Python function inside of a function

Question

I'm reading an exercise out of a Python book, here is what it says:

Modify do_twice so that it takes two arguments, a function object and a value, and calls the function twice, passing the value as an argument.

Write a more general version of print_spam, called print_twice, that takes a string as a parameter and prints it twice.

Use the modified version of do_twice to call print_twice twice, passing 'spam' as an argument.

Heres what I wrote:

def do_twice(f, g):
    f(g)
    f(g)

def print_spam(s):
    print (s)

do_twice(print_spam('lol'))

What is the way it is supposed to be written? I'm totally stumped on this one.

root · Accepted Answer · 2013-01-17 22:07:01Z

7

Just give the string as a second argument to do_twice. The do_twice functions calls the print_spam and supplies the string as an argument:

def do_twice(f, g):
    f(g)
    f(g)

def print_spam(s):
    print (s)

do_twice(print_spam,'lol')

prints:

lol
lol

answered Jan 17, 2013 at 22:07

root

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Comments

beoliver · Accepted Answer · 2013-01-17 22:49:57Z

1

If for some reason you wanted to repeat the function n amount of times, you could also write something like this...

def do_n(f,g,n):
    for i in range(n):
        f(g)

do_n(print_spam,'lol',5)

lol
lol
lol
lol
lol

answered Jan 17, 2013 at 22:49

beoliver

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Comments

jkalden · Accepted Answer · 2016-01-18 14:03:13Z

0

def do_twice(func, arg):
    """Runs a function twice.

    func: function object
    arg: argument passed to the function
    """
    func(arg)
    func(arg)


def print_twice(arg):
    """Prints the argument twice.

    arg: anything printable
    """
    print(arg)
    print(arg)


def do_four(func, arg):
    """Runs a function four times.

    func: function object
    arg: argument passed to the function
    """
    do_twice(func, arg)
    do_twice(func, arg)


do_twice(print_twice, 'spam')
print('')

do_four(print_twice, 'spam')

edited Jan 18, 2016 at 14:03

jkalden

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answered Jan 18, 2016 at 13:23

brett berkeley

1

1 Comment

jkalden Over a year ago

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Jasmine kaur · Accepted Answer · 2021-09-20 00:34:53Z

0

In my opinion ,according to the question from book thinkpython it had four various parts and hence each part had different code snippet in regards to the instruction provided. The second part would have print_twice as function not print_spam . Also in third part "spam" would be the argument provided not "lol". So you could try this instead. All the best.

Here is the code

def do_twice(f,g):
f(g) 
f(g)

def print_twice(s):
print(s)
print(s)

do_twice(print_twice,'spam')

def do_four(do_twice,g):
do_twice(g)
do_twice(g)

answered Sep 20, 2021 at 0:34

Jasmine kaur

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