每个新手程序员都应该知道的Python开发技巧

• 字符串操作

• 列表推导

• Lambda 和 Map 函数

• 在一行里使用 if elif 和 else 条件判断

• zip() 函数

字符串操作

>>> my_string = 'Hi Medium..!'
>>> print(my_string * 2)
Hi Medium..!Hi Medium..!
>>> print(my_string + ' I love Python' * 2)
Hi Medium..! I love Python I love Python

>>> print(my_string[::-1])
!..muideM iH
>>> my_list = [1,2,3,4,5]
>>> print(my_list[::-1])
[5, 4, 3, 2, 1]

>>> word_list = ['awesome', 'is', 'this']
>>> print(' '.join(word_list[::-1]) + '!')
this is awesome!

列表推导

>>> def stupid_func(x):
>>>     return x**2 + 5

>>> my_list = [1, 2, 3, 4, 5]
>>> new_list = []
>>> for x in my_list:
>>>     if x % 2 != 0:
>>>         new_list.append(stupid_func(x))
>>> print(new_list)
[6, 14, 30]

>>> my_list = [1, 2, 3, 4, 5]
>>> print([stupid_func(x) for x in my_list if x % 2 != 0])
[6, 14, 30]

>>> for item in list:
>>>     if conditional:
>>>         expression

>>> print([x ** 2 + 5 for x in my_list if x % 2 != 0])
[6, 14, 30]

Lambda 和 Map

>>> stupid_func = (lambda x : x ** 2 + 5)
>>> print([stupid_func(1), stupid_func(3), stupid_func(5)])
[6, 14, 30]

>>> my_list = [2, 1, 0, -1, -2]
>>> print(sorted(my_list))
[-2, -1, 0, 1, 2]

>>> print(sorted(my_list, key = lambda x : x ** 2))
[0, -1, 1, -2, 2]

>>> print(list(map(lambda x, y : x * y, [1, 2, 3], [4, 5, 6])))
[4, 10, 18]

>>> x, y = [1, 2, 3], [4, 5, 6]
>>> z = []
>>> for i in range(len(x)):
>>>     z.append(x[i] * y[i])
>>> print(z)
[4, 10, 18]

>>> x = int(input())
>>> if x >= 10:
>>>     print('Horse')
>>> elif 1 < x < 10:
>>>     print('Duck')
>>> else:
>>>     print('Baguette')

print('Horse' if x >= 10 else 'Duck' if 1 < x < 10 else 'Baguette')

zip()

>>> first_names = ['Peter', 'Christian', 'Klaus']
>>> last_names = ['Jensen', 'Smith', 'Nistrup']
>>> print([' '.join(x) for x in zip(first_names, last_names)])
['Peter Jensen', 'Christian Smith', 'Klaus Nistrup']

>>> print([' '.join(x) for x in zip(first_names, last_names[::-1])])
['Peter Nistrup', 'Christian Smith', 'Klaus Jensen']

结束语