CODEWITHSUNDEEP
pythonpython-3.x
Maverick
Maverick

Reputation: 49

Python3 - Passing a list to a function

In Python 3, I'm currently trying to modify a list using a function. (By the way, VERY new to Python :) )

I'll show the directions for the problem, just as reference.

"Write a function called make_great() that modifies the list of magicians by adding the phrase 'the Great' to each magician's name. Call show_magicians() to see that the list has actually been modified."

magicians = ['larry', 'mo', 'curly', 'nate']

def printing_magicians(names):
    """Printing the magicians names"""
    for name in names:
        print(name.title())

printing_magicians(magicians)

def make_great(names):
    """Adding 'the Great' to each magician"""
    for name in names:
        print(names + " the Great")

I'm not sure where to go from here. I don't understand what argument to call for the make_great() function, and then I don't understand how to apply a show_magicians() function to see the list that has been modified. Any help would be awesome! Thanks in advance.

Upvotes: 0

Views: 2672

Answers (5)

Banghua Zhao
Banghua Zhao

Reputation: 1556

Here is the method in one line. The basic idea is to use list comprehension and modify all the elements of the list by slicing [:]. 

def make_great(names):
    """Adding 'the Great' to each magician"""
    names[:] = [name + ' the Great' for name in names]

The show_magicians function is to just print magicians since magicians variable is in the global scope.

def show_magicians():
    print(magicians)

Example:

>>> make_great(magicians)
>>> show_magicians()
['larry the Great', 'mo the Great', 'curly the Great', 'nate the Great']

Upvotes: 1

alpharoz
alpharoz

Reputation: 159

You could also do something like this with newNames defined globally:

newNames = []
def make_great(names):
    for name in names:
        name += " the Great"
        newNames.append(name)

Then you can go ahead and print your new list by calling your function with newNames as your argument.

Upvotes: 0

Mark
Mark

Reputation: 92440

It's idiomatic in Python to loop over lists with enumerate() when you need the index. It will give you both the value and in the index into the list so you can:

def make_great(names):
    for i, name in enumerate(names):
        names[i] = f'{name} the Great'

Upvotes: 1

blhsing
blhsing

Reputation: 106598

To modify a list in-place, you should reference each item of the list by its index:

def make_great(names):
    for i in range(len(names)):
        names[i] += " the Great"

Upvotes: 3

Axel Puig
Axel Puig

Reputation: 1334

If you want the make_great function to return the list you want, you can do:

def make_great(names):
    return [name + " the Great" for name in names]

Upvotes: -1

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