PYTHON PROGRAM • PATTERNS & NUMBER PROBLEMS

Print a Number Triangle in Python

Learn print a number triangle in python with a short, executable Python example.

BeginnerNested iterationjoin()

PROBLEM UNDERSTANDING

Input and expected output

Sample input
No input required
Sample output
1
1 2
1 2 3
1 2 3 4

COMPLETE PYTHON PROGRAM

Complete Python implementation

python-number-triangle.py
Open in compiler
for row in range(1, 5):
    print(' '.join(str(number) for number in range(1, row + 1)))

GUIDED CODE TOUR • NOT LIVE EXECUTION

Study the program line by line

Use the real compiler button above to run and debug with different inputs.

CURRENT STEP

Select Start to walk through the important lines.

SELECTED LINE

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EXPECTED OUTPUT FOR THE SAMPLE

1
1 2
1 2 3
1 2 3 4
0%Step 0 of 0

PROGRAM EXPLANATION

Algorithm and explanation

  1. Initialize the sample values used to print a number triangle.
  2. Process the data step by step using Nested iteration and join().
  3. Display the result for print a number triangle and compare it with the documented sample output.

This example of print a number triangle processes the sample values in a controlled iteration. It demonstrates Nested iteration and join() and prints a deterministic result that can be checked against the sample output.

EFFICIENCY

Time and space complexity

Time complexity

O(n²)

Auxiliary space

O(1)

DEBUGGING CHECKLIST

Common mistakes

Check this

For print a number triangle, keep the data shape and value types consistent with Nested iteration.

Check this

Keep every dependent statement inside the correct indented Python block.

Check this

Verify the final Nested iteration and join() result against the sample before trying new data.

Try it yourself

Practice: Run the program with the sample input, predict its output, and then test one boundary case of your own.