script_25.py - Remove Duplicates from List Using Loop

Code

#!/usr/bin/env python3
"""Remove duplicates from list using loop"""

numbers = [1, 2, 2, 3, 4, 4, 5, 1, 6, 3]
unique = []

for num in numbers:
    if num not in unique:
        unique.append(num)

print("Original:", numbers)
print("Unique:", unique)

Explanation

Line 4: numbers = [1, 2, 2, 3, 4, 4, 5, 1, 6, 3] - List with duplicate values - Has repeated: 1, 2, 3, 4

Line 5: unique = [] - Empty list to collect unique values - Initialized before loop

Line 7: for num in numbers: - Iterates through each element in original list - num is loop variable (integer type, same as list elements)

Line 8: if num not in unique: - not in is membership operator (negated) - Returns True if num does NOT exist in unique list - Checks membership before adding - Prevents duplicates

Line 9: unique.append(num) - .append() adds element to end of list - Only executes if num not already in unique - First occurrence of each number gets added - Subsequent occurrences are skipped

Result: Preserves order, removes duplicates - Original has duplicates - Unique list: [1, 2, 3, 4, 5, 6] - Order of first appearance preserved