** I want to use two for-loops instead of two while-loops **
i = 7
while i >= 1:
j = i
while j <= 7:
print(j, end =" ")
J += 1
i -= 1
print()
The following is the for-loop
equivalent:
for i in range(7, 0, -1):
j = i
for j in range(i, 8):
print(j, end=" ")
print()
The key is the correct use of range(start, stop, step)
. See also this.