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My script returns no values
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My script returns no values
#1
Hi,

I have just started doing the google python course online and am completing my first assignment by running the string1.py script. I have tested my little routines in the python interpreter and they work there, by when i actually run the string1.py script the test routines tell me they got nothing returned from my code. I am running on a Windows 10 machine at the command line. Python 2.7..

Here is my script, please point me in the right direction, thanks:

#! python
# Copyright 2010 Google Inc.
# Licensed under the Apache License, Version 2.0
# http://www.apache.org/licenses/LICENSE-2.0

# Google's Python Class
# http://code.google.com/edu/languages/goo...hon-class/

# Basic string exercises
# Fill in the code for the functions below. main() is already set up
# to call the functions with a few different inputs,
# printing 'OK' when each function is correct.
# The starter code for each function includes a 'return'
# which is just a placeholder for your code.
# It's ok if you do not complete all the functions, and there
# are some additional functions to try in string2.py.


# A. donuts
# Given an int count of a number of donuts, return a string
# of the form 'Number of donuts: <count>', where <count> is the number
# passed in. However, if the count is 10 or more, then use the word 'many'
# instead of the actual count.
# So donuts(5) returns 'Number of donuts: 5'
# and donuts(23) returns 'Number of donuts: many'
def donuts(count):
p = count
if p <= 9:
print 'Number of donuts:', p
elif p >= 10:
print 'Number of donuts:', 'many'



# B. both_ends
# Given a string s, return a string made of the first 2
# and the last 2 chars of the original string,
# so 'spring' yields 'spng'. However, if the string length
# is less than 2, return instead the empty string.
def both_ends(s):
if len(s) >= 2:
p = s[:2] + s[-2:]
print p
elif len(s) < 1:
print s



# C. fix_start
# Given a string s, return a string
# where all occurences of its first char have
# been changed to '*', except do not change
# the first char itself.
# e.g. 'babble' yields 'ba**le'
# Assume that the string is length 1 or more.
# Hint: s.replace(stra, strb) returns a version of string s
# where all instances of stra have been replaced by strb.
def fix_start(s):
# +++your code here+++
if len(s) >= 1:
r = s[1:]
p = s[:1]
p = p + r.replace(p, '*')
print p


# D. MixUp
# Given strings a and b, return a single string with a and b separated
# by a space '<a> <b>', except swap the first 2 chars of each string.
# e.g.
# 'mix', pod' -> 'pox mid'
# 'dog', 'dinner' -> 'dig donner'
# Assume a and b are length 2 or more.
def mix_up(a, b):
# +++your code here+++
if len(a) >= 2 and len(b) >= 2:
p = a[:2]
r = b[:2]
print r + a[2:], p + b[2:]


# Provided simple test() function used in main() to print
# what each function returns vs. what it's supposed to return.
def test(got, expected):
if got == expected:
prefix = ' OK '
else:
prefix = ' X '
print '%s got: %s expected: %s' % (prefix, repr(got), repr(expected))


# Provided main() calls the above functions with interesting inputs,
# using test() to check if each result is correct or not.
def main():
print 'donuts'
# Each line calls donuts, compares its result to the expected for that call.
test(donuts(4), 'Number of donuts: 4')
test(donuts(9), 'Number of donuts: 9')
test(donuts(10), 'Number of donuts: many')
test(donuts(99), 'Number of donuts: many')

print
print 'both_ends'
test(both_ends('spring'), 'spng')
test(both_ends('Hello'), 'Helo')
test(both_ends('a'), '')
test(both_ends('xyz'), 'xyyz')


print
print 'fix_start'
test(fix_start('babble'), 'ba**le')
test(fix_start('aardvark'), 'a*rdv*rk')
test(fix_start('google'), 'goo*le')
test(fix_start('donut'), 'donut')

print
print 'mix_up'
test(mix_up('mix', 'pod'), 'pox mid')
test(mix_up('dog', 'dinner'), 'dig donner')
test(mix_up('gnash', 'sport'), 'spash gnort')
test(mix_up('pezzy', 'firm'), 'fizzy perm')


# Standard boilerplate to call the main() function.
if __name__ == '__main__':
main()
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#2
Here is the output from one of the test routines:

donuts
Number of donuts: 4
X got: None expected: 'Number of donuts: 4'
Number of donuts: 9
X got: None expected: 'Number of donuts: 9'
Number of donuts: many
X got: None expected: 'Number of donuts: many'
Number of donuts: many
X got: None expected: 'Number of donuts: many'
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#3
Here is how I tested in the interpreter:

