Chapter 4 Python 代码结构

# if - elif - else conditions

guess_me = 7

if guess_me == 7:
    print('right')

elif guess_me > 7:
    print('too high')

else:
    print("too low")

start = 1

# while loop

while 1:
    if start < guess_me:
        print('too low')


    elif start == guess_me:
        print('found it')

    elif start > guess_me:
        print("oops")
        print('start = ', start)
        break

    start += 1

# for loop

a_list = []

for i in range(3, -1, -1):
    a_list.append(i)

for i in a_list:
    print(i)

# list deriving
even_number = [number for number in range(10) if number % 2 == 0 ]
print(even_number)

odd_number = [number for number in range(10) if number % 2 != 0 ]
print(odd_number)

# generator (this is fun! )
for got_number in ('Got %s' %number for number in range(10)):
    print (got_number)

# function

def good():
    return ['Harry', 'Ron', 'Hermione']

print(good())

a = good()
for i in a:
    print(i)

# generator function

def generator_function(first = 0, last = 20, step = 5):
    number = first
    while number < last:
        yield number
        number += step

for i in generator_function():
    print(i)

b = generator_function(0, 100, 20)

print(type(b))

for i in b:
    print(i)

def generator_function_two(first = 1, last = 9 ):
    time = 0
    for i in generator_function(first, last, 1):
        time += 1
        if i % 2 != 0:
            yield i

for count, number in enumerate(generator_function_two(), 1):
    if count == 3:
        print('the third number is ', number)

# decorator
def test(func):
    def new_fuction(*args, **kargs):
        print('starting ', func.__name__)
        result = func(*args, **kargs)
        print('the result is ',result)
        print(func.__name__, ' running complete')
        return result     # easy to miss
    return new_fuction

@test
def add_int(first, second):
    return first + second


add_int(3, 6)


# define exception

class OopsException(Exception):
    pass

try:
    raise OopsException('what??')
except OopsException as ex:
    print("wtf")


# zip function

list_one = [1, 2, 3]
list_two = [4, 5, 6]
for i in zip(list_one, list_two):
    print(i)
    for j in i:
        print(j)  # ignore this

# unzip

total_list = zip(list_one, list_two)

for list in zip(*total_list):
    print(list)