Search code examples
pythonnested-loops

I cant get my code to draw a number pattern with nested loops in Python that will align all number printouts in a neat manner

Use nested for loops to create the following printout:

enter image description here

The number of rows should be read from the user. Use formatted printouts so that the numbers are aligned even for two-digit numbers. • All printed numbers correspond to column numbers. • No number is printed if the column number is less than the row number. • Print a suitable number of spaces to fill an empty column.

# Program to print a pattern with numbers

print("Program to print a pattern with numbers ")
print("-" * 50)
n = int(input("Please enter the number of rows "))
print("-" * 50)

for i in range(n + 1):
    # Increase triangle hidden
    for j in range(i):
        print(" ", end=' ')
    #  Decrease triangle to include numbers in pattern not in increment
    for j in range(i, n):
        print(j + 1, end=" ")
    print()

The code above produces the required output but the numbers are not aligned in an input with 2 digits. How do I format the iterables to make a perfectly aligned output printout.

Output: enter image description here

Solution

  • This is how you might modify your code to use str.rjust. Adjust the 2 in rjust(2) to whatever number you want.

    print("Program to print a pattern with numbers ")
print("-" * 50)
n = int(input("Please enter the number of rows "))
print("-" * 50)

for i in range(n + 1):
    # Increase triangle hidden
    for j in range(i):
        print(" ".rjust(2), end="  ")
    #  Decrease triangle to include numbers in pattern not in increment
    for j in range(i, n):
        print(str(j+1).rjust(2), end="  ")
    print()

    For your example, this gives:

    Program to print a pattern with numbers 
--------------------------------------------------
Please enter the number of rows 12
--------------------------------------------------
 1   2   3   4   5   6   7   8   9  10  11  12  
     2   3   4   5   6   7   8   9  10  11  12  
         3   4   5   6   7   8   9  10  11  12  
             4   5   6   7   8   9  10  11  12  
                 5   6   7   8   9  10  11  12  
                     6   7   8   9  10  11  12  
                         7   8   9  10  11  12  
                             8   9  10  11  12  
                                 9  10  11  12  
                                    10  11  12  
                                        11  12  
                                            12