Local Variables¶
Variables defined in the main body of a script are called global variables. These variables are accessible inside of functions:
x = 5
def get_x():
return x
get_x()
5
The arguments parsed into and the variables defined inside the function are local variables. They only exist in a particular instance of a function. <!— namespace —>
In other words, these variables are not accessable from outside the function. For example:
def make_var():
func_var = 4
return func_var
make_var()
4
func_var
---------------------------------------------------------------------------
NameError Traceback (most recent call last)
<ipython-input-5-96e608aeebf3> in <module>
----> 1 func_var
NameError: name 'func_var' is not defined
If we were to define func_var as a global variable, make_var will instance a local variable instead of reassigning the global variable:
func_var = 6
print('Before function', func_var)
print('Function return', make_var())
print('After function', func_var)
Before function 6
Function return 4
After function 6
Note that when referencing a variable, Python will check the local namespace before the global namespace (i.e. local variables are given preference).
As stated above, function arguments can also be treated as local variables.
def arg_var(x):
return x
x = 5
arg_var(2)
2