find a string hackereank

1def count_substring(string, sub_string):
2    count=0  #initialise count variable
3    for i in range(0,len(string)):
4        if string[i:].startswith(sub_string): # basically it traverses from left to right and looks for occurence of substring
5            count+=1 #every time count will increase by 1
6
7    return count

1#(method 1)
2import re
3def count_substring(string,sub_string)
4count = re.findall('(?='+sub_string+')',string)
5return len(count)
6
7# (method 2) lengthy but easier for beginners
8def count_substring(string, sub_string): 
9    zero=0
10    astring=string + "@"
11    sub_count=0
12    count=0
13    for i in range (len(astring)-1):
14        if astring[i]==sub_string[0]:
15            for j in range(1,len(sub_string)):
16                if astring[i+j]==sub_string[j]:
17                    sub_count+=1
18                elif astring[j+i]=='@':
19                    break
20            if sub_count==len(sub_string)-1:
21                count+=1
22            sub_count=0
23    return count
24
25