计算多少个单词具有相同的开始和结束字母/ Python

Question

QUESTION : The variable sentence stores a string. Write code to determine how many words in sentence start and end with the same letter, including one-letter words. Store the result in the variable same_letter_count.

I've tweaked this a few different ways but I still can't figure it out. Any help + explanation is appreciated so I know how to handle this the next time.

sentence = "students flock to the arb for a variety of outdoor activities 
such as jogging and picnicking"

same_letter_count = 0
sentence_split = sentence.split(' ')
sent_length = len(sentence_split)
#print(sent_length)
# Write your code here.
for d in sentence_split:
    #print(d[0])
    if d[0] == d:
        same_letter_count = same_letter_count + 1
    elif d[-1] == d:
        same_letter_count = same_letter_count + 1
print(same_letter_count)

I'm getting an answer of 1, the correct answer is 2.

Answer 1

You can take advantage of the fact the Python's booleans can be treated like zeros and ones and just add up all the boolean values of the test word[0] == word[-1] . The expression:

[w[0] == w[-1] for w in sentence.split()] 

evaluates to a list like [True, False, False...] . Taking the sum of that is the same as counting the number of True values and is a very typical way of doing something like this in Python.

sentence = "students flock to the arb for a variety of outdoor activities such as jogging and picnicking"
same_letter_count = sum(w[0] == w[-1] for w in sentence.split())
# 2

Answer 2

if d[0] == d:
    same_letter_count = same_letter_count + 1
elif d[-1] == d:
    same_letter_count = same_letter_count + 1

This checks if the first letter is equal to the entire word, or if the last letter is equal to the entire word. Therefore you are only counting "a". Instead try

if d[0] == d[-1]:
    same_letter_count = same_letter_count + 1

Answer 3

A quick solution by pandas :

s = pd.Series(sentence.split(' '))
(s.str[0] == s.str[-1]).sum()

gives answer 2 .

You can even get those words:

s[s.str[0] == s.str[-1]]

gives:

0    students
6           a
dtype: object

Answer 4

sentence = "students flock to the arb for a variety of outdoor activities such as jogging and picnicking"
same_letter_count = 0

sentence_split = sentence.split(' ')
sentense_length = len(sentence_split)

for d in sentence_split:
    if d[0] == d[-1]:
        same_letter_count += 1
print(same_letter_count)