如何计算字符串中字符出现的次数?
如。“a”在“Mary had a little lamb”中出现了4次。
如何计算字符串中字符出现的次数?
如。“a”在“Mary had a little lamb”中出现了4次。
当前回答
你可以使用循环和字典。
def count_letter(text):
result = {}
for letter in text:
if letter not in result:
result[letter] = 0
result[letter] += 1
return result
其他回答
要获得所有字母的计数,请使用集合。计数器:
>>> from collections import Counter
>>> counter = Counter("Mary had a little lamb")
>>> counter['a']
4
Str.count (sub[, start[, end]]) 返回子字符串sub在范围[start, end]中不重叠出现的次数。可选参数start和end被解释为片表示法。
>>> sentence = 'Mary had a little lamb'
>>> sentence.count('a')
4
我是pandas库的粉丝,尤其是value_counts()方法。你可以用它来计算字符串中每个字符的出现次数:
>>> import pandas as pd
>>> phrase = "I love the pandas library and its `value_counts()` method"
>>> pd.Series(list(phrase)).value_counts()
8
a 5
e 4
t 4
o 3
n 3
s 3
d 3
l 3
u 2
i 2
r 2
v 2
` 2
h 2
p 1
b 1
I 1
m 1
( 1
y 1
_ 1
) 1
c 1
dtype: int64
不超过这个IMHO -你可以添加上或下的方法
def count_letter_in_str(string,letter):
return string.count(letter)
a = "I walked today,"
c=['d','e','f']
count=0
for i in a:
if str(i) in c:
count+=1
print(count)