Highlighting¶
Rich will automatically highlight patterns in text, such as numbers, strings, collections, booleans, None, and a few more exotic patterns such as file paths, URLs and UUIDs.
You can disable highlighting either by setting highlight=False
on print()
or log()
, or by setting highlight=False
on the Console
constructor which disables it everywhere. If you disable highlighting on the constructor, you can still selectively enable highlighting with highlight=True
on print / log.
Custom Highlighters¶
If the default highlighting doesn’t fit your needs, you can define a custom highlighter. The easiest way to do this is to extend the RegexHighlighter
class which applies a style to any text matching a list of regular expressions.
Here’s an example which highlights text that looks like an email address:
from rich.console import Console
from rich.highlighter import RegexHighlighter
from rich.theme import Theme
class EmailHighlighter(RegexHighlighter):
"""Apply style to anything that looks like an email."""
base_style = "example."
highlights = [r"(?P<email>[\w-]+@([\w-]+\.)+[\w-]+)"]
theme = Theme({"example.email": "bold magenta"})
console = Console(highlighter=EmailHighlighter(), theme=theme)
console.print("Send funds to money@example.org")
The highlights
class variable should contain a list of regular expressions. The group names of any matching expressions are prefixed with the base_style
attribute and used as styles for matching text. In the example above, any email addresses will have the style “example.email” applied, which we’ve defined in a custom Theme.
Setting the highlighter on the Console will apply highlighting to all text you print (if enabled). You can also use a highlighter on a more granular level by using the instance as a callable and printing the result. For example, we could use the email highlighter class like this:
console = Console(theme=theme)
highlight_emails = EmailHighlighter()
console.print(highlight_emails("Send funds to money@example.org"))
While RegexHighlighter
is quite powerful, you can also extend its base class Highlighter
to implement a custom scheme for highlighting. It contains a single method highlight
which is passed the Text
to highlight.
Here’s a silly example that highlights every character with a different color:
from random import randint
from rich import print
from rich.highlighter import Highlighter
class RainbowHighlighter(Highlighter):
def highlight(self, text):
for index in range(len(text)):
text.stylize(f"color({randint(16, 255)})", index, index + 1)
rainbow = RainbowHighlighter()
print(rainbow("I must not fear. Fear is the mind-killer."))
Builtin Highlighters¶
The following builtin highlighters are available.
ISO8601Highlighter
Highlights ISO8601 date time strings.JSONHighlighter
Highlights JSON formatted strings.