Star Pattern-1 using Python, Make a Right Angled Triangle, Nested Loop.

We are going to make this pattern and understand nested loop concept with logic.

* 
* * 
* * * 
* * * * 
* * * * *

row=5
for i in range(1,row+1):
    for j in range(i):
        print("*",end=" ")
    print()

Genrally,

1. There are two loops, inner loop and outer loop.
2. Outer loop is for row.
3. Inner loop is for column.

Explanation:

1. row=5, we need 5 rows.
2. for i in range(1,row+1): print 1 to 5, why row+1. As you know range(5) would print 0,1,2,3,4 not 5 same as for (1,row+1) it would be (1,6) and print 1,2,3,4,5.
3. for j in range(i): for every row five column is printed. Example:

11 12 13 14 15
21 22 23 24 25

Dry Run Table:

row=5
i -> (1,1+row)->(1,6)
j -> (i)

i	j->range(i)	Output
1	0	*
2	0,1	**
3	0,1,2	***
4	0,1,2,3	****
5	0,1,2,3,4	*****