Using the same name for variables which are in different functions?

Question

I've been searching a while for my question but haven't found anything of use. My question is rather easy and straightforward.

Is it preferable or perhaps "pythonic" to use the same name for a certain variable which will appear in different functions, but with the same purpose?

For example:

def first_function():
    pt = win.getMouse() # This waits for a mouseclick in a graphical window.

    if blabla.button.clicked(pt):
        second_function()

def second_function():
    pt = win.getMouse() 

    if whatever.button.clicked(pt):
        third_function()

Does it matter if the variable reference (pt) to win.getMouse() in the second_function() has the same name as the variable in the first_function()? Or should the variable pt in the second function be named something else?

Only in the example provided (2 functions, equal scope) is this totally OK. Conversely: totally NOT OK if there's any overlapping scope (global, main vs function, or nested functions) and pylint will flag it with a warning. — Scott Prive
– Scott Prive, Commented Aug 23, 2022 at 3:52

Martijn Pieters · Accepted Answer · 2013-12-10 11:31:45Z

19

Names in functions are local; reuse them as you see fit!

In other words, the names in one function have no relationship to names in another function. Use good, readable variable names and don't worry about names clashing.

answered Dec 10, 2013 at 11:31

Martijn Pieters

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3 Comments

user2357112 Over a year ago

For example, there's no need to come up with a dozen variations on i or item for a dozen for loops in a dozen functions.

Bondenn Over a year ago

@MartijnPieters Okey thank you this answers my questions. I find the readability better if I'm using the same variable namefor all the variables refering to win.getMouse() in my program.

Martijn Pieters Over a year ago

Exactly; and the Zen of Python states that readability counts. Readability is Pythonic.

Lazybeem · Accepted Answer · 2013-12-10 11:34:15Z

2

Its not about "Pythonic" or not. In programming you always wish your variables to have a meaning, if the same name occures in differend functions that means they do things with the same purpose or same params. Its fine to use same names in different functions, as long as they don't collide and make problems

answered Dec 10, 2013 at 11:34

Lazybeem

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Comments

James Mills · Accepted Answer · 2013-12-10 11:39:52Z

1

Variables defined in a function have Function Scope and are only visible in the body of the function.

See: http://en.wikipedia.org/wiki/Scope_(computer_science)#Python for an explanation of Python's scoping rules.

edited Dec 10, 2013 at 11:39

answered Dec 10, 2013 at 11:34

James Mills

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