Can someone help me figure out this nested while loop
This is what I was given to do:
And this is what I have so far:
hmmm okay i think i see the problem(s)?
so first trace the program ofc...
n is set as one
row is set as an integer from user input (so ima say “5”)
5 > 0 so:
1 <= 5:
print… uhhhh i dont think it’d print anything? so there’s the first problem.
first problem
there’s a comma there in line 6, that might be a problem- (and is end=“” supposed to be there? i doubt that’s necessary..)
okay, so i tested the code, the end="" is defo not supposed to be there…)
you don’t really need a var there (nor do u need a string?), so just put print(n) instead…
continue tracing (cuz the program still doesn't work)
n is set as one
row is set as an integer from user input (so ima say “5”)
5 > 0 so:
1 <= 5:
prints out 1
increment n by 1
…and there’s some unnecessary clutter here (don’t want that, that’d make tracing more difficult :>)
clutter
so we can just… delete some stuff before continuing :3
delete lines 8-9… annnnd when i test the code, it outputs this:
How many rows? 5
1
2
3
4
5
hm, ok, at least it isn’t stuck now? it prints out 5 rows, which is progress.. still gotta continue tracing
continue (again) tracing
5 is > 0 so:
1 <= 5:
prints out 1
increment n by 1
2 <= 5:
prints out…
hmm okay i see now what the next thing u gotta do… gotta do some concatenation..
so, you gotta make it so n = 1 and have it print out str(n) + str(n+1)...
code so far:
n=0
row = int(input("How many rows? "))
if row > 0:
while n <= row:
if n == 0:
print(n+1)
else:
print(str(n) + str(n+1))
n += 1
else:
print("# of rows can't be negative")
…this outputs this:
How many rows? 5
1
12
23
34
45
56
sooo that’s even more progress :DD (sorry if this explanation is long, i’m still a beginner myself…)
okay, so i did the math,
when n=1:
(n) + (n+1) + (2n+1) + (3n+1) + (4n+1) is the formula for printing the 5th row…
(ack ew math get it outta here–)
so how do u do this formula in code? boom:
n=0
row = int(input("How many rows? "))
if row > 0:
while n+1 <= row:
n += 1
spitOut = ""
smth = 0
for nyeheheh in range(n):
smth += 1
spitOut += str(1 + nyeheheh)
print(spitOut)
else:
print("# of rows can't be negative")
now it should work yay
now make it print a newline \n and tweak the formula code to invert back to output this:
12345
1234
123
12
1
and you’ll get the intended output :DD
(explanation is a bit rushed at the end cuz i gtg switch classes)
and that’s it :3 (first post completed yay)
Good morning, even if it is evening.
Here I’ve made a simple demo program,
that You could adapt further for Your needs.
So, You could have same functionality using any kind of loop: for, while, etc.
Happy 
coding!
try:
while True:
try:
n = int(input("Enter the number of rows: "))
except ValueError:
print("Please enter a positive integer\n")
continue
if n < 0:
print("Only positive integers please!\n")
continue
for i in range(1, n + 1):
for j in range(1, i + 1):
print(j, end=" ")
print()
print()
for i in range(n, 0, -1):
for j in range(1, i + 1):
print(j, end=" ")
print()
except KeyboardInterrupt:
print("\nBye!")
/home/me/Pycharm/WelcomeScreen/.venv/bin/python Bb.py
Enter the number of rows: 3.14
Please enter a positive integer
Enter the number of rows: -10
Only positive integers please!
Enter the number of rows: 1
1
1
Enter the number of rows: 9
1
1 2
1 2 3
1 2 3 4
1 2 3 4 5
1 2 3 4 5 6
1 2 3 4 5 6 7
1 2 3 4 5 6 7 8
1 2 3 4 5 6 7 8 9
1 2 3 4 5 6 7 8 9
1 2 3 4 5 6 7 8
1 2 3 4 5 6 7
1 2 3 4 5 6
1 2 3 4 5
1 2 3 4
1 2 3
1 2
1
Enter the number of rows:
Bye!
Process finished with exit code 0