āØSummary: To split a string by a number, use the regex split
method using the “\d
” pattern.
Minimal Example
my_string = "#@1abc3$!*5xyz" # Method 1 import re res = re.split('\d+', my_string) print(res) # Method 2 import re res = re.findall('\D+', my_string) print(res) # Method 3 from itertools import groupby li = [''.join(g) for _, g in groupby(my_string, str.isdigit)] res = [x for x in li if x.isdigit() == False] print(res) # Method 4 res = [] for i in my_string: if i.isdigit() == True: my_string = my_string.replace(i, ",") print(my_string.split(",")) # Outputs: # ['#@', 'abc', '$!*', 'xyz']
Problem Formulation
šProblem: Given a string containing different characters. How will you split the string whenever a number appears?
Method 1: re.split()
TheĀ re.split(pattern, string)
Ā method matches all occurrences of theĀ pattern
Ā in theĀ string
Ā and divides the string along the matches resulting in a list of stringsĀ betweenĀ the matches. For example,Ā re.split('a', 'bbabbbab')
Ā results in the list of stringsĀ ['bb', 'bbb', 'b']
.
Code:
import re my_string = "#@1abc3$!*5xyz" res = re.split('\d+', my_string) print(res) # ['#@', 'abc', '$!*', 'xyz']
Explanation: TheĀ \d
Ā special characterĀ matches any digit between 0 and 9. By using the maximal number of digits as a delimiter, you split along the digit-word boundary.Ā
Method 2: re.findall()
TheĀ re.findall(pattern, string)
Ā method scansĀ string
Ā fromĀ left to right, searching for allĀ non-overlapping matchesĀ of theĀ pattern
. It returns aĀ list of stringsĀ in the matching order when scanning the string from left to right.
Code:
import re my_string = "#@1abc3$!*5xyz" res = re.findall('\D+', my_string) print(res) # ['#@', 'abc', '$!*', 'xyz']
Explanation: TheĀ \
DĀ special characterĀ matches all characters except any digit between 0 and 9. Thus, you are essentially finding all character groups that appear before the occurrence of a digit.
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Method 3: itertools.groupby()
Code:
from itertools import groupby my_string = "#@1abc3$!*5xyz" li = [''.join(g) for _, g in groupby(my_string, str.isdigit)] res = [x for x in li if x.isdigit() == False] print(res) # ['#@', 'abc', '$!*', 'xyz']
Explanation:
- TheĀ
itertools.groupby(iterable, key=None)
Ā function creates an iterator that returns tuplesĀ(key, group-iterator)
Ā grouped by each value ofĀkey
. We use theĀstr.isdigit()
Ā function as key function. - TheĀ
str.isdigit()
Ā function returnsĀTrue
Ā if the string consists only of numeric characters. Thus, you will have a list created by using numbers as separators. Note that this list will also contain the numbers as items within it. - In order to eliminate the numbers, use another list comprehension that checks if an element in the list returned previously is a digit or not with the help of the
isdigit
method. If it is a digit, the item will be discarded. Otherwise it will be stored in the list.
Method 4: Replace Using a for Loop
Approach: Use a for loop to iterate through the characters of the given string. Check if a character is a digit or not. As soon as a digit is found, replace that character/digit with a delimiter string ( we have used a comma here) with the help of the replace() method. This basically means that you are placing a particular character in the string whenever a number appears. Once all the digits are replaced by the separator string, split the string by passing the separator string as a delimiter to the split method.
Code:
my_string = "#@1abc3$!*5xyz" res = [] for i in my_string: if i.isdigit(): my_string = my_string.replace(i, ",") print(my_string.split(",")) # ['#@', 'abc', '$!*', 'xyz']
Conclusion
Phew! We have successfully solved the given problem and managed to do so using four different ways. I hope you found this article helpful and it answered your queries. Please subscribe and stay tuned for more solutions and tutorials.
Happy coding! š
šRelated Read: How to Split a String Between Numbers and Letters?