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
不使用Counter(), count和regex获得所有字符计数的另一种方法
counts_dict = {}
for c in list(sentence):
if c not in counts_dict:
counts_dict[c] = 0
counts_dict[c] += 1
for key, value in counts_dict.items():
print(key, value)
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
“不使用计数查找字符串中需要的字符”方法。
import re
def count(s, ch):
pass
def main():
s = raw_input ("Enter strings what you like, for example, 'welcome': ")
ch = raw_input ("Enter you want count characters, but best result to find one character: " )
print ( len (re.findall ( ch, s ) ) )
main()
使用数:
sentence = 'A man walked up to a door'
print(sentence.count('a'))
# 4
要查找句子中字符的出现情况,您可以使用下面的代码
首先,我从句子中取出了唯一的字符,然后我计算了每个字符在句子中的出现次数,其中包括空格的出现次数。
ab = set("Mary had a little lamb")
test_str = "Mary had a little lamb"
for i in ab:
counter = test_str.count(i)
if i == ' ':
i = 'Space'
print(counter, i)
以上代码的输出如下所示。
1 : r ,
1 : h ,
1 : e ,
1 : M ,
4 : a ,
1 : b ,
1 : d ,
2 : t ,
3 : l ,
1 : i ,
4 : Space ,
1 : y ,
1 : m ,
这个简单直接的函数可能会有帮助:
def check_freq(x):
freq = {}
for c in set(x):
freq[c] = x.count(c)
return freq
check_freq("abbabcbdbabdbdbabababcbcbab")
{'a': 7, 'b': 14, 'c': 3, 'd': 3}
如果需要理解:
def check_freq(x):
return {c: x.count(c) for c in set(x)}