python3 _笨方法学Python_日记_DAY4

Posted 2020-10-24 Mrfri

Day4

• 习题  19:  函数和变量

 1 def cheese_and_crackers(cheese_count, boxes_of_crackers):
 2     print("You have %d cheeses!" % cheese_count)
 3     print("You have %d boxes of crackers!" % boxes_of_crackers)
 4     print("Man that\'s enough for a party!")
 5     print("Get a blanket.\\n")
 6 
 7 print("We can just give the function numbers directly:")
 8 cheese_and_crackers(20,30)
 9 
10 print("OR,we can use variables from our script:")
11 amount_of_cheese = 10
12 amount_of_crackers = 50
13 
14 cheese_and_crackers(amount_of_cheese, amount_of_crackers)
15 
16 print("We can even do math inside too:")
17 cheese_and_crackers(10+20, 5+6)
18 
19 print("And we can combine the two, variables and math:")
20 cheese_and_crackers(amount_of_cheese + 100,
21                     amount_of_crackers + 1000)

结果：

We can just give the function numbers directly:
You have 20 cheeses!
You have 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 have 50 boxes of crackers!
Man that\'s enough for a party!
Get a blanket.

We can even do math inside too:
You have 30 cheeses!
You have 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 have 1050 boxes of crackers!
Man that\'s enough for a party!
Get a blanket.

自己编一个函数：

1 def pingfang(x):
2     return x*x
3 
4 print(pingfang(5))
5 
6 y=pingfang(6)
7 print(y)

25
36

• 习题  20:  函数和文件

 1 from sys import argv
 2 
 3 #脚本名，参数一（导入的文件）
 4 script, input_file = argv
 5 
 6 def print_all(f):       #定义一个新函数：将文件全打印出来
 7     print(f.read())
 8 
 9 def rewind(f):          #定义新函数：将文件指针移动到最开头
10     f.seek(0)
11 
12 def print_a_line(line_count, f): #定义新函数：打印（行号，这行的内容）
13     print(line_count, f.readline())
14 
15 current_file = open(input_file)  #定义变量，打开导入的文件为当前文件
16 
17 print("First let\'s print the whole file:\\n")
18 
19 print_all(current_file)
20 
21 print("Now let\'s rewind, kinds of like a tape.")
22 rewind(current_file)
23 
24 print("Let\'s print three lines:")
25 
26 current_file = 1             
27 print_a_line(current_file, current_file)
28 
29 current_file = current_file + 1
30 print_a_line(current_file, current_file)
31 
32 current_file = current_file + 1
33 print_a_line(current_file, current_file)

• 习题  21:  函数可以返回东西

 1 def add(a, b):
 2     print("ADDING %d + %d" % (a, b))
 3     return a + b
 4 
 5 def subtract(a, b):
 6     print("SUBTRACTING %d - %d" % (a, b))
 7     return a - b
 8 
 9 def multipy(a, b):
10     print("MULTIPLAYING %d * %d" % (a, b))
11     return a * b
12 
13 def divide(a, b):
14     print("DIVIDING %d / %d" % (a, b))
15     return a / b
16 
17 print("Let\'s do some math with just functions!")
18 
19 age = add(30, 5)
20 height = subtract(78,4)
21 weight = multipy(90,2)
22 iq = divide(100,2)
23 
24 print("Age: %d, Height: %d, Weight: %d, IQ: %d" % (age, height, weight, iq))
25 
26 #A puzzle for the extra credit, type it in anyway.
27 print("Here is a puzzle.")
28 
29 what = add(age, subtract(height, multipy(weight, divide(iq,2))))
30 
31 print("That becomes:\\n",what,"\\nCan you do it by hand?")

Let\'s do some math with just functions!
ADDING 30 + 5
SUBTRACTING 78 - 4
MULTIPLAYING 90 * 2
DIVIDING 100 / 2
Age: 35, Height: 74, Weight: 180, IQ: 50
Here is a puzzle.
DIVIDING 50 / 2
MULTIPLAYING 180 * 25
SUBTRACTING 74 - 4500
ADDING 35 + -4426
That becomes:
-4391.0
Can you do it by hand?

谜题解答

1 def jia(a,b,c,d,e):
2     print("谜题答案，一口气全算对\\n %d + (%d - %d * %d / %d)" % (a,b,c,d,e))
3     return a+(b-c*d/e)
4 
5 this=jia(35,74,180,50,2)
6 print(this)
7 print(this==what)

谜题答案，一口气全算对
35 + (74 - 180 * 50 / 2)
-4391.0
True