python - 想要查找特定字符在特定句子中出现的次数

Question

代码

sentence = input("Please enter a sentence:")
character = input("Please enter a single character:")

counter = 0

1. 使用while循环:

while len(character) > 1:
      character = input("Please try again, enter a single character:")

我的问题是 if 语句对我不起作用。

while len(sentence) > counter:
    if sentence[0].__contains__(character):
        counter += 1
        print(counter)
    if sentence[1].__contains__(character):
        counter += 1
        print(counter)
    if sentence[3].__contains__(character):
        counter += 1
        print(counter)
    if sentence[4].__contains__(character):
        counter += 1
        print(counter)
    if sentence[5].__contains__(character):
        counter += 1
        print(counter)
    if sentence[6].__contains__(character):
        counter += 1
        print(counter)
    if sentence[7].__contains__(character):
        counter += 1
        print(counter)

主要问题是用户输入的句子是否大于或小于代码未采用的“if 语句”数量

Answer 1

使用 Counter :

from collections import Counter

sentence = input("Please enter a sentence:")
character = input("Please enter a single character:")

letter_cnts = Counter(sentence)

# Using format
print('Your character {cha} occurs {cnt} times in the sentence'.format(cha=character, cnt=letter_cnts[character]))

# Using f-strings
print(f'Your character "{character}" occurs {letter_cnts[character]} times in the sentence')