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
使用数:
sentence = 'A man walked up to a door'
print(sentence.count('a'))
# 4
其他回答
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)}
正则表达式?
import re
my_string = "Mary had a little lamb"
len(re.findall("a", my_string))
a = "I walked today,"
c=['d','e','f']
count=0
for i in a:
if str(i) in c:
count+=1
print(count)
你可以使用.count():
>>> 'Mary had a little lamb'.count('a')
4
python - 3. x:
"aabc".count("a")
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。