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This article focuses on "what are the benefits of Pythonic-style code", interested friends may wish to take a look. The method introduced in this paper is simple, fast and practical. Let's let the editor take you to learn what are the benefits of Pythonic-style code.

In Java, something like this:

For index in (index; index

< items.length ; index++) { item = items[index]; ... now do something } 尝试用python来写循环，则非常简洁易懂： for item in items: item.perform_action() 想要更加pythonic，用生成器表达式来写循环： (item.some_attribute for item in items) 这样的写法其实已经接近自然语言，一眼能看出代码意思。 如果你在Python IDE中输入import python，则会看到下面一首诗： 美胜于丑，简胜于繁，这就是Python哲学。 有一本书《effctive python》里面讲到蛮多pythonic的写法，下面列出一些常见的代码。 1、用列表推导式来取代map、filter map、filter需要编写额外的lambda函数，用起来比较复杂，而且效率也不高。 列表推导式则非常简洁，通过循环创建列表。 # 任务:找到列表中可以被2整除的数，并作二次方运算。 # 非pythonic方法 a = [1,2,3,4,5,6,7,8,9,10] result = map(lambda x: x**2 ,filter(lambda x: x%2==0,a)) # pythonic方法 a = [1,2,3,4,5,6,7,8,9,10] result = [x**2 for x in a if x%2==0] 2、用生成器表达式来代替数据量较大的列表推导 列表推导式虽然简洁，但是不适合大数据量的生成，因为可能会把内存占满。这时就要用到生成器表达式，它返回生成器，基本不占用内存。 # 任务:对十亿条数据进行求平方根操作 # 非pythonic方法 a = [1,2,3,4,5,6,7,8,9,10] # 假装这里有十亿个数字 result = [x**0.5 for x in a] # pythonic方法 a = [1,2,3,4,5,6,7,8,9,10]# 假装这里有十亿个数字 result = (x**0.5 for x in a) 3、尽量使用enumerate enumerate可以把迭代器包装成生成器，每次遍历时，会同时列出数据和数据下标。 # 任务:打印列表中每个元素的索引 # 非pythonic方法 a = ['apple','banana','orange'] for i in range(len(a)): print(a[i],':',i) # pythonic方法 a = ['apple','banana','orange'] for i,j in enumerate(a): print(i,':',j) 4、使用with方法处理文件 with语句提供一个有效的机制，让代码更简练，同时在异常产生时，清理工作更简单。 # 任务:读取一个txt文件 # 非pythonic方法 f = open("some_file.txt") try: data = f.read() # 其他文件操作.. finally: f.close() # pythonic方法 with open("some_file.txt") as f: data = f.read() # 其他文件操作... 5、使用map函数 zip() 函数用于将可迭代的对象作为参数，将对象中对应的元素打包成一个个元组，然后返回由这些元组组成的可迭代对象。 # 任务:对比两个列表相同索引位置元素的大小，输出较大值 # 非pythonic方法 a = [1,5,7] b = [2,4,6] for i in range(len(a)): if a[i] >

B [I]: print (a [I]) else: print (b [I]) # pythonic method a = [1mai 5je 7] b = [2je 4je 6] for I dint j in zip (an I b): if I > j: print (I) else: print (j)

6. Write only one sentence per line

# non-pythonic method print ('one'); print (' two') if x = = 1: print ('one') # pythonic method print (' one'); print ('two') if x = = 1: print (' one')

7. Indent

Continuation lines should be aligned with their package elements, either vertically using implicit line joins within parentheses, square brackets, and curly braces, or using hanging line indentation alignment 3.

When using hanging line indentation, you should take into account that the first line should not have parameters, and use indentation to distinguish yourself as a continuation line.

# non-pythonic method # when vertical alignment is not used, do not place parameters on the first line foo = long_function_name (var_one, var_two, var_three, var_four) # when indentation is not distinguished from other lines To add indentation def long_function_name (var_one, var_two, var_three, var_four): print (var_one) # pythonic method # align with the left parenthesis foo = long_function_name (var_one, var_two, var_three, var_four) # distinguish def long_function_name (var_one, var_two, var_three) with more indentation from other lines Var_four): print (var_one) # hanging line indentation should be replaced by a new line foo = long_function_name (var_one, var_two, var_three, var_four)

8. Import import to the branch

# non-pythonic method import sys, os # pythonic method import os import sys from subprocess import Popen, PIPE

9. Exchange the values of two variables

# non-pythonic method a = 'hello' b =' world' temp = an a = b = temp print (a, b) # pythonic method a = 'hello' b =' world' a, b = b, a print (a, b)

10. Use join method to concatenate strings

# non-pythonic method a = ['for i in a: Bauhini print (b) # pythonic method] a = [' wishful recorder print print (b)]

11. Determine whether a value is True, empty list, or None

# non-pythonic method if x = = True: pass if len (y) = 0: pass if z = = None: pass # pythonic method if x: pass if not y: pass if z is None: pass

12. Pythonic style function

Reasonable naming

Have a single function

Include documentation comments

Returns a value

Functions and classes should be separated by two blank lines

Try to use built-in functions

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