CODEWITHSUNDEEP
pythonpython-2.7
Saravana Murthy
Saravana Murthy

Reputation: 553

How to add Trailing zeroes to an integer

I have a positive integer variable which can have values between 0 to 999. This integer is then passed to a software.

To pass into this software the integer should always be 3 digits. But the problem is, it should have trailing zeroes.

For example:

1 should be passed as 100
19 should be passed as 190
255 should be passed as 255

It can be done by checking the length of the variable and multiplying with 10 or 100 depending on the length. But is there any better Python alternative. Also this doesn't work for value 0.

(Note: Trailing Zeroes is because the integer value is actually a millisecond value. The software reads the values digit by digit and it always needs 3 digits)

Upvotes: 8

Views: 29280

Answers (4)

ShadowRanger
ShadowRanger

Reputation: 155323

You don't even need the formatting operators for this, just plain str methods. To right justify with zeroes:

x.zfill(3)

To left justify with zeroes:

x.ljust(3, '0')

You'd need to wrap x in str first in this scenario if x is currently an int. At that point, it may be worth just using the formatting operators as others have suggested to directly produce the final str, with no intermediate str, when justification is required.

Upvotes: 18

Karen Clark
Karen Clark

Reputation: 166

You can do this by using ljust and str, then casting the result as an int.

>>> numbers = [1, 19, 255]
>>> [int(str(num).ljust(3, '0')) for num in numbers]
[100, 190, 255]

More on ljust here: https://docs.python.org/2/library/stdtypes.html#string-methods

Upvotes: 5

Adam Smith
Adam Smith

Reputation: 54163

As mentioned in the question, milliseconds should be 1 -> 001, not 100. One millisecond is a thousandth of a second, not a tenth.

[str(num).zfill(3) for num in numbers]

or using Tigerhawk's method with the opposite alignment:

["{:>03}".format(num) for num in numbers]

Upvotes: 3

TigerhawkT3
TigerhawkT3

Reputation: 49320

I don't know why the zeros got chopped off (ideally you should fix the source of the problem), but you can format the numbers as strings and then turn them back into ints:

numbers = [1, 19, 255]
numbers = [int('{:<03}'.format(number)) for number in numbers]

This left-aligns each number with <, in a field 3 characters wide, filling extra characters with 0.

Upvotes: 7

Related Questions