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Question

Write a function file_in_english(filename, character_limit) that takes a filename (as a str) and a character_limit (as an int). The filename is the name of the file to convert from Cat Latin to English and the character limit is the maximum number of characters that can be converted. The limit is on the total number of characters in the output (including newline characters).

The function should return a string that contains all the converted lines in the same order as the file - remember the newline character at the end of each line (that is make sure you include a newline character at the end of each converted line so that it is included in the line's length).

If the limit is exceeded (ie, a converted sentence would take the output over the limit) then the sentence that takes the character count over the limit shouldn't be added to the output. A line with "<>" should be added at the end of the output instead. The processing of lines should then stop.

The lines in the file will each be a sentence in Weird Latin and your program should print out the English version of each sentence

The function should keep adding sentences until it runs out of input from the file or the total number of characters printed (including spaces) exceeds the limit.

The answer must include your definition of english_sentence and its helper(s) functions - that I should have called english_word or similar.

You MUST use while in your file_in_english function.

You can only use one return statement per function.

The test file used in the examples (test1.txt) has the following data:

impleseeoow estteeoow aseceeoow
impleseeoow estteeoow aseceeoow ineleeoow 2meeoow
impleseeoow estteeoow aseceeoow ineleeoow 3meeoow
impleseeoow estteeoow aseceeoow ineleeoow 4meeoow

I program works fine except that sometimes it returns None.

def english_sentence(sentence):
"""Reverse Translation"""
consonants = 'bcdfghjklmnpqrstvwxyzBCDFGHJKLMNPQRSTVWXYZ'
eng_sentence = [] 
for coded_word in sentence.split():
    if coded_word.endswith("eeoow") and (coded_word[-6] in consonants):
        english_word = coded_word[-6] + coded_word[:-6]
        if (coded_word[-6] == 'm') and (coded_word[0] not in consonants):
            english_word = '(' + english_word + ' or ' + coded_word[:-6] + ')'
    eng_sentence.append(english_word)
return " ".join(eng_sentence)


def file_in_english(filename, character_limit):
"""English File"""
newone = open(filename)
nowline = newone.readline()  
characters = 0
while characters < character_limit and nowline != "":
    process = nowline[0:-1]
    print(english_sentence(process))
    characters += len(nowline)
    nowline = newone.readline()
if characters > character_limit:
    return("<<Output limit exceeded>>")



ans = file_in_english('test1.txt', 20)
print(ans)

Output is:

simple test case
simple test case line (m2 or 2)
simple test case line (m3 or 3)
simple test case line (m4 or 4)
None

But I must use only one return statement in each function. How can I do that for the second function and avoid the "None" in output?

Answer 1

You're doing the same thing as:

def f():
    print('hello')
print(f())

So basically narrows down to:

print(print('hello world'))

Also btw:

>>> type(print('hello'))
hello
<class 'NoneType'>
>>> 

To solve your code do:

def file_in_english(filename, character_limit):
    s=""
    """English File"""
    newone = open(filename)
    nowline = newone.readline()  
    characters = 0
    while characters < character_limit and nowline != "":
        process = nowline[0:-1]
        s+=english_sentence(process)+'\n'
        characters += len(nowline)
        nowline = newone.readline()
    if characters > character_limit:
        s+="<<Output limit exceeded>>"

    return s


ans = file_in_english('test1.txt', 20)
print(ans)

Answer 2

You have to make sure, that any function that should return something, does this for ALL ways that your function can end.

Your function file_in_english only returns something for the case if characters > character_limit:

If charachter == or charachter < character_limit this is not the case, the function returns nothing explicitly.

Any function that does not return something from it on end, implicitly returns None when it returns to its caller.

def something(boolean):
    """Function that only returns something meaninfull if boolean is True."""
    if boolean:
        return "Wow" 

print(something(True))  # returns Wow
print(something(False)) # implicitly returns/prints None

You can find this fact fe in the python tutorial:

Coming from other languages, you might object that fib is not a function but a procedure since it doesn't return a value. In fact, even functions without a return statement do return a value, albeit a rather boring one. This value is called None (it's a built-in name). Writing the value None is normally suppressed by the interpreter if it would be the only value written. You can see it if you really want to using print():

Source: https://docs.python.org/3.7/tutorial/controlflow.html#defining-functions - just short after the 2nd green example box