Python dict get or none

Get a default value from a Python dictionary if key is not present

Solution 3: The problem is that Python does not recognize an empty string as True. However, since it exists, it will provide a return. Solution 2: The «test» key in the response is acceptable because it exists and contains a value.

What is the scenario of dict.get(‘..’, None) or None?

By implementing this measure, any false value present in the dictionary (such as None , » , 0 , False , [] ) will be transformed into None . This effectively means that if the dictionary previously contained any of the aforementioned false values, they will now be replaced with None .

d.get('title', None) # False d.get('title', None) or None # None 

The practicality of this remains a topic of debate, but there is certainly a nuanced distinction to consider.

It is important to mention that this can be made simpler as follows:

In the absence of any element, d.get will return None by default.

In case you receive a message with a false-y value, it will be converted to None.

message = message.get('title', None) >> '' message.get('title', None) or None >> None 

In Python, if message.get(‘title’, None) or None results in an empty string, None will be returned. This is because an empty string has a boolean value of False .

In case any value other than False is returned by the dict evaluation, it will be replaced with None .

It is worth noting that the code could be improved by using message.get(‘title’) or None instead of dict.get . This is because dict.get will return None (the second argument) by default.

Dict.get(None) on a dict with None value takes default arg, def func( ; def foo( ; in · », ; None return func(a) ; a · if a

Python dict.get() or None scenario [duplicate]

The presence of or None is unnecessary as dict.get automatically returns None if the provided key is not found in the dictionary.

In such situations, it is recommended to refer to the documentation.

get(key[, default])

If the dictionary contains the specified key, its corresponding value will be returned. Otherwise, the default value will be returned, which defaults to None if not specified. This ensures that the method will not raise a KeyError.

Utilizing the second parameter of the «get» function is a straightforward method.

The default value for the second argument is used when the key is not found. In this case, the «or» operator selects the value before it if it exists, and chooses the value after it if the former is absent.

The problem lies in the fact that in Python, the empty string is not evaluated as True. To illustrate this, consider the following code snippet.

>>> x = 1 if "" else 0 >>> y = 1 if True else 0 >>> z = 1 if False else 0 

The values of x and z will both be 0, whereas the value of y will be 1.

dict.get() returns None by default 

or by using a defaultdict

Is there shorthand for returning a default value if None in Python?, Note that this also returns «default» if x is any falsy value, including an empty list, 0, empty string, or even datetime.time(0) (midnight).

Dict: get() not returning 0 if dict value contains None

It is not necessary for the code to return None if the test key exists in the ex_dict dictionary. Instead, it should only return 0 when the key is not found in the dictionary.

ex_dict = print type(ex_dict.get('test', 0)) # , 'test' exist, return None print(ex_dict.get('hello', 0)) # prints 0, 'hello' isn't a key inside ex_dict 

The response in ex_dict.get(‘test’, 0) is satisfactory as the «test» key has a value of None . When attempted with ex_dict.get(«non_existing_key», 0) , the response returns 0.

Python — Get default value if key has falsy value in dict, It is pythonic; the alternative, if you want it to happen automatically, is to subclass dict and implement getitem. · 2 · Thanks @Blckknght, but

Python dictionary .get() method with default value throws exception even when it should not even be executed

The problem with get is that it has a default value requiring build/evaluation, leading to the execution of the code even when unnecessary. This can potentially slow down the code and cause unnecessary errors to occur.

port.get(server_name) or default() 

In case the key is not found, get would return None and activate or default() . However, if get returns a value, default() won’t be called due to short-circuiting.

In the unlikely event that get returns a value that evaluates to «falsy», such as an empty string or zero, it could fail. However, since it is returning a server name in your case, I assume that this scenario is not possible.

By invoking the function, either through default() or default , it will execute. Refraining from calling it, as in the case of .get(. default) , would only yield the function object, which would not be suitable for your needs.

To invoke it exclusively when the key is absent, additional explanation is required. At this juncture, it is advisable to restructure the code.

ports = < "server1": 2222, "server2": 2223, "server3": 2224, >def get_port(server_name): port = ports.get(server_name) if not port: cursor.execute( "SELECT port FROM table WHERE server=%s LIMIT 1", (server_name,), ) port = cursor.fetchone()[0] return port 

The solution to your current problem/question can be found in the previous answer.

The initial evaluation is being conducted on default() .

I aim to provide additional details that would aid in comprehending the situation. Although it may seem like a basic inquiry, it pertains to crucial elements of Python (as well as other programming languages). It is my hope that this will capture the attention of some of our readers.

One aspect that is often misunderstood is Python’s eagerness in evaluation. A helpful post has been written on this topic.

Afterward, learn about the get() function and its ability to return a value, which might be a function as functions are first class objects in python.

Python 3 — dictionary get() Method, Python 3 — dictionary get() Method, The method get() returns a value for the given key. If key is not available then returns default value None.

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Python dict.get() or None scenario

You don’t need or None at all. dict.get returns None by default when it can’t find the provided key in the dictionary.

It’s a good idea to consult the documentation in these cases:

get(key[, default])

Return the value for key if key is in the dictionary, else default. If default is not given, it defaults to None, so that this method never raises a KeyError.

The issue is that the empty string is not considered True in python. for example take a look at this code.

>>> x = 1 if "" else 0 >>> y = 1 if True else 0 >>> z = 1 if False else 0 

The value of x and z will be 0 while the value for y will be 1.

dict.get() returns None by default 

Jules 973

You can simply use the second argument of get.

The second argument is the default for when it can’t find the key. The or in that case takes the thing before the or if it is something, otherwise takes whatever is after the or.

Matthias Schreiber 2117

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