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
Python 3
有两种方法可以做到这一点:
1)内置函数count()
sentence = 'Mary had a little lamb'
print(sentence.count('a'))`
2)不使用函数
sentence = 'Mary had a little lamb'
count = 0
for i in sentence:
if i == "a":
count = count + 1
print(count)
其他回答
spam = 'have a nice day'
var = 'd'
def count(spam, var):
found = 0
for key in spam:
if key == var:
found += 1
return found
count(spam, var)
print 'count %s is: %s ' %(var, count(spam, var))
“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()
我不知道“最简单的”,但简单的理解可以做到:
>>> my_string = "Mary had a little lamb"
>>> sum(char == 'a' for char in my_string)
4
利用内置的和,生成器理解和bool是整数的子类的事实:如何乘字符等于'a'。
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)