CODEWITHSUNDEEP
pythonstringformattingint
TimeWillTell
TimeWillTell

Reputation: 189

I cannot seem to find the correct formatting spec for preceding zeroes in python

When adding decimal places, it's as simple as 

john = 2
johnmod = format(john, '.2f')
print(johnmod)

and I get 2.00 back, as expected. But, what's the format spec for adding preceding zeros? I would like for the output to be 0002, and the only spec I've found with Google for that is using %04d, which did not work. If it matters, I am running Python 3.3 on windows.

Upvotes: 3

Views: 557

Answers (4)

Aaron Hall
Aaron Hall

Reputation: 394825

Several Pythonic ways to do this,:

First using the string formatting minilanguage, using your attempted method, first zero means the fill, the 4 means to which width:

>>> format(2, "04")
'0002'

Also, the format minilanguage:

>>> '{0:04}'.format(2)
'0002'

the specification comes after the :, and the 0 means fill with zeros and the 4 means a width of four.

New in Python 3.6 are formatted string literals:

>>> two = 2 
>>> f'{two:04}'
'0002'

Finally, the str.zfill method is custom made for this:

>>> str(2).zfill(4)
'0002'

Upvotes: 6

Mark Ransom
Mark Ransom

Reputation: 308111

format(john, '05.2f')

You can add the leading 0 to a floating point f format as well, but you must add the trailing digits (2) and the decimal point to the total.

Upvotes: 1

jonrsharpe
jonrsharpe

Reputation: 121974

You were nearly there:

johnmod = format(john, "04d")

Upvotes: 1

Dair
Dair

Reputation: 16240

Use zfill:

john = 2
johnmod = str(john).zfill(4)
print(johnmod) # Prints: 0002

Upvotes: 2

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