7.4 KiB
Rich
Rich is a Python library for rendering rich text and beautiful formatting to the terminal.
The Rich API makes it easy to add colorful text (up to 16.7 million colors) with styles (bold, italic, underline etc.) to your script or application. Rich can also render pretty tables, markdown, syntax highlighted source code, and tracebacks -- out of the box.
Installing
Install with pip or your favorite PyPi package manager.
pip install rich
Rich print function
To effortlessly add rich output to your application, you can import the rich print method, which has the same signature as the builtin Python function. Try this:
from rich import print
print("Hello, [bold magenta]World[/bold magenta]!", ":vampire:", locals())
Console Printing
For more control over rich terminal content, import and construct a Console object.
from rich.console import Console
console = Console()
The Console object has a print method which has an intentionally similar interface to the builtin print function. Here's an example of use:
console.print("Hello", "World!")
As you might expect, this will print "Hello World!" to the terminal. Note that unlike the builtin print function, Rich will word-wrap your text to fit within the terminal width.
There are a few ways of adding color and style to your output. You can set a style for the entire output by adding a style keyword argument. Here's an example:
console.print("Hello", "World!", style="bold red")
The output will be something like the following:
That's fine for styling a line of text at a time. For more finely grained styling, Rich renders a special markup which is similar in syntax to bbcode. Here's an example:
console.print("Where there is a [bold cyan]Will[/bold cyan] there [u]is[/u] a [i]way[/i].")
Console Logging
The Console object has a log() method which has a similar interface to print(), but also renders a column for the current time and the file and line which made the call. By default Rich will do syntax highlighting for Python structures and for repr strings. If you log a collection (i.e. a dict or a list) Rich will pretty print it so that it fits in the available space. Here's an example of some of these features.
from rich.console import Console
console = Console()
test_data = [
{"jsonrpc": "2.0", "method": "sum", "params": [None, 1, 2, 4, False, True], "id": "1",},
{"jsonrpc": "2.0", "method": "notify_hello", "params": [7]},
{"jsonrpc": "2.0", "method": "subtract", "params": [42, 23], "id": "2"},
]
def test_log():
enabled = False
context = {
"foo": "bar",
}
movies = ["Deadpool", "Rise of the Skywalker"]
console.log("Hello from", console, "!")
console.log(test_data, log_locals=True)
test_log()
The above produces the following output:
Note the log_locals argument, which outputs a table containing the local variables where the log method was called.
The log method could be used for logging to the terminal for long running applications such as servers, but is also a very nice debugging aid.
Emoji
To insert an emoji in to console output place the name between two colons. Here's an example:
>>> console.print(":smiley: :vampire: :pile_of_poo: :thumbs_up: :raccoon:")
😃 🧛 💩 👍 🦝
Please use this feature wisely.
Markdown
Rich can render markdown and does a reasonable job of translating the formatting to the terminal.
To render markdown import the Markdown class and construct it with a string containing markdown code. Then print it to the console. Here's an example:
from rich.console import Console
from rich.markdown import Markdown
console = Console()
with open("README.md") as readme:
markdown = Markdown(readme.read())
console.print(markdown)
This will produce output something like the following:
Syntax Highlighting
Rich uses the pygments library to implement syntax highlighting. Usage is similar to rendering markdown; construct a Syntax object and print it to the console. Here's an example:
from rich.console import Console
from rich.syntax import Syntax
my_code = '''
def iter_first_last(values: Iterable[T]) -> Iterable[Tuple[bool, bool, T]]:
"""Iterate and generate a tuple with a flag for first and last value."""
iter_values = iter(values)
try:
previous_value = next(iter_values)
except StopIteration:
return
first = True
for value in iter_values:
yield first, False, previous_value
first = False
previous_value = value
yield first, True, previous_value
'''
syntax = Syntax(my_code, "python", theme="monokai", line_numbers=True)
console = Console()
console.print(syntax)
This will produce the following output:
Tables
Rich can render flexible tables with unicode box characters. There is a large variety of formatting options for borders, styles, cell alignment etc. Here's a simple example:
from rich.console import Console
from rich.table import Column, Table
console = Console()
table = Table(show_header=True, header_style="bold magenta")
table.add_column("Date", style="dim", width=12)
table.add_column("Title")
table.add_column("Production Budget", justify="right")
table.add_column("Box Office", justify="right")
table.add_row(
"Dev 20, 2019", "Star Wars: The Rise of Skywalker", "$275,000,0000", "$375,126,118"
)
table.add_row(
"May 25, 2018",
"[red]Solo[/red]: A Star Wars Story",
"$275,000,0000",
"$393,151,347",
)
table.add_row(
"Dec 15, 2017",
"Star Wars Ep. VIII: The Last Jedi",
"$262,000,000",
"[bold]$1,332,539,889[/bold]",
)
console.print(table)
This produces the following output:
Note that console markup is rendered in the same was as print() and log(). In fact, anything that is renderable by Rich may be included in the headers / rows (even other tables).
The Table class is smart enough to resize columns to fit the available width of the terminal, wrapping text as required. Here's the same example, with the terminal made smaller than the table above:
Tracebacks
Rich can render beautiful tracebacks which are easier to read and show more code than standard Python tracebacks. You can set Rich as the default traceback handler so all uncaught exceptions will be rendered by Rich.
Here's what it looks like on OSX (similar on Linux):
Here's what it looks like on Windows:
See the rich traceback documentation for the details.