CODEWITHSUNDEEP
python
Gambit2007
Gambit2007

Reputation: 4014

Python - list comprehension

I have the following list:

fruits = ['apple', 'cherry', 'banana', 'lemon']

And using a list comprehension, i need to generate a list that contains the fruits (in uppercase) that contain the letter 'a', so apple and banana.

I tried using:

small=[s.upper() for s in fruits for c in s if c=='a']

But it gives me a result with duplicates:

['APPLE', 'BANNANA', 'BANNANA', 'BANNANA']

How can i fix that? Thanks!

Upvotes: 0

Views: 586

Answers (4)

bluebrother
bluebrother

Reputation: 8906

You have two for loops in there but you only need one. Also, you're checking only the first character for 'a', but from the text I understand that 'a' could appear anywhere in the input. Plus, while this is not the case in your example, I assume it should also work for input strings that are not all-lowercase (like 'Apple'), so you should lower() the string before comparing with 'a'.

[s.upper() for s in fruits if 'a' in s.lower()]

Upvotes: 1

zmbq
zmbq

Reputation: 39069

[fruit.upper() for fruit in fruits if 'a' in fruit]

List comprehension can be a bit hard to comprehend. In this case it should be read from the middle out. You loop over all fruits (yeah, I know...), filter only those with 'a's in them and then convert them to upper case.

Upvotes: 0

Akshat Mahajan
Akshat Mahajan

Reputation: 9856

[s.upper() for s in fruits if 'a' in s]

The reason your list comprehension doesn't work is because it expands to this:

result = []
for s in fruits:
     for c in s:
         if c == 'a':
             result.append(s.upper ())

This will go through every character in fruit and keep all those fruits that have an 'a' in them, in proportion to how often 'a' appears in each fruit.

Upvotes: 4

Karoly Horvath
Karoly Horvath

Reputation: 96326

[s.upper() for s in fruits if 'a' in s]

Upvotes: 5

Related Questions