F-string not formatting floats into an integer

Question

Usually, I use % string formatting. But, as I discovered f-string is the new way of string formatting and it is faster as well, I want to use it.
But, I am facing a problem when formatting a float into an integer using f-string. Following is what I have tried:
Using % string formatting

'%5d'%1223      # yields --> ' 1223'
'%5d'%1223.555  # yields --> ' 1223'

Using f-string formatting

f'{1223:5d}'     # yields --> ' 1223' ==> correct
f'{1223.555:5d}' # gives error
# error is "ValueError: Unknown format code 'd' for object of type 'float'"

Am I missing something?

If I try `f'{1223.555:5.0f}'`, it'll round off and yeild " 1224", which not what I want. — Satish Thorat, Jul 13 '23 at 09:21

911 · Answer 1 · 2023-07-13T09:30:32.147

2

The reason for this error is that the format specifier d is specifically for formatting integers, not floats.You can use the general format specifier f instead.

f'{int(1223.555):5d}'

edited Jul 13 '23 at 09:30

answered Jul 13 '23 at 08:55

911

542
2
12

In this way, it's giving `'1223.555000'` which is not what I want. Is there any other standard way to do it? – Satish Thorat Jul 13 '23 at 09:25
I just edited the answer, is this what you want? – 911 Jul 13 '23 at 09:31
Yeah. But, it's hack. Anyways, this is the only, I guess. Thanks though! – Satish Thorat Jul 13 '23 at 09:33
@SatishThorat It's not a hack. The old style formatting (% operator) implicitly converts float to int when the format specifier is d. The output you want is a float converted to int (rounded down) so why is converting the float to int a hack? – DarkKnight Jul 13 '23 at 09:58
Ohh.. That's the difference. Thanks for making it clear. – Satish Thorat Jul 14 '23 at 02:33

F-string not formatting floats into an integer

1 Answers1