Padding

Spaces can be placed to the left or to the right of a Python string. We can left or right-justify a table of text data with padding—we use ljust and rjust.

Ljust and rjust pad strings

They accept one or two arguments. The first argument is the total length of the result string. The second is the padding character.

An example

Here we use ljust and rjust. If you specify a number that is too small, ljust and rjust do nothing. They return the original string.

s = "Paris"

# Justify to left, add periods.
print(s.ljust(10, "."))

# Justify to right.
print(s.rjust(10))
Paris.....
     Paris

Format

We can use a pattern with the format built-in to pad strings. Any character can be used. But this style of code is likely harder to read.

# Right-align a string in 10 chars.
# ... First char in format string is a space.
value = format("line 1", " >10s")
print(value)

# Left-align a number in 10 chars.
# ... Pad with a star character.
print(format(100, "*<10d"))
    line 1
100*******

Some notes, loop

Consider this—a loop could be used to pad strings. This can be needed for more complex requirements. Continue adding characters until the desired length is met.

A review

To pad strings in Python, we can use the format built-in or directly use ljust and rjust. Even a loop could be used to insert or append spaces.