*

*

*

*

*

*

# 1with ...: for ...: if ...: try: except: else:

try-except）和业务逻辑（for, if）混在一起。如果你遵守只对管理逻辑使用缩进的规范，那么核心业务逻辑应该立刻脱离出来。

"扁平结构比嵌套结构更好" - The Zen of Python

1.List Comprehension / Generator 表达式

​​​​​​​
result = []for item in item_list: new_item = do_something_with(item)
result.append(item)

result = [do_something_with(item) for item in item_list]

(do_something_with(item) for item in item_list)

2.函数

doubled_list = map(lambda x: x * 2, old_list)

​​​​​​​
from functools import reducesummation = reduce(lambda x, y: x + y, numbers)

>>> a = list(range(10))>>> a[0, 1, 2, 3, 4, 5, 6, 7, 8, 9]>>> all(a)False>>>
any(a)True>>> max(a)9>>> min(a)0>>> list(filter(bool, a))[1, 2, 3, 4, 5, 6, 7,
8, 9]>>> set(a){0, 1, 2, 3, 4, 5, 6, 7, 8, 9}>>> dict(zip(a,a)){0: 0, 1: 1, 2:
2, 3: 3, 4: 4, 5: 5, 6: 6, 7: 7, 8: 8, 9: 9}>>> sorted(a, reverse=True)[9, 8,
7, 6, 5, 4, 3, 2, 1, 0]>>> str(a)'[0, 1, 2, 3, 4, 5, 6, 7, 8, 9]'>>> sum(a)45

3.Extract Functions or Generators

​​​​​​​
results = []for item in item_list: # setups # condition # processing #
calculation results.append(result)

​​​​​​​
def process_item(item): # setups # condition # processing # calculation
return result results = [process_item(item) for item in item_list]

​​​​​​​
results = []for i in range(10): for j in range(i): results.append((i, j))

​​​​​​​
results = [(i, j) for i in range(10) for j in range(i)]

​​​​​​​
# finding the max prior to the current itema = [3, 4, 6, 2, 1, 9, 0, 7, 5, 8]
results = []current_max = 0for i in a: current_max = max(i, current_max)
results.append(current_max) # results = [3, 4, 6, 6, 6, 9, 9, 9, 9, 9]

def max_generator(numbers): current_max = 0 for i in numbers: current_max =
max(i, current_max)        yield current_max a = [3, 4, 6, 2, 1, 9, 0, 7, 5, 8]
results = list(max_generator(a))

​​​​​​​
from itertools import accumulatea = [3, 4, 6, 2, 1, 9, 0, 7, 5, 8]resutls =
list(accumulate(a, max))

【python学习】

GitHub

Gitee