Python String ljust() Method

Python ljust() method is used to left-justify a string, padding it with a specified character (space by default) to reach a desired width. This method is particularly useful when we want to align text in a consistent format, such as in tables or formatted outputs.

Here's a basic example of how to use ljust() method:

s1 = "Hello"
s2 = s1.ljust(10)
print(s2)

Hello     

Explanation:

• In this example, the string "Hello" is left-justified to a width of 10 characters, with spaces added to the right.

Syntax of ljust() method

string.ljust(width, fillchar=' ')

Parameters:

• width: The total width of the resulting string. If the original string is shorter than this width, it will be padded with the fillchar.
• fillchar (optional): The character to use for padding. The default is a space.

Return Type:

• Returns a new string of given length after substituting a given character in right side of original string.

Using the default fill character

The ljust() method can be used without specifying a fillchar, in which case it defaults to a space.

s = "Python"
# Left-aligning the string with a total width of 12
res = s.ljust(12)
print(res)    

Python      

Explanation:

• The string s is left-aligned in a field of width 12.
• The remaining space is filled with spaces.

Specifying a custom fill character

Sometimes, we may want to use a character other than a space to fill the remaining space. The ljust() method allows you to specify a custom fillchar.

s = "Data"

# Left-aligning the string with 
# a width of 10 and using '-' as the fill character
res = s.ljust(10, '-')
print(res)  

Data------

Explanation:

• The fillchar parameter is set to '-', so the remaining space is filled with dashes.
• This can be useful for creating custom formatting styles.

Combining ljust() with other string methods

ljust() method can also be used alongside other string methods to achieve more complex formatting.

s = "Align"

# Left-aligning the string and converting it to uppercase
res = s.ljust(10).upper()
print(res) 

ALIGN     

Explanation:

• The string s is left-aligned in a field of width 10.
• The resulting string is then converted to uppercase using the .upper() method.