Python built-in function locals

Python built-in functions locals English document:

Locals ()

Update and return a dictionary representing the current local symbol table. Free variables are returned by locals () when it is called in function blocks, but not in class blocks.

Note:

1. the function returns a dictionary composed of local variables and their values in the current scope, similar to the globals function (returning global variables)

>>> Locals () {'_ package _': None, '_ loader __':
 
  
, '_ Doc _': None, '_ name _': '_ main _', '_ builtins __':
  
   
, '_ Spec _': None }>>> a = 1 >>> locals () # an additional item {'_ package _': None, '_ loader _' with a key of 1 is added __':
   
    
, 'A': 1, '_ doc _': None, '_ name _': '_ main __', '_ builtins __':
    
     
, '_ Spec _': None}
    
   
  
 

2. it can be used in functions.

>>> Def f (): print ('before define a') print (locals () # no variable a = 1 print ('After define a') in the scope ') print (locals () # There is a variable a in the scope. The value is 1 >>> f
 
  
>>> F () before define a {} after define a {'a': 1}
 

3. the returned dictionary set cannot be modified.

>>> Def f (): print ('before define a') print (locals () # no variable a = 1 print ('After define a') in the scope ') print (locals () # There is a variable a in the scope. The value is 1 B = locals () print ('B ["a"]:', B ['A']) B ['A'] = 2 # modify B ['A'] value print ('change locals value ') print ('B ["a"]:', B ['A']) print ('A', a) # The value of a has not changed >>> f () before define a {} after define a {'a': 1} B ["a"]: 1 change locals valueb ["a"]: 2a is 1 >>>