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
使用json.loads:
>>> import json
>>> h = '{"foo":"bar", "foo2":"bar2"}'
>>> d = json.loads(h)
>>> d
{u'foo': u'bar', u'foo2': u'bar2'}
>>> type(d)
<type 'dict'>
其他回答
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。
总结:
import ast, yaml, json, timeit
descs=['short string','long string']
strings=['{"809001":2,"848545":2,"565828":1}','{"2979":1,"30581":1,"7296":1,"127256":1,"18803":2,"41619":1,"41312":1,"16837":1,"7253":1,"70075":1,"3453":1,"4126":1,"23599":1,"11465":3,"19172":1,"4019":1,"4775":1,"64225":1,"3235":2,"15593":1,"7528":1,"176840":1,"40022":1,"152854":1,"9878":1,"16156":1,"6512":1,"4138":1,"11090":1,"12259":1,"4934":1,"65581":1,"9747":2,"18290":1,"107981":1,"459762":1,"23177":1,"23246":1,"3591":1,"3671":1,"5767":1,"3930":1,"89507":2,"19293":1,"92797":1,"32444":2,"70089":1,"46549":1,"30988":1,"4613":1,"14042":1,"26298":1,"222972":1,"2982":1,"3932":1,"11134":1,"3084":1,"6516":1,"486617":1,"14475":2,"2127":1,"51359":1,"2662":1,"4121":1,"53848":2,"552967":1,"204081":1,"5675":2,"32433":1,"92448":1}']
funcs=[json.loads,eval,ast.literal_eval,yaml.load]
for desc,string in zip(descs,strings):
print('***',desc,'***')
print('')
for func in funcs:
print(func.__module__+' '+func.__name__+':')
%timeit func(string)
print('')
结果:
*** short string ***
json loads:
4.47 µs ± 33.4 ns per loop (mean ± std. dev. of 7 runs, 100000 loops each)
builtins eval:
24.1 µs ± 163 ns per loop (mean ± std. dev. of 7 runs, 10000 loops each)
ast literal_eval:
30.4 µs ± 299 ns per loop (mean ± std. dev. of 7 runs, 10000 loops each)
yaml load:
504 µs ± 1.29 µs per loop (mean ± std. dev. of 7 runs, 1000 loops each)
*** long string ***
json loads:
29.6 µs ± 230 ns per loop (mean ± std. dev. of 7 runs, 10000 loops each)
builtins eval:
219 µs ± 3.92 µs per loop (mean ± std. dev. of 7 runs, 1000 loops each)
ast literal_eval:
331 µs ± 1.89 µs per loop (mean ± std. dev. of 7 runs, 1000 loops each)
yaml load:
9.02 ms ± 92.2 µs per loop (mean ± std. dev. of 7 runs, 100 loops each)
结论: 喜欢json.loads
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!
https://docs.python.org/library/json.html
JSON可以解决这个问题,尽管它的解码器希望键和值周围有双引号。如果你不介意换一个黑客…
import json
s = "{'muffin' : 'lolz', 'foo' : 'kitty'}"
json_acceptable_string = s.replace("'", "\"")
d = json.loads(json_acceptable_string)
# d = {u'muffin': u'lolz', u'foo': u'kitty'}
注意,如果你有单引号作为你的键或值的一部分,这将失败,由于不适当的字符替换。只有当您非常厌恶eval解决方案时,才推荐使用此解决方案。
更多关于json的单引号:jQuery。由于转义了JSON中的单引号,parseJSON抛出“无效JSON”错误