Useful Python Tricks

Posted on In Views: Word count in article: 2.1k Reading time ≈ 2 mins.
几个常用的Python技巧，第一个例子就震惊了，大部分人都不相信还有这种操作！

使用分隔符号的数字也可以计算，而且看起来数据更加清晰。

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# python3.6
>>> num1 = 10_000_000_000
>>> num2 = 10_000
>>> num1 + num2
10000010000

>>> f'{num1+num2:,}'
'10,000,010,000'

>>> f'{num1+num2:_}'
'10_000_010_000'

一行代码处理简单的 if else

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condition = True
if condition:
    x = 1
else:
    x = 0

x = 1 if condition else 0

for … else… 也挺常用的

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for i in range(10):
    # do something
    if i == 100:
        print("i will break")
        break
else:
    print("代码没有执行到循环中的break")

try … else … 

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condition = 1
try:
    if condition:
        ret = 1 / 0
    print("这是准备前面没有报错才执行的代码")
except Exception as e:
    print(e)
else:
    print("没有异常，我就执行")

'''
condition = 1 时
输出:
division by zero

condition = 0 时
输出：
这是准备前面没有报错才执行的代码
没有异常，我就执行
'''

for 语句中使用 enumerate 来遍历

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names = ['aa', 'bb', 'cc']
for index, name in enumerate(names):
    print(index, name)
'''
0 aa
1 bb
2 cc
'''

names = ['aa', 'bb', 'cc']
ages = [10, 20, 30]
regions = ['nanjing', 'hangzhou', 'shanghai']
for name, age, region in zip(names, ages, regions):
    print(f'{name} is {age} from {region}')
'''
aa is 10 from nanjing
bb is 20 from hangzhou
cc is 30 from shanghai
'''

为对象动态赋予属性：

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class Person():
    pass

person = Person()

first_key = 'name'
first_value = 'banana'

setattr(person, first_key, first_value)
print(person.name)  
# banana

get_first_key = getattr(person, first_key)
print(get_first_key)
# banana

升级一下：

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class Person():
    pass

person = Person()

person_info = {"first": "Tom", "last": "Jenny"}

for key, value in person_info.items():
    setattr(person, key, value)

print(person.first)  # Tom
print(person.last)  # Jenny
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class Person(object):
    def __init__(self, name, gender, **kwargs):
        self.name = name
        self.gender = gender
        for k, v in kwargs.items():
            # dict_items([('age', 25), ('love', 'reading')])
            setattr(self, k, v)

p1 = Person("zyp", 'male', age=25, love="reading")
# print(dir(p1))
print(p1.age)
print(p1.love)