# Add trailing Zeros to a Python string

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As part of data processing activity we sometimes need to append one string with another. In this article we will see how to append dynamic number of zeros to a given string. This can be done by using various string functions as shown in the programs below.

## Using ljust and len

Python string method ljust() returns the string left justified in a string of length width. Padding is done using the specified fillchar (default is a space). The len() returns the length of the string. We add trailing zeros to the string by manipulating the length of the given string and the ljust function.

## Example

#Add trailing Zeros to a Python string
# initializing string
str = 'Jan-'
print("The given input : " + str(str))
# No. of zeros required
n = 3
# using ljust() adding trailing zero
output = str.ljust(n + len(str), '0')
print("adding trailing zeros to the string is : " + str(output))

## Output

Running the above code gives us the following result −

The given input : Jan-
adding trailing zeros to the string is : Jan-000

## Using format Function

The format() method formats the specified value and insert them inside the string's placeholder. The placeholder is defined using curly brackets: {}. In the below example we take a string of length 7 and use format method to add two trailing zeros.

## Example

str= 'Spring:'
print("\nThe given input : " + str(str))
# using format()adding trailing zero n for number of elememts, '0' for Zero, and '<' for trailing
z = '{:<09}'
output = z.format(str)
print("adding trailing zeros to the string is : " + str(output))

## Output

Running the above code gives us the following result −

The given input : Spring:
adding trailing zeros to the string is : Spring:00
Published on 14-Feb-2020 07:13:26