>>> p = 5
>>> if p <= 9:
... print 'Number of donuts:', p
... elif p >= 10:
... print 'Number of donuts:', 'many'
...
Number of donuts: 5
>>> p = 59
>>> if p <= 9:
... print 'Number of donuts:', p
... elif p >= 10:
... print 'Number of donuts:', 'many'
...
Number of donuts: many
>
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#4
Your code should return a string, not print a string. Replace the print statements in donuts(), both_ends() fix_start() and mix_up() with code that creates and returns a string to be printed by test(). For example, donuts() should look like this:
def donuts(count):
    if count < 10:
        return 'Number of donuts: ' + str(count)
    return 'Number of donuts: many'
And when testing in the interpreter you should call main().
Output:
>>> main() donuts OK got: 'Number of donuts: 4' expected: 'Number of donuts: 4' OK got: 'Number of donuts: 9' expected: 'Number of donuts: 9' OK got: 'Number of donuts: many' expected: 'Number of donuts: many' OK got: 'Number of donuts: many' expected: 'Number of donuts: many' both_ends OK got: 'spng' expected: 'spng' OK got: 'Helo' expected: 'Helo' OK got: '' expected: '' OK got: 'xyyz' expected: 'xyyz' fix_start OK got: 'ba**le' expected: 'ba**le' OK got: 'a*rdv*rk' expected: 'a*rdv*rk' OK got: 'goo*le' expected: 'goo*le' OK got: 'donut' expected: 'donut' mix_up OK got: 'pox mid' expected: 'pox mid' OK got: 'dig donner' expected: 'dig donner' OK got: 'spash gnort' expected: 'spash gnort'
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#5
(Dec-04-2020, 02:22 PM)deanhystad Wrote: Your code should return a string, not print a string. Replace the print statements in donuts(), both_ends() fix_start() and mix_up() with code that creates and returns a string to be printed by test(). For example, donuts() should look like this:
def donuts(count):
    if count < 10:
        return 'Number of donuts: ' + str(count)
    return 'Number of donuts: many'
And when testing in the interpreter you should call main().
Output:
>>> main() donuts OK got: 'Number of donuts: 4' expected: 'Number of donuts: 4' OK got: 'Number of donuts: 9' expected: 'Number of donuts: 9' OK got: 'Number of donuts: many' expected: 'Number of donuts: many' OK got: 'Number of donuts: many' expected: 'Number of donuts: many' both_ends OK got: 'spng' expected: 'spng' OK got: 'Helo' expected: 'Helo' OK got: '' expected: '' OK got: 'xyyz' expected: 'xyyz' fix_start OK got: 'ba**le' expected: 'ba**le' OK got: 'a*rdv*rk' expected: 'a*rdv*rk' OK got: 'goo*le' expected: 'goo*le' OK got: 'donut' expected: 'donut' mix_up OK got: 'pox mid' expected: 'pox mid' OK got: 'dig donner' expected: 'dig donner' OK got: 'spash gnort' expected: 'spash gnort'
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#6
(Dec-04-2020, 02:22 PM)deanhystad Wrote: Your code should return a string, not print a string. Replace the print statements in donuts(), both_ends() fix_start() and mix_up() with code that creates and returns a string to be printed by test(). For example, donuts() should look like this:
def donuts(count):
    if count < 10:
        return 'Number of donuts: ' + str(count)
    return 'Number of donuts: many'
And when testing in the interpreter you should call main().
Output:
>>> main() donuts OK got: 'Number of donuts: 4' expected: 'Number of donuts: 4' OK got: 'Number of donuts: 9' expected: 'Number of donuts: 9' OK got: 'Number of donuts: many' expected: 'Number of donuts: many' OK got: 'Number of donuts: many' expected: 'Number of donuts: many' both_ends OK got: 'spng' expected: 'spng' OK got: 'Helo' expected: 'Helo' OK got: '' expected: '' OK got: 'xyyz' expected: 'xyyz' fix_start OK got: 'ba**le' expected: 'ba**le' OK got: 'a*rdv*rk' expected: 'a*rdv*rk' OK got: 'goo*le' expected: 'goo*le' OK got: 'donut' expected: 'donut' mix_up OK got: 'pox mid' expected: 'pox mid' OK got: 'dig donner' expected: 'dig donner' OK got: 'spash gnort' expected: 'spash gnort'

Thanks very much, all working well now, and for the extra tips..
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#7
I find it quite disturbing that Google for Education states:

Quote:For Google's Python Class, it's best to use Python 2.7. Although Python 3.x is becoming more popular, this course is designed for Python 2.6 or later.

Google is industry heavyweight but not everything is gold what shines. Do not take any course which insists on using Python 2. Why? Read official statement Sunsetting Python 2

Quote:We are volunteers who make and take care of the Python programming language. We have decided that January 1, 2020, was the day that we sunset Python 2. That means that we will not improve it anymore after that day, even if someone finds a security problem in it. You should upgrade to Python 3 as soon as you can.

It's not recommended to learn something obsolete. Why learn something you can't use?
ndc85430 likes this post
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Da Bishop: There's a dead bishop on the landing. I don't know who keeps bringing them in here. ....but society is to blame.
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#8
[quote="perfringo" pid='132461' dateline='1607093302']
I find it quite disturbing that Google for Education states:

[quote]For Google's Python Class, it's best to use Python 2.7. Although Python 3.x is becoming more popular, this course is designed for Python 2.6 or later.[/quote]

Google is industry heavyweight but not everything is gold what shines. Do not take any course which insists on using Python 2. Why? Read official statement Sunsetting Python 2

[quote]
We are volunteers who make and take care of the Python programming language. We have decided that January 1, 2020, was the day that we sunset Python 2. That means that we will not improve it anymore after that day, even if someone finds a security problem in it. You should upgrade to Python 3 as soon as you can.
[/quote]

It's not recommended to learn something obsolete. Why learn something you can't use?

I am an older guy, like the bottom up approach. Stepping up to version 3 will be easy. The standard of the Google course shines for me, interactive videos, lessons and exercises... Google does not shine but course material shines as a starting place... you can ask me about database programming, bash, little bit of powershell and all those things i already have... i will get to version 3... slowly catchy monkey.. Smile Wink
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