.out.println("点个赞吧!");
console.log("点个赞吧!");
print("点个赞吧!");
printf("点个赞吧!\n");
cout << "点个赞吧!" << endl;
Console.WriteLine("点个赞吧!");
fmt.Println("点个赞吧!")
Response.Write("点个赞吧")；
alert（’点个赞吧’）