Write a program to read a list of n integers (positive as well as negative). Create two new lists, one having

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Q. Write a program to read a list of n integers (positive as well as negative). Create two new lists, one having all positive numbers and the other having all negative numbers from the given list. Print all three lists.

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✓ Free question

Concept understanding — List Operations

A shopping list on paper is more than the items written on it — it is the things you can do with it: read the third entry, cross one out, add another at the bottom, check whether "milk" is already there. A Python list is the program's version of that paper: an ordered collection that can hold many values under one name, written in square brackets. List operations are the standard actions the language gives you for working with the whole collection or any part of it.

marks = [78, 92, 65, 88, 71]

The core operations every student must command:

Indexing — fetch one element by its position: marks[0] is 78. Counting starts at zero, so the last of five items is marks[4]. Negative indexes count from the end: marks[-1] is the last element, no matter how long the list grows.
Slicing — fetch a sub-list: marks[1:4] gives the elements at positions 1, 2 and 3. The start is included, the stop is excluded. Leaving an end open means "to the edge": marks[:3] is the first three, marks[2:] is everything from position 2 onward.
Concatenation — joining two lists with the plus sign produces a new, longer list.
Repetition — a list times an integer produces repeated copies, just as with strings: [0] * 5 builds a list of five zeros, a handy way to prepare storage.
Membership — the in and not in tests answer yes or no: 92 in marks is True. No loop needed.
Traversal — a for loop visits every element in order, which is how totals, searches and printouts are written.
Length — len(marks) reports how many elements the list currently holds.

Unlike a string, a list is mutable — it can be changed in place. Assigning marks[2] = 70 genuinely replaces the third element; nothing similar is allowed on a string.

Watch out

Asking for an index that does not exist — marks[10] on a five-item list — crashes with IndexError. A slice, oddly, forgives the same mistake: marks[10:20] just returns an empty list. Examiners love this contrast.

These operations matter because the list is the workhorse container of the whole course: marks of a class, items in a bill, rows read from a file all arrive as lists, and every later technique — searching, counting frequencies, computing averages — is built by combining exactly these few operations.

Read the list, then one pass with an if/else sends each number to the right list.

numbers = [int(input()) for _ in range(int(input("How many? ")))]
positives = [x for x in numbers if x >= 0]
negatives = [x for x in numbers if x < 0]
print(numbers, positives, negatives, sep="\n")

[5, -3, 0, -12, 8, -1]
[5, 0, 8]
[-3, -12, -1]

✓Final answer

Partition with a single scan (or two list comprehensions) and print all three lists — order is preserved.

Read n integers into one list, then make a single pass: numbers >= 0 go to a positives

list, numbers < 0 go to a negatives list (append() on whichever branch matches).

Finally print all three lists.

The idea

This is a classic partition problem: one input list, two output lists, one if/else deciding

where each element belongs. We never modify the original list — we only copy elements out of it.

Program

# Split a list of integers into positives and negatives
n = int(input("How many integers? "))
numbers = []
for i in range(n):
    numbers.append(int(input("Enter integer " + str(i + 1) + ": ")))

positives = []
negatives = []
for num in numbers:
    if num >= 0:
        positives.append(num)
    else:
        negatives.append(num)

print("Original list :", numbers)
print("Positive list :", positives)
print("Negative list :", negatives)

Sample run

How many integers? 6
Enter integer 1: 5
Enter integer 2: -3
Enter integer 3: 0
Enter integer 4: -12
Enter integer 5: 8
Enter integer 6: -1
Original list : [5, -3, 0, -12, 8, -1]
Positive list : [5, 0, 8]
Negative list : [-3, -12, -1]

Key lines explained:

The first loop builds the input list with append() — the standard read-n-values pattern.
if num >= 0 sends zero and positive numbers to positives; only strictly negative values go to negatives. (If your teacher treats 0 as neither, change the test to num > 0 and add an elif num < 0 branch — state your convention in the answer.)
Both output lists preserve the original order because we scan left to right.

✓Final answer

One pass with if num >= 0: positives.append(num) else: negatives.append(num); for input [5, -3, 0, -12, 8, -1] it prints positives [5, 0, 8] and negatives [-3, -12, -1] .

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Q.Write a program to read a list of n integers (positive as well as negative). Create two new lists, one having all positive numbers and the other having all negative numbers from the given list. Print all three lists.

The idea

Program

Sample run

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