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- python - Check if a given key already exists in a dictionary - Stack . . .
I would recommend using the setdefault method instead It sounds like it will do everything you want >>> d = {'foo':'bar'} >>> q = d setdefault('foo','baz') #Do not override the existing key >>> print q #The value takes what was originally in the dictionary bar >>> print d {'foo': 'bar'} >>> r = d setdefault('baz',18) #baz was never in the dictionary >>> print r #Now r has the value supplied
- python - Determine whether a key is present in a dictionary - Stack . . .
In Python 3, dict objects no longer have a has_key() method, so version-portability-wise, the in operator is better – martineau Commented Feb 16, 2016 at 1:52
- python - Most efficient method to check if dictionary key exists and . . .
Conclusion: construction key in dict is generally fastest, outperformed only by try except in case of valid key, because it doesn't perform if operation (note however try except is significantly slower for invalid keys : therefore, since the whole point is you don't know if key is valid, then given an unknown probability of valid vs invalid
- python - How to check if a value exists in a dictionary . . . - Stack . . .
In Python 2, it's more efficient to use "one" in d itervalues() instead Note that this triggers a linear scan through the values of the dictionary, short-circuiting as soon as it is found, so this is a lot less efficient than checking whether a key is present
- python - Iterating over dictionaries using for loops - Stack Overflow
For Python 3 x: for key, value in d items(): For Python 2 x: for key, value in d iteritems(): To test for yourself, change the word key to poop In Python 3 x, iteritems() was replaced with simply items(), which returns a set-like view backed by the dict, like iteritems() but even better This is also available in 2 7 as viewitems()
- Python Dictionary Check if Key Exists - Stack Overflow
Let's note up front that in python a 'dictionary' is a data structure You're using a third-party library to perform dictionary lookups (as in lexical meanings) You also need to know how to tell if a python dictionary data structure contains a key Keep these uses of the word 'dictionary' separate in your mind or you will rapidly get confused
- python - Check if a given key already exists in a dictionary and . . .
It also avoids the duplicate key lookup in the dictionary as it would in key in my_dict and my_dict[key] is not None what is interesting if lookup is expensive For the actual problem that you have posed, i e incrementing an int if it exists, or setting it to a default value otherwise, I also recommend the
- python check multi-level dict key existence - Stack Overflow
Many SO posts show you how to efficiently check the existence of a key in a dictionary, e g , Check if a given key already exists in a dictionary How do I do this for a multi level key? For example, if d["a"]["b"] is a dict, how can I check if d["a"]["b"]["c"]["d"] exists without doing something horrendous like this:
- Elegant way to check if a nested key exists in a dict?
I suggest you to use python-benedict, a solid python dict subclass with full keypath support and many utility methods You just need to cast your existing dict: s = benedict(s) Now your dict has full keypath support and you can check if the key exists in the pythonic way, using the in operator:
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