python3 _笨方法学Python_日记_DAY4

Day4

• 习题  19:  函数和变量

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

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 math 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)

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：

def pingfang(x):
    return x*x

print(pingfang(5))

y=pingfang(6)
print(y)

25
36

• 习题  20:  函数和文件

from sys import argv

#脚本名，参数一（导入的文件）
script, input_file = argv

def print_all(f):       #定义一个新函数：将文件全打印出来
    print(f.read())

def rewind(f):          #定义新函数：将文件指针移动到最开头
    f.seek(0)

def print_a_line(line_count, f): #定义新函数：打印（行号，这行的内容）
    print(line_count, f.readline())

current_file = open(input_file)  #定义变量，打开导入的文件为当前文件

print("First let's print the whole file:
")

print_all(current_file)

print("Now let's rewind, kinds of like a tape.")
rewind(current_file)

print("Let's print three lines:")

current_file = 1             
print_a_line(current_file, current_file)

current_file = current_file + 1
print_a_line(current_file, current_file)

current_file = current_file + 1
print_a_line(current_file, current_file)

• 习题  21:  函数可以返回东西

def add(a, b):
    print("ADDING %d + %d" % (a, b))
    return a + b

def subtract(a, b):
    print("SUBTRACTING %d - %d" % (a, b))
    return a - b

def multipy(a, b):
    print("MULTIPLAYING %d * %d" % (a, b))
    return a * b

def divide(a, b):
    print("DIVIDING %d / %d" % (a, b))
    return a / b

print("Let's do some math with just functions!")

age = add(30, 5)
height = subtract(78,4)
weight = multipy(90,2)
iq = divide(100,2)

print("Age: %d, Height: %d, Weight: %d, IQ: %d" % (age, height, weight, iq))

#A puzzle for the extra credit, type it in anyway.
print("Here is a puzzle.")

what = add(age, subtract(height, multipy(weight, divide(iq,2))))

print("That becomes:
",what,"
Can 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

def jia(a,b,c,d,e):
    print("谜题答案，一口气全算对
 %d + (%d - %d * %d / %d)" % (a,b,c,d,e))
    return a+(b-c*d/e)

this=jia(35,74,180,50,2)
print(this)
print(this==what)

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