Learn Python The Hard Way学习(19) - 函数和变量

函数包含比较多的东西，很难一下理解，不过不用担心，对照上一节的检查清单练习，最后会明白的。

这里有个细节可能你没注意到，我们现在加强一下：函数里面的变量和脚本中的变量是没有关联的。

看下面的程序：

def cheese_and_crackers(cheese_count, boxes_of_crackers):
    print "You have %d cheeses!" % cheese_count
    print "You hava %d boxes of crackers!" % boxes_of_crackers
    print "Man that's enough for a party!"
    print "Get a blanket.\n"


print "We can just give the function numbers directly:"
cheese_and_crackers(20, 30)


print "OR, we can use variables from our script:"
amount_of_cheese = 10
amount_of_crackers = 50


cheese_and_crackers(amount_of_cheese, amount_of_crackers)


print "We can even do match inside too:"
cheese_and_crackers(10 + 20, 5 + 6)


print "And we can combine the two,variables and math:"
cheese_and_crackers(amount_of_cheese + 100, amount_of_crackers + 1000)

上面展示所有不同的调用cheese_and_crackers函数的方法。

函数中的参数和变量类似，变量赋值的时候用=，函数也是这样给参数赋值。

运行结果

root@he-desktop:~/mystuff# python ex19.py

We can just give the function numbers directly:

You have 20 cheeses!

You hava 30 boxes of crackers!

Man that's enough for a party!

Get a blanket.

OR, we can use variables from our script:

You have 10 cheeses!

You hava 50 boxes of crackers!

Man that's enough for a party!

Get a blanket.

We can even do match inside too:

You have 30 cheeses!

You hava 11 boxes of crackers!

Man that's enough for a party!

Get a blanket.

And we can combine the two,variables and math:

You have 110 cheeses!

You hava 1050 boxes of crackers!

Man that's enough for a party!

Get a blanket.

root@he-desktop:~/mystuff#

加分练习

1. 给脚本添加注释。

2. 反过来读一下代码。

3. 自己写一个函数，然后用10种方法调用。