Checking a variable against a list and seeing if a word in that list starts with the variable

Question

I'm trying to write a function that uses a checker that could be any length and checks it against the list. It should be case insensitive when checking and print the word. Example below

Input= startsWith('a',['apple','ApPle','orange','Apple','kiwi','apricot'])

Output:

apple
ApPle 
Apple 
apricot

But, it prints every string in the list all in lower case.

def startsWith(checker,lister):

    checker.lower()
    size = len(lister)
    i=0
    checklength = len(checker)
    lister = [element.lower() for element in lister]
    while(i<size):
        checkinlist = lister[i]
        if(checkinlist[0:checklength-1] in checker):
            # this is just to test to see if the variables are what i need
            # once the if statement works just append them to a new list
            # and print that
            print(lister[i])

        i=i+1

I get `NameError: name 'checker' is not defined`, when I run your script. — tommy.carstensen, Oct 06 '16 at 02:38
@tommy.carstensen thats because you didn't include the function definition, which is not properly formatted in the question at the moment. — GreenAsJade, Oct 06 '16 at 02:40
Although it is now formatted correctly, what is your actual question? — GreenAsJade, Oct 06 '16 at 02:42
lister contains only lowercase strings when you print it. What are you confused about? — OneCricketeer, Oct 06 '16 at 02:49

score 1 · Answer 1 · edited May 23 '17 at 10:29

Here's the root of the problem

lister = [element.lower() for element in lister]

lister now only contains lowercase strings, which you then print. You need to delay the lower() until you check for checker.

No need to check the length of anything. You can use filter

def startsWith(checker, lister):
    return list(filter(lambda x: x.lower().startswith(checker.lower()), lister))

for x in startsWith('a',['apple','ApPle','orange','Apple','kiwi','apricot']):
    print(x)

Output

apple
ApPle
Apple
apricot

Maddy · Accepted Answer · 2016-10-06T02:54:57.537

0

def startsWith(checker,lister):

    for i in range(len(lister)):
        words = lister[i].lower()
        if(words.startswith(checker)):
            print(lister[i])

def main():
    startsWith('a',['apple','ApPle','orange','Apple','kiwi','apricot'])
main()

OUTPUT

apple
ApPle
Apple
apricot
>>>

edited Oct 06 '16 at 02:54

answered Oct 06 '16 at 02:45

Maddy

2,025
5
26
59

Paul Rooney · Answer 3 · 2016-10-06T03:16:45.077

You should not mutate the original elements of lister, rather do the comparison on a new copy of those elements that has been converted to lower case.

It can be done in a single list comprehension.

def startsWith(checker, lister):
    cl = checker.lower()
    return [s for s in lister if s.lower().startswith(cl)]

Input= startsWith('a',['apple','ApPle','orange','Apple','kiwi','apricot'])

for i in Input:
    print(i)

Output:

apple
ApPle
Apple
apricot

Checking a variable against a list and seeing if a word in that list starts with the variable

3 Answers3