如何将字典的str表示,如下面的字符串,转换为字典?
s = "{'muffin' : 'lolz', 'foo' : 'kitty'}"
我不喜欢使用eval。我还能用什么?
主要原因是,我同事写的一个类,将所有输入转换为字符串。我没有心情去修改他的课程,去处理这个问题。
如何将字典的str表示,如下面的字符串,转换为字典?
s = "{'muffin' : 'lolz', 'foo' : 'kitty'}"
我不喜欢使用eval。我还能用什么?
主要原因是,我同事写的一个类,将所有输入转换为字符串。我没有心情去修改他的课程,去处理这个问题。
当前回答
你可以使用内置的ast.literal_eval:
>>> import ast
>>> ast.literal_eval("{'muffin' : 'lolz', 'foo' : 'kitty'}")
{'muffin': 'lolz', 'foo': 'kitty'}
这比使用eval更安全。正如它自己的文件所说:
>>> 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.
例如:
>>> 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'
>>> 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
其他回答
使用json。ast库消耗大量内存,而且速度较慢。我有一个进程,需要读取156Mb的文本文件。Ast有5分钟的延迟转换字典json和1分钟使用60%的内存!
你可以使用内置的ast.literal_eval:
>>> import ast
>>> ast.literal_eval("{'muffin' : 'lolz', 'foo' : 'kitty'}")
{'muffin': 'lolz', 'foo': 'kitty'}
这比使用eval更安全。正如它自己的文件所说:
>>> 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.
例如:
>>> 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'
>>> 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
Siva Kameswara Rao Munipalle的优化代码
s = s.replace("{", "").replace("}", "").split(",")
dictionary = {}
for i in s:
dictionary[i.split(":")[0].strip('\'').replace("\"", "")] = i.split(":")[1].strip('"\'')
print(dictionary)
不使用任何库(python2):
dict_format_string = "{'1':'one', '2' : 'two'}"
d = {}
elems = filter(str.isalnum,dict_format_string.split("'"))
values = elems[1::2]
keys = elems[0::2]
d.update(zip(keys,values))
注意:由于它有硬编码的分割(“'”)将只适用于数据是“单引号”的字符串。
注2:在python3中,您需要将filter()包装为list()以获取list。
我的字符串里面没有引号: s = '日期:2022-11-29T10:57:01.024Z,大小:910.11 KB'
我的解决方案是使用str.split: {k: k v, v在地图(λd: d.split(“:”),s.split (" ")}