Python - Extract digits from Tuple list

Given a list of tuples containing numbers of varying lengths, the task is to extract all unique digits present in those tuples.

Examples:

Input: list = [(15, 3), (3, 9)] 
Output: [9, 5, 3, 1]

Input: list = [(15, 3)] 
Output: [5, 3, 1] 

Using List Comprehension + Set

t = [(15, 3), (3, 9), (1, 10), (99, 2)]

temp = ''.join([str(i) for s1 in t for i in s1])
res = [int(i) for i in set(temp)]
print(res)

[1, 5, 2, 3, 9, 0]

Explanation:

• [str(i) for s1 in t for i in s1]: Converts each number in all tuples to a string.
• ' '.join(...): Joins all string numbers into one continuous string.
• set(temp): Removes duplicate digits.
• [int(i) for i in set(temp)]: Converts unique string digits back to integers.

Using map() + chain.from_iterable() + set()

from itertools import chain

t = [(15, 3), (3, 9), (1, 10), (99, 2)]
s = map(str, chain.from_iterable(t))
res = {d for n in s for d in n}
print(res)

{'0', '2', '9', '5', '3', '1'}

Explanation:

• chain.from_iterable(t): Flattens all tuples into a single sequence.
• map(str, ...): Converts each number to a string.
• {d for n in s for d in n}: Extracts individual digits and keeps only unique ones.

Using Regex

A compact method that converts the tuple list to a string, removes unwanted characters using regex, and extracts unique digits using set().

import re

t = [(15, 3), (3, 9), (1, 10), (99, 2)]
s = re.sub(r'[\[\]\(\), ]', '', str(t))
res = [int(i) for i in set(s)]
print(res)

[1, 5, 0, 2, 9, 3]

Explanation:

• str(t): Converts tuple list to string.
• re.sub(r'[\[\]\(\), ]', '', str(t)): Removes brackets, commas, and spaces.
• set(s): Collects unique digit characters.
• int(i) for i in set(s): Converts them back to integers.

Using Nested Loops + set()

A simple approach that iterates through each tuple, collects all digits as strings, and uses set() to extract unique digits.

t = [(15, 3), (3, 9), (1, 10), (99, 2)]

s = ''
for x in t:
    for y in x:
        s += str(y)
res = list(map(int, set(s)))
print(res)

[5, 1, 2, 3, 0, 9]

Explanation:

• s += str(y): Adds each number as a string.
• set(s): Removes duplicate digits.
• map(int, set(s)): Converts unique string digits into integers.

Related Articles:

• list comprehension
• regex
• itertools
• Python | Convert list of tuples into digits
• Python - Extract numbers from list of strings