hcnak.blog

posted at 2017-01-16 22:48:25 +0000

Python转换字符串字典为Python字典类型数据

假设我们有以下字符串数组：

stra = "{'muffin' : 'lolz', 'foo' : 'kitty'}"

大家知道可以通过 eval 函数转换，但是有一种更加安全的方法，那就是literal_eval

如下：

import ast 
stra = "{'muffin' : 'lolz', 'foo' : 'kitty'}" 
ast.literal_eval(stra) 

help(ast.literal_eval) Help on function literal_eval in module ast: literal_eval(node_or_string) Safely evaluate an expression node or a string containing a Python expression. The string or node provided may only consist of the following Python literal structures: strings, numbers, tuples, lists, dicts, booleans, and None.

给出使用eval和 literal_eval转换时候的出错比较：

eval:

eval("shutil.rmtree('mongo')") 
Traceback (most recent call last): 
  File "<stdin>", line 1, in <module> 
  File "<string>", line 1, in <module> 
  File "/opt/Python-2.6.1/lib/python2.6/shutil.py", line 208, in rmtree onerror(os.listdir, path, sys.exc_info()) 
  File "/opt/Python-2.6.1/lib/python2.6/shutil.py", line 206, in rmtree names = os.listdir(path) 
  OSError: [Errno 2] No such file or directory: 'mongo' 

literal_eval:

> ast.literal_eval("shutil.rmtree('mongo')") 
Traceback (most recent call last): 
  File "<stdin>", line 1, in <module> 
  File "/opt/Python-2.6.1/lib/python2.6/ast.py", line 68, in literal_eval return _convert(node_or_string) 
  File "/opt/Python-2.6.1/lib/python2.6/ast.py", line 67, in _convert raise ValueError('malformed string') 
  ValueError: malformed string

last updated on 2022-07-27 01:57:54 +0000