Python Regex to extract maximum numeric value from a string.

In this tutorial, we will learn to extract maximum numeric value from a string. Here we will have a sequence of characters comprises of numbers and lowercase letters. The number in the string will seperated by lowercase letters.We need to extract a number with maximum value from the given string. We will do so using python regrex.

Python Regex also called REs or regular expressions is a module using which we can specify rules to set the possible strings to match. It is available in re module.

Look at the examples to understand the input and output format.

Input: 'ab12cd23f1gh123'

Output: 123

Input: '56g43fr5'

Output: 56

To find a number occurring most of the time, we will use the following approach.

We will use re.findall() method to get the list of numbers in the string. To extract the number using '\d+' expression . And find the maximum number from the list.

Approach: Using findall() and max() method

In this method, we will find the numbers within the input string using re.findall() method. Then we will cast the number into integer using map() and then use max() to find the maximum numeric value from the list.

Algorithm

Step1: Import re module

Step2: Define a regex expression of number.

Step3: Use the regex method to list out the number in the string.

Step4: Convert the number into integer using map() method.

Step5: Find the maximum numeric value using max()

Step6: Print the value.

Python Program 1

Here is the python program to find maximum numeric value from the string using regex.

# import module for regular expression and collections
import re
#input
string='ab12cd123ef23'
#seperate number from string
number = re.findall('\d+', string)
#convert it into integer
number = map(int, number)
print("Max_value:",max(number))

Output

Here is the output of the above program.

Python Program 2

Let us take one more example for finding max value.

# import module for regular expression and collections
import re
#input
string='1bc125cf200c4'
#seperate number from string
number = re.findall('\d+', string)
#convert it into integer
number = map(int, number)
print("Max_value:",max(number))

Output

Here is the output of the above example.

Conclusion

In this tutorial, we have learned to find maximum numeric value from the given string. We can do this using python regex. It has been explained with examples.