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Python Python Basics (Retired) Putting the "Fun" Back in "Function" Functions

Task 2 of 3: Function to return string

My Summarize function does return a string when run in my external python editor, but not in the grader, I must be close...

def add_list (thelist): total = 0 for ivar in thelist: total = total + ivar return total add_list([1, 2, 3]) def summarize (alist): total = 0 for ivar in alist: total = total + ivar return 'The sum of', alist,'is',total,'.' summarize([1, 2, 3])

functions.py
# add_list([1, 2, 3]) should return 6
# summarize([1, 2, 3]) should return "The sum of [1, 2, 3] is 6."
# Note: both functions will only take *one* argument each.
def add_list (thelist):
    total = 0
    for ivar in thelist:
        total = total + ivar
    return total
add_list([1, 2, 3])
def summarize (alist):
    total = 0
    for ivar in alist:
        total = total + ivar
    return 'The sum of', alist,'is',total,','
summarize([1, 2, 3])

1 Answer

Gunhoo Yoon
Gunhoo Yoon
5,027 Points

Update:

You can still read what I've wrote down there but this is probably the solution that you are best familiar with.

def summarize (alist):
    total = 0
    for ivar in alist:
        total = total + ivar
    return 'The sum of {} is {}.'.format(alist, total)

---------------------------Older-----------------------------------

return 'The sum of', alist,'is',total,','

#You get
#('The sum of', [1, 2, 3] 'is', 6 '.')  <- this is not a String.

I don' know how far you've learned but use this gimmick which you will learn anyways.

return "The sum of %s is %s." % (alist, total)
#or
return 'The sum of', str(alist), 'is', total, ','

First one create template string with placeholders which you can dynamically change. %s is a placeholder and % after String is operator that will try to connect values to your placeholder.

Second one explicitly tell we want string version of our list. This isn't much recommended though.

It is really weird question because when I tried the second method it passed which it shouldn't.

What you get from returning things like return 'hello', 'my', 'world' is ('hello', 'my', 'world') which is called tuple. This is not a string but somehow the grader accepts it.

Try running this code at the end of your code with Python interpreter.

print(type(summarize([1, 2, 3])) is str) #false
print(type(summarize([1, 2, 3])) is tuple) #true

This checks whether your result from summarize() is string or not.