Clash Royale CLAN TAG#URR8PPP

String containing list and other data types to dictionary without changing the data type in python

I have one string as below:

key_val = "count=2, name=['hello', 'hi'], word='Dial::100', roll=12"


I need to get the dictionary from the string as below:

d_key_val = 'count'=2, 'name'=['hello', 'hi'], 'word'='Dial::100', 'roll'=12


I tried with the following:

regx = r'(?P<key>w+)=(?P<value>[.+?]|d+|S+)'
r_key_val = re_findall(regx, key_val)
for key, value in r_key_val:
d_key_val[key] = value


But it is storing values as all string:

d_key_val = 'count'='2', 'name'="['hello', 'hi']", 'word'="'Dial::100'", 'roll'='12'


Is there any way or regex to store the values as same data type as it has in string?

2 Answers
2

If you are 100% sure that the data is "safe", you could eval it as the parameters to dict:

eval

dict

>>> key_val = "count=2, name=['hello', 'hi'], word='Dial::100', roll=12"
>>> eval("dict(%s)" % key_val)
'count': 2, 'name': ['hello', 'hi'], 'roll': 12, 'word': 'Dial::100'


If you are not sure, better don't use eval, though.

eval

Alternatively, you could use your regex and use ast.literal_eval to evaluate the value:

ast.literal_eval

value

>>> regx = r'(?P<key>w+)=(?P<value>[.+?]|d+|S+)'
>>> k: ast.literal_eval(v) for k, v in re.findall(regx, key_val)
'count': 2, 'name': ['hello', 'hi'], 'roll': 12, 'word': ('Dial::100',)


(Note: I did not check your regex in detail.) You could also try to apply ast.literal_eval to the entire expression, instead of the less safe eval, but this would require some preprocessing, e.g. replacing = with : and adding quotes to the keys, that might not work well with e.g. string values containing those symbols.

ast.literal_eval

eval

=

:

regex cannot do that, but you can! You can write a function like the following that takes the values regex writes out and converts them to the appropriate type.

regex

values

regex

def type_converter(v):
if v[0] == '[' and v[-1] == ']':
v = v.replace('[', '').replace(']', '')
return [type_converter(x) for x in v.split(',')]
try:
v = int(v)
except ValueError:
try:
v = float(v)
except ValueError:
pass
finally:
return v


To add this to your code, simply do:

regx = r'(?P<key>w+)=(?P<value>[.+?]|d+|S+)'
r_key_val = re_findall(regx, key_val)
for key, value in r_key_val:
d_key_val[key] = type_converter(value) # <- this


Example:

lst = ['2', '1.2' ,'foo', '[1, 2]']
print([type(type_converter(x)) for x in lst ])
# [<class 'int'>, <class 'float'>, <class 'str'>, <class 'list'>]


Note that the order in which the try-blocks are written is very important since float('1') does not raise any Errors but the correct type is int!

try

float('1')

int

list

ast.literal_eval

ast.literal_eval

json

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