Related Articles

# Python | Ways to count number of substring in string

• Last Updated : 30 Jun, 2019

Given a string and a substring, write a Python program to find how many numbers of substring are there in the string (including overlapping cases). Let’s discuss a few methods below.

Method #1: Using `re.findall()`

 `# Python code to demonstrate ``# to count total number``# of substring in string`` ` `import` `re``# Initialising string``ini_str ``=` `"ababababa"``sub_str ``=` `'aba'`` ` `# Count count of substrings using re.findall``res ``=` `len``(re.findall(``'(?= aba)'``, ini_str))`` ` `# Printing result``print``(``"Number of substrings"``, res)`
Output:
```Number of substrings 0
```

Method #2: Using `re.finditer()`

 `# Python code to demonstrate ``# to count total number``# of substring in string`` ` `import` `re``# Initialising string``ini_str ``=` `"ababababa"``sub_str ``=` `'aba'`` ` `# Count count of substrings using re.finditer``res ``=` `sum``(``1` `for` `_ ``in` `re.finditer(``'(?= aba)'``, ini_str))`` ` `# Printing result``print``(``"Number of substrings"``, res)`
Output:

```Number of substrings 0
```

Method #3: Using `startswith()`

 `# Python code to demonstrate ``# to count total number``# of substring in string`` ` `# Initialising string``ini_str ``=` `"ababababa"``sub_str ``=` `'aba'`` ` `# Count count of substrings using startswith``res ``=` `sum``(``1` `for` `i ``in` `range``(``len``(ini_str)) ``         ``if` `ini_str.startswith(``"aba"``, i))`` ` `# Printing result``print``(``"Number of substrings"``, res)`
Output:
```Number of substrings 4
```

Attention geek! Strengthen your foundations with the Python Programming Foundation Course and learn the basics.

To begin with, your interview preparations Enhance your Data Structures concepts with the Python DS Course. And to begin with your Machine Learning Journey, join the Machine Learning – Basic Level Course

My Personal Notes arrow_drop_up