如何计算给定子字符串在Python字符串中出现的次数?
例如:
>>> 'foo bar foo'.numberOfOccurrences('foo')
2
若要获取子字符串的索引,请参见如何查找子字符串的所有出现?。
如何计算给定子字符串在Python字符串中出现的次数?
例如:
>>> 'foo bar foo'.numberOfOccurrences('foo')
2
若要获取子字符串的索引,请参见如何查找子字符串的所有出现?。
当前回答
下面的逻辑将适用于所有字符串和特殊字符
def cnt_substr(inp_str, sub_str):
inp_join_str = ''.join(inp_str.split())
sub_join_str = ''.join(sub_str.split())
return inp_join_str.count(sub_join_str)
print(cnt_substr("the sky is $blue and not greenthe sky is $blue and not green", "the sky"))
其他回答
def count_substring(string, sub_string):
inc = 0
for i in range(0, len(string)):
slice_object = slice(i,len(sub_string)+i)
count = len(string[slice_object])
if(count == len(sub_string)):
if(sub_string == string[slice_object]):
inc = inc + 1
return inc
if __name__ == '__main__':
string = input().strip()
sub_string = input().strip()
count = count_substring(string, sub_string)
print(count)
对于重叠计数,我们可以使用use:
def count_substring(string, sub_string):
count=0
beg=0
while(string.find(sub_string,beg)!=-1) :
count=count+1
beg=string.find(sub_string,beg)
beg=beg+1
return count
对于非重叠的情况,我们可以使用count()函数:
string.count(sub_string)
这里有一个解决方案,适用于非重叠和重叠的情况。为了澄清:重叠子字符串是指其最后一个字符与其第一个字符相同的子字符串。
def substr_count(st, sub):
# If a non-overlapping substring then just
# use the standard string `count` method
# to count the substring occurences
if sub[0] != sub[-1]:
return st.count(sub)
# Otherwise, create a copy of the source string,
# and starting from the index of the first occurence
# of the substring, adjust the source string to start
# from subsequent occurences of the substring and keep
# keep count of these occurences
_st = st[::]
start = _st.index(sub)
cnt = 0
while start is not None:
cnt += 1
try:
_st = _st[start + len(sub) - 1:]
start = _st.index(sub)
except (ValueError, IndexError):
return cnt
return cnt
s = 'arunununghhjj'
sb = 'nun'
results = 0
sub_len = len(sb)
for i in range(len(s)):
if s[i:i+sub_len] == sb:
results += 1
print results
根据你的真正意思,我提出以下解决方案:
你的意思是一个空格分隔子字符串的列表,并想知道所有子字符串中的子字符串位置编号是什么: S = 'sub1 sub2 sub3' s.split () .index(“sub2”) > > > 1 你的意思是子字符串在字符串中的char-position: s.find(“sub2”) > > > 5 你的意思是su-bstring的(非重叠)外观计数: s.count(“sub2”) > > > 1 s.count(“子”) > > > 3