Isn't there a default value in the dictionary?

I want to return the default value when a value that is not in the dictionary is entered.

I don't know the exact name of the default value, but if you put = after the argument, it will use that value when the function argument is not given.

Function default arguments


def func(arg1):
	print(arg1)

 # $ func()   #Causes an error with no arguments
 # [Out]
 # ---------------------------------------------------------------------------
 # TypeError                                 Traceback (most recent call last)
 # <ipython-input-6-08a2da4138f6> in <module>()
 # ----> 1 func()

 # TypeError: func() missing 1 required positional argument: 'arg1'


def func(arg1=0):   #If there is a default argument, it will automatically use the default argument even if there is no argument
	print(arg1)

 # $ func()
 # [Out] # 0

Like this default argument in the dictionary

  1. When a value without a key is entered
  2. Returns the specified value I want that.

In such a case, use the get method.

get method docstring

dict.get? Docstring: D.get(k[,d]) -> D[k] if k in D, else d. d defaults to None.

dict.get method


dic={'a':6,'b':4}
 # $ dic['a']
 # 6

 # $ dic['b']
 # 4

 # $ dic['c']   #Error if a value that is not in the key is entered
 # ---------------------------------------------------------------------------
 # KeyError                                  Traceback (most recent call last)
 # <ipython-input-11-0c3be353eb91> in <module>()
 # ----> 1 ic['c']

 # KeyError: 'c'

$ dic.get('c',0)   #In dic'c'The second argument is returned because there is no
 # [Out] # 0

Also, if the second argument is not specified for get, None is returned.

Reference: Return None if Dictionary key is not available

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