Question

我必须定义一个名为letterCount的函数，其中它返回一个整数，表示函数中有一个字符串的次数。出于某种原因，它返回2，我应该返回7

def letterCount(text,collection):
    for collection in text:
        if collection in text:
           return len(collection) + 1
seuss = 'The cat in a hat came back'
letters = 'ac'
print(letterCount(seuss,letters))

Answer 1

也许你想要这个：

def letterCount(text,collection):
    res = 0
    for c in text:
        if c in collection:
            res = res + 1
    return res
seuss = 'The cat in a hat came back'
letters = 'ac'
print(letterCount(seuss,letters))

您在collection中定义变量for collection in text:，它将变量隐藏在def letterCount(text,collection)中。

Answer 2

如果您想计算字符letters在seuss中出现的次数：

def letterCount(text,collection):
    count = 0

    for i in range(0, len(text) - len(collection)):
        if collection == text[i:i + len(collection)]:
            count += 1

    return count

seuss = 'The cat in a hat came back'
letters = 'ac'
print(letterCount(seuss,letters))

如果您想计算letters中seuss中每封字母的出现次数：

def letterCount(text,collection):
    count = 0

    for i in range(0, len(text)):
        for c in collection:       
            if c == text[i]:
                count += 1

    return count

seuss = 'The cat in a hat came back'
letters = 'ac'
print(letterCount(seuss,letters))

Answer 3

我认为你编写的python代码的语法是错误的。这很可能是你想要的

def letterCount(text,collection):
  for collection in text:
    if collection in text:
        return len(collection) + 1
seuss = 'The cat in a hat came back'
Letters = 'ac'
print(letterCount(seuss,Letters))

你的问题也不清楚。你能详细说明吗？如果您想要的是计算字符串中的单词数这就足够了

print len(seuss.split(' '))

Answer 4

假设您要计算句子中的字母数，我会这样做：

def letterCount(text,collection):
  lettercount = 0
  for letter in collection:
    lettercount += text.count(letter)
  return lettercount


seuss = 'The cat in a hat came back'
Letters = 'ac'
print(letterCount(seuss,Letters)) # Returns 8

说明：

lettercount = 0将我们的计数器设为0

for letter in collection:在传递给函数的字母列表中创建一个循环。在这种情况下，“a”和“c”

lettercount += text.count(letter)计算每个字母出现在句子中的次数，并将其添加到计数器中。

return lettercount将结果发回。

Answer 5

试试这个：

import re
def letterCount(text,collection):
    return sum(len(re.findall(c, text)) for c in collection)

# re.findall(c, text) -> find all occurences of letter c in text
# len(...)            -> get the length of the list of all occurrences of c in text
# sum(...)            -> sum up all the partial results

Answer 6

如果你想知道'a'或'c'进来的次数'戴着帽子的猫回来了'，那么：

import collections
def letter_count(text, letters):
    counter = collections.Counter(text)
    return sum(counter.get(letter, 0) for letter in letters)

Python计数字符串

6 个答案: