Section 1.1: Basic Text Wrapping

To start, you can easily import the Text Wrapper library:

import textwrap as tr

For demonstration, let’s define a string sourced from the Python Wikipedia page:

my_str = "Python is an interpreted, high-level and general-purpose programming language."

Imagine your application’s user interface or webpage needs to show this text within a specific width. If the text exceeds that width, it should automatically break into multiple lines. Breaking the text at an exact width can lead to poor readability, as some words may split awkwardly.

The Text Wrapper library simplifies this task. Instead of implementing complex logic to identify word boundaries, you can use the following code:

lines = tr.wrap(my_str, width=30)

This effectively divides the sentence into three lines because we’ve set the width at 30 characters, ensuring that the text doesn’t overflow in the UI.

In this video, "Python [textwrap] 01 Wrap() and Fill()", you can see how to use the wrap() function to format your strings properly.

Section 1.2: Creating Print-Ready Text

You might find that using wrap() requires additional looping to print each line separately. To streamline this process, Python provides another function called fill():

tr.fill(my_str, width=30)

This function returns a single wrapped string that is "print-ready," complete with line breaks.

Section 1.3: Truncating Text

Displaying all text in an application interface isn’t always necessary. You’ve likely encountered truncated text with indicators such as "...(more)," suggesting additional content is available. To replicate this in Python, you can use the shorten() function:

tr.shorten(my_str, width=30)

This automatically truncates the string to fit within the specified width. If you adjust the width to 80, for instance, the string remains intact since it's short enough:

tr.shorten(my_str, width=80)

You can also customize the placeholder. If you prefer a different indicator, simply modify it like so:

tr.shorten(my_str, width=30, placeholder=' ...(more)')

Section 1.4: Cleaning Up Strings

The Text Wrapper library not only wraps and truncates text, but it also helps clean up messy formats. This is particularly useful when dealing with text from external sources. Suppose we have a string with inconsistent indentation:

my_str2 = '''

Python is an interpreted,

high-level and general-purpose

programming language.

'''

Using the dedent() function, we can remove excess whitespace easily:

tr.dedent(my_str2)

This function is effective for any amount of leading whitespace.

Section 1.5: Custom Indentation

If you wish to add indentation rather than remove it, the Text Wrapper library can accommodate that as well. The indent() function allows you to prefix each line with a custom string. For example:

some_code = '''

import textwrap as tr

print("hello world!")

for i in range(10):

print(i)

'''

You can add two spaces before each line:

tr.indent(some_code, ' ')

For a more interesting output, try customizing the indent string:

tr.indent(some_code, '>>> ')

To apply the prompt only to certain lines, use a predicate function with the indent method.

Section 1.6: Reusing TextWrapper Instances

Thus far, we've explored five functions from the Text Wrapper library. These functions create a TextWrapper instance each time they are called. However, if you have multiple strings that require wrapping, or you need methods that are specific to the TextWrapper class, you can instantiate the class directly:

wrapper = tr.TextWrapper(width=50, initial_indent="- ")

Now, let's create a list of strings to wrap:

my_strings = [

"Python is an interpreted, high-level and general-purpose programming language.",

"Python's design philosophy emphasizes code readability with its notable use of significant indentation.",

"Its language constructs and object-oriented approach aim to help programmers write clear, logical code for small and large-scale projects.",

"Python is dynamically-typed and garbage-collected.",

"It supports multiple programming paradigms, including structured (particularly, procedural), object-oriented and functional programming.",

"Python is often described as a 'batteries included' language due to its comprehensive standard library."

]

You can then wrap and print each sentence easily:

for s in my_strings:

print(wrapper.fill(s))