Using startswith in lambda expression and filter function with Python

Question

I'm trying to find the words starting with character "s". I have a list of strings (seq) to check.

seq = ['soup','dog','salad','cat','great']

sseq = " ".join(seq)

filtered = lambda x: True if sseq.startswith('s') else False

filtered_list = filter(filtered, seq)

print('Words are:')
for a in filtered_list:
    print(a)

The output is:

Words are:
soup
dog
salad
cat
great

Where I see the entire list. How can I use lambda and filter() method to return the words starting with "s" ? Thank you

Why not just use a simple list comprehension? After all, Python is all about doing things simply. :-) — s3dev
– s3dev, Commented May 14, 2021 at 18:41
Why are you using sseq in the function, instead of x, the argument? Why are you creating sseq in the first place? — juanpa.arrivillaga
– juanpa.arrivillaga, Commented May 14, 2021 at 18:44
Also, as an aside, don't assign lambda expressions to a name. If you are going to do that, just use a full function definition — juanpa.arrivillaga
– juanpa.arrivillaga, Commented May 14, 2021 at 18:44

Sayse · Accepted Answer · 2021-05-14 18:43:24Z

5

Your filter lambda always just checks what your joined word starts with, not the letter you pass in.

filtered = lambda x: x.startswith('s')

answered May 14, 2021 at 18:43

Sayse

43.4k14 gold badges85 silver badges150 bronze badges

Sign up to request clarification or add additional context in comments.

Comments

Thavas Antonio · Accepted Answer · 2021-05-14 18:43:02Z

1

Try this.

seq = ['soup','dog','salad','cat','great']
result = list(filter(lambda x: (x[0] == 's'), seq)) 
print(result)

or

seq = ['soup','dog','salad','cat','great']
result = list(filter(lambda x: x.startswith('s'),seq))
print(result)

both output

['soup', 'salad']

answered May 14, 2021 at 18:43

Thavas Antonio

5,9091 gold badge19 silver badges51 bronze badges

Comments

Shivam Roy · Accepted Answer · 2021-05-14 18:54:03Z

0

This is another elegant method if you're okay with not using filter:

filtered_list = [x for x in seq if x.startswith('s')]
print('Words are: '+ " , ".join(filtered_list))

Output:

Words are: soup , salad

edited May 14, 2021 at 18:54

answered May 14, 2021 at 18:48

Shivam Roy

2,0713 gold badges12 silver badges25 bronze badges

Collectives™ on Stack Overflow

Using startswith in lambda expression and filter function with Python

3 Answers 3

Comments

Comments

Comments

Your Answer

Hot Network Questions

Collectives™ on Stack Overflow

3 Answers 3

Comments

Comments

Comments

Your Answer

Sign up or log in

Post as a guest

Related