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Python | Extract digits from given string
• Last Updated : 07 Jun, 2019

While programming, sometimes, we just require a certain type of data and need to discard other. This type of problem is quite common in Data Science domain, and since Data Science uses Python worldwide, its important to know how to extract specific elements. This article discusses certain ways in which only digit can be extracted. Let’s discuss the same.

Method #1 : Using `join() + isdigit() + filter()`

This task can be performed using the combination of above functions. The filter function filters the digits detected by the isdigit function and join function performs the task of reconstruction of join function.

 `# Python3 code to demonstrate``# Extract digit string ``# using join() + isdigit() + filter()`` ` `# initializing string``test_string ``=` `'g1eeks4geeks5'`` ` `# printing original strings  ``print``(``"The original string : "` `+` `test_string)`` ` `# using join() + isdigit() + filter()``# Extract digit string ``res ``=` `''.join(``filter``(``lambda` `i: i.isdigit(), test_string))``     ` `# print result``print``(``"The digits string is : "` `+` `str``(res))`
Output :
```The original string : g1eeks4geeks5
The digits string is : 145
```

Method #2 : Using `re`
The regular expressions can also be used to perform this particular task. We can define the digit type requirement, using “\D”, and only digits are extracted from the string.

 `# Python3 code to demonstrate``# Extract digit string ``# using re``import` `re`` ` `# initializing string``test_string ``=` `'g1eeks4geeks5'`` ` `# printing original strings  ``print``(``"The original string : "` `+` `test_string)`` ` `# using re``# Extract digit string ``res ``=` `re.sub(``"\D"``, "", test_string)``     ` `# print result``print``(``"The digits string is : "` `+` `str``(res))`
Output :
```The original string : g1eeks4geeks5
The digits string is : 145
```

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