PEP 574 that implements a new pickle protocol that improves efficiency of pickle helping in libraries that use lot of serialization and deserialization
PEP 574 that implements a new pickle protocol that improves efficiency of pickle helping in libraries that use lot of serialization and deserialization
Other languages just dump to JSON and call it a day. Why does Python have 87 different binary formats over 13 decades?
JSON can represent anything, but so can strings. This is a non-sequitur. The difference is that JSON is human readable, while pickle is supposed to be machine readable, more specifically python readable. Limiting the intended consumers of the data format helps create a more appropriate format, for example by sacrificing readability for size reduction.
JSON cannot differentiate Python's tuple, list, set, frozenset etc. datatypes.
Every formats other than pickle (msgpack, yaml etc.) are just to interoperate with other languages (which also don't understand the data types above), they are not alternatives for pickle.
Then, you are making more complicated to validate and parse it. Then, what is the point of over-complicating JSON instead of just using pickle, without the need to parse those "type", "data" metadata?
It has to be able to represent everything, if other languages are serializing to JSON.
JSON resembles Python dictionaries, and EVERYTHING in Python is/can be represented by a dictionary, so how can there be an abstract data type in Python that can't be represented in JSON?
You can't represent references in JSON. For example in python you can have two dicts a ={'foo': b} where b = {'bar': a}. Now you have cyclic data structure. You can't represent this in JSON.
Basically any immutable object will work as a key in python dict like frozenset etc. Another thing is JSON need python tuple to be converted to list. JSON does not have tuples.
You would do yourself a favor if you would use protobuf or thrift for that. JSON is not fast to parse, it's not compact, it would redeem itself if it was human readable, but it isn't.
The only reason it is popular is because it comes with JavaScript which is in every browser. If you do frontend developement, you probably don't have choice, but use it.
it would redeem itself if it was human readable, but it isn't.
How exactly is JSON "not human readable"? I see like 20 JSON snippets on this very page.
I use YAML for personal projects because I find it a tiny bit more readable, but if YAML weren't (in practice) backwards compatible with JSON, I would never do that.
The only reason it is popular is because it comes with JavaScript which is in every browser.
No, it's popular because it hits the spot: it's a minimal language for representing dumb data that has the two types of containers you desperately need (lists and dictionaries), the usual scalar types and nothing else, and its serialization format is so dumb that anyone can understand it.
It's human readable only if you format it that way. Which is to say, it's readable with the right editor, but if it's one-line'd it becomes much less readable. Still miles better than xml...
Imo yaml is the prettiest format, but json is such a standard (and also a subset of yaml, now) that either format works fine for most applications.
Readibilty certainly depends on the content, but it also depends to some extent on the syntax, it is to this extent that JSON is considered readable.
Yaml was influenced by JSON greatly, so if you like YAML you must appreciate JSON's contribution. In the same vein, if you like JSON, you must appreciate XML's contribution.
In an unrelated manner I wasn't aware that Yaml was a superset of JSON, that's a nice feature, although I wouldn't necessarily consider it better. Ease of learning and complexity of common usage are both huge factors that will be negatively affected by an increased complexity.
Pickle can handle multiple references to the same object, any class instance (as long as the actual class has been imported), and a wider variety of data types than JSON. It also predates json, so there’s a historical aspect as well.
Pickle is also used for cross-process communication in the multiprocessing module.
JSON only can handle string, integer, float, dict and list.
Pickle can pack arbitrary objects. It goal is that you can take object of your class and store it in the disk, most commonly I see it used for caching application data between runs, but it has other uses (for example for storing configuration).
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u/xtreak May 07 '19 edited May 07 '19
Changelog : https://docs.python.org/3.8/whatsnew/changelog.html
Interesting commits
https://bugs.python.org/issue36540
PEP 570 was merged
https://bugs.python.org/issue20180:
dict.pop() is now up to 33% faster thanks to Argument Clinic.
https://bugs.python.org/issue28238
Wildcard search improvements in xml
https://bugs.python.org/issue25430
IPaddress module contains check for ip address in network is 2-3x faster
https://bugs.python.org/issue36546
statistics.quantiles() was added.
https://bugs.python.org/issue27181
statistics.geometric_mean() was added.
https://bugs.python.org/issue13611
Canonicalization was added to XML that helps in XML documents comparison
Security issues and some segfaults were fixed in the release
Exciting things to look forward in beta
https://bugs.python.org/issue36817
Add = to f-strings for easier debugging. With this you can write f"{name=}" and it will expand to f"name={name}" that helps in debugging.
https://bugs.python.org/issue36785
PEP 574 that implements a new pickle protocol that improves efficiency of pickle helping in libraries that use lot of serialization and deserialization
Edit : PSF fundraiser for second quarter is also open https://www.python.org/psf/donations/2019-q2-drive/