Let's say I have a method definition like this:
def myMethod(a, b, c, d, e)
Then, I have a variable and a tuple like this:
myVariable = 1
myTuple = (2, 3, 4, 5)
Is there a way I can pass explode the tuple so that I can pass its members as parameters? Something like this (although I know this won't work as the entire tuple is considered the second parameter):
myMethod(myVariable, myTuple)
I'd like to avoid referencing each tuple member individually if possible...
1) Using tuple() builtin function tuple () function can take any iterable as an argument and convert it into a tuple object. As you wish to convert a python list to a tuple, you can pass the entire list as a parameter within the tuple() function, and it will return the tuple data type as an output.
The most Pythonic way to convert a tuple to a list in Python is to call the built-in list() function and pass the tuple as a function argument to the function. The function list() takes any sequence type such as a tuple and converts them to lists. The return value of the function is the new list generated.
A tuple can also be passed as a single argument to the function. Individual tuples as arguments are just individual variables. A function call is not an assignment statement; it's a reference mapping.
To expand tuples into arguments with Python, we can use the * operator. to unpack the tuple (1, 2, 3) with * as the arguments of add . Therefore, a is 1, b is 2, and c is 3. And res is 6.
You are looking for the argument unpacking operator *
:
myMethod(myVariable, *myTuple)
From the Python documentation:
The reverse situation occurs when the arguments are already in a list or tuple but need to be unpacked for a function call requiring separate positional arguments. For instance, the built-in range() function expects separate start and stop arguments. If they are not available separately, write the function call with the *-operator to unpack the arguments out of a list or tuple:
>>> range(3, 6) # normal call with separate arguments
[3, 4, 5]
>>> args = [3, 6]
>>> range(*args) # call with arguments unpacked from a list
[3, 4, 5]
In the same fashion, dictionaries can deliver keyword arguments with the **-operator:
>>> def parrot(voltage, state='a stiff', action='voom'):
... print "-- This parrot wouldn't", action,
... print "if you put", voltage, "volts through it.",
... print "E's", state, "!"
...
>>> d = {"voltage": "four million", "state": "bleedin' demised", "action": "VOOM"}
>>> parrot(**d)
-- This parrot wouldn't VOOM if you put four million volts through it. E's bleedin' demised !
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