Index error, code not splitting my string properly-CodePudding

I am trying to run pytest to test my function but I am running into an issue where I am trying to split a function called get_prepositional_phrase(amount) that returns a string of three variables into each variable but after I split it I keep getting a list index out of range error

my code for the string I am trying to split is:

phrase = (f'{connect} {determiner2} {noun2}')

my code is below for the test function.

def test_get_prepositional_phrase():
    phrase1 = get_prepositional_phrase(1)

prep = ["about", "above", "across", "after", "along",
    "around", "at", "before", "behind", "below",
    "beyond", "by", "despite", "except", "for",
    "from", "in", "into", "near", "of",
    "off", "on", "onto", "out", "over",
    "past", "to", "under", "with", "without"]


for word in phrase1:
    parts = word.split()
    one = parts[0]
    # two = parts[1]
    # three = parts[2]

for _ in range(30):
    connector = get_preposition()
assert one in connector

CodePudding user response：

Line 115 will raise an exception if the parts list has only one (or zero) items in it. Given your code is

one = parts[1]
# two = parts[1]
# three = parts[2]

I would say that you should be assigning parts[0], rather than parts[1], to one. Additionally, a good rule to follow is to check all required pre-conditions first. That would involve:

assert type(phrase1) is list                   # Is list.
assert len(phrase1) >= 2                       # Minimum size.
assert(all([type(x) is str for x in phrase1])) # All items are string.
for word in phrase1:
    pass # Guaranteed safe to use word[1] as a string here.

In any case, the fact that your phrase is constructed as:

f'{connect} {determiner2} {noun2}'

means that it is a single string rather than a list of words. That means that:

for word in phrase1:      # One character at a time.
    parts = word.split()  # One-element list with that character.
    one = parts[1]        # NO !

will always give you a single-character string in word and therefore parts will always be a one-element list containing that one-character string. Hence the parts[1] expression will fail.

What you need instead is the following:

for word in phrase1.split(): # One word at a time.
    one = word[0]
    # two = word[1]
    # three = word[2]

Bottom line: for i in a_string gives you each character of the string while for i in a_list_of_strings gives you each string in the list.