Python adding more to a variable then written in the code

Question

I'm trying to make a simple program in python that shows me the numbers 1.0, 1.1 up to 2. This is the code

test = 1.0

while True:
  print(test)
  test += 0.1
  if test > 2.1:
    break

Output:

1.0
1.1
1.2000000000000002
1.3000000000000003
1.4000000000000004
1.5000000000000004
1.6000000000000005
1.7000000000000006
1.8000000000000007
1.9000000000000008
2.000000000000001

Expected output:

1.0
1.1
1.2
1.3
1.4
1.5
1.6
1.7
1.8
1.9
2.0

See the [Python Tutorial](https://docs.python.org/3/tutorial/floatingpoint.html#floating-point-arithmetic-issues-and-limitations) — snakecharmerb, Jan 24 '21 at 15:24

mhhabib · Accepted Answer · 2021-01-24T16:30:19.747

1

Use just float precision

print(f'{test:.1f}')

You don't need to use it while True or break. Use instead

test = 1.0
while test <= 2.1:
    print(f'{test:.1f}')
    test += 0.1

UPDATE: Set your own precitation how much you want. Nomarlly you can set upto 15 point precitation order. Example you want to divide test = 22/7:

print(f'{test:.2f}') -> 3.14
print(f'{test:.2f}') -> 3.142
print(f'{test:.2f}') -> 3.1428
...............................
print(f'{test:.15f}') -> 3.142857142857143

edited Jan 24 '21 at 16:30

answered Jan 24 '21 at 15:19

mhhabib

2,975
1
15
29

How would it be if I wanted to do it like 1.00 instead of 1.0 – Solpip Jan 24 '21 at 16:12
@Solpip update it to `print(f'{test:.2f}')` – mhhabib Jan 24 '21 at 16:24

Sahadat Hossain · Answer 2 · 2021-01-24T15:28:24.183

1

Printing a float with one decimal place outputs the float with one digit after the decimal point. For example, printing 3.14159 with 3.1. Use str.format(), with "{:.1f}" as str

test = 1.0

while True:
  print("{:.1f}".format(test))
  test += 0.1
  if test > 2.1:
    break

Output :

1.0
1.1
1.2
1.3
1.4
1.5
1.6
1.7
1.8
1.9
2.0

edited Jan 24 '21 at 15:28

answered Jan 24 '21 at 15:21

Sahadat Hossain

3,583
2
12
19

Python adding more to a variable then written in the code

2 Answers2