In this shot, we’ll learn how to use
for loops in Python to generate a left arrow pattern using numbers.
We will use three
for loops: one for the upper, one for the middle, and one for the lower part.
Let’s look at the code below:
# Number of rows n=6 # Upper part for i in range((n - 1) // 2, 0, -1): for j in range(i): print(" ", end = " ") print(i+1) # Middle part for i in range(n): print(i+1, end = " ") print() # Lower part for i in range(1, ((n - 1) // 2) + 1): for j in range(i): print(" ", end = " ") print(i+1)
Line 2: We take the input for the number of rows.
Lines 5 to 8: We create a
for loop to generate the upper portion of the arrow. The outer loop will only run twice because
n-1 // 2 will give us
n = 6). The inner loop will run
j times to print the spaces and, when it breaks, the outer loop will print
Lines 11 to 13: We create another
for loop to generate the middle portion of the arrow. We print
i+1 on each iteration. For example,
i=0 at the first iteration. When we do
i+1, it is
1. That is what is printed at the start. Finally,
print() moves the cursor to the next line.
Lines 16 to 20: We create a
for loop to generate the lower portion of the arrow.
Line 18: We use the
end statement to stay on the same line.
Line 19: We use the
print() statement to move to the next line.
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