Python JSON decoding error TypeError: can't use a string pattern on a bytes-like object [duplicate]

Question

Hi there i am coding in python trying to make a user friendly currency exchange app for a school project but have encountered and error with trying to decode json for the exchange rates. The code i'm using is:

import urllib.request
import json
(str) = "http://rate-exchange.appspot.com/currency?from=FRM&to=TO&q=AM";
(str) = (str.replace("FRM", "GBP"))
(str) = (str.replace("TO", "USD"))
url = (str.replace("AM", "20"))
f = urllib.request.urlopen(url)
data = (f.read(100))
print (data)
json_input = data
decoded = json.loads(json_input)
print ("conversion is: ", decoded["v"])

and the error that i am getting is:

b'{"to": "USD", "rate": 1.66215, "from": "GBP", "v": 33.243000000000002}'
Traceback (most recent call last):
File "C:\Users\jay\My Cubby\get qure.py", line 12, in <module>
decoded = json.loads(json_input)
File "C:\Python33\lib\json\__init__.py", line 309, in loads
return _default_decoder.decode(s)
File "C:\Python33\lib\json\decoder.py", line 352, in decode
obj, end = self.raw_decode(s, idx=_w(s, 0).end())
TypeError: can't use a string pattern on a bytes-like object

So i was just wondering if anyone had any ideas of how to fix this error? Or if anyone has seen this error before? Thanks in advance for any help J.Rymer

Martijn Pieters · Accepted Answer · 2014-03-12 18:00:58Z

12

In Python 3, you need to decode the bytes return value from urllib.request.urlopen() to a unicode string:

decoded = json.loads(json_input.decode('utf8'))

This makes the assumption that the web service you are using is using the default JSON encoding of UTF-8.

You could check the response for a character set if you don't want to assume:

f = urllib.request.urlopen(url)
charset = f.info().get_param('charset', 'utf8')
data = f.read()
decoded = json.loads(data.decode(charset))

answered Mar 12, 2014 at 18:00

Martijn Pieters

1.1m326 gold badges4.2k silver badges3.4k bronze badges

Sign up to request clarification or add additional context in comments.

2 Comments

jjr2000 Over a year ago

Thanks for the quick responce! And it works 100% so thanks :)

Aaron Lelevier Over a year ago

The first decoded code snippet worked for me in django-rest-framework testing. Thanks

Collectives™ on Stack Overflow

Python JSON decoding error TypeError: can't use a string pattern on a bytes-like object [duplicate]

1 Answer 1

2 Comments

Linked

Hot Network Questions

Collectives™ on Stack Overflow

1 Answer 1

2 Comments

Linked

Related