rich/README.md

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# Rich
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[中文 readme](./README.cn.md)
Rich is a Python library for _rich_ text and beautiful formatting in the terminal.
The [Rich API](https://rich.readthedocs.io/en/latest/) makes it easy to add color and style to terminal output. Rich can also render pretty tables, progress bars, markdown, syntax highlighted source code, tracebacks, and more — out of the box.
![Features](https://github.com/willmcgugan/rich/raw/master/imgs/features.png)
For a video introduction to Rich see [calmcode.io](https://calmcode.io/rich/introduction.html) by [@fishnets88](https://twitter.com/fishnets88).
## Compatibility
Rich works with Linux, OSX, and Windows. True color / emoji works with new Windows Terminal, classic terminal is limited to 8 colors. Rich requires Python 3.6.1 or later.
Rich works with [Jupyter notebooks](https://jupyter.org/) with no additional configuration required.
## 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](https://rich.readthedocs.io/en/latest/introduction.html#quick-start) method, which has the same signature as the builtin Python function. Try this:
```python
from rich import print
print("Hello, [bold magenta]World[/bold magenta]!", ":vampire:", locals())
```
![Hello World](https://github.com/willmcgugan/rich/raw/master/imgs/print.png)
## Using the Console
For more control over rich terminal content, import and construct a [Console](https://rich.readthedocs.io/en/latest/reference/console.html#rich.console.Console) object.
```python
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:
```python
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:
```python
console.print("Hello", "World!", style="bold red")
```
The output will be something like the following:
![Hello World](https://github.com/willmcgugan/rich/raw/master/imgs/hello_world.png)
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](https://en.wikipedia.org/wiki/BBCode). Here's an example:
```python
console.print("Where there is a [bold cyan]Will[/bold cyan] there [u]is[/u] a [i]way[/i].")
```
![Console Markup](https://github.com/willmcgugan/rich/raw/master/imgs/where_there_is_a_will.png)
### 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.
```python
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:
![Log](https://github.com/willmcgugan/rich/raw/master/imgs/log.png)
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.
### Logging Handler
You can also use the builtin [Handler class](https://rich.readthedocs.io/en/latest/logging.html) to format and colorize output from Python's logging module. Here's an example of the output:
![Logging](https://github.com/willmcgugan/rich/raw/master/imgs/logging.png)
## Emoji
To insert an emoji in to console output place the name between two colons. Here's an example:
```python
>>> console.print(":smiley: :vampire: :pile_of_poo: :thumbs_up: :raccoon:")
😃 🧛 💩 👍 🦝
```
Please use this feature wisely.
## Tables
Rich can render flexible [tables](https://rich.readthedocs.io/en/latest/tables.html) with unicode box characters. There is a large variety of formatting options for borders, styles, cell alignment etc.
![table movie](https://github.com/willmcgugan/rich/raw/master/imgs/table_movie.gif)
The animation above was generated with [table_movie.py](https://github.com/willmcgugan/rich/blob/master/examples/table_movie.py) in the examples directory.
Here's a simpler table example:
```python
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", "$275,000,000", "$375,126,118"
)
table.add_row(
"May 25, 2018",
"[red]Solo[/red]: A Star Wars Story",
"$275,000,000",
"$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:
![table](https://github.com/willmcgugan/rich/raw/master/imgs/table.png)
Note that console markup is rendered in the same way 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:
![table2](https://github.com/willmcgugan/rich/raw/master/imgs/table2.png)
## Progress Bars
Rich can render multiple flicker-free [progress](https://rich.readthedocs.io/en/latest/progress.html) bars to track long-running tasks.
For basic usage, wrap any sequence in the `track` function and iterate over the result. Here's an example:
```python
from rich.progress import track
for step in track(range(100)):
do_step(step)
```
It's not much harder to add multiple progress bars. Here's an example taken from the docs:
![progress](https://github.com/willmcgugan/rich/raw/master/imgs/progress.gif)
The columns may be configured to show any details you want. Built-in columns include percentage complete, file size, file speed, and time remaining. Here's another example showing a download in progress:
![progress](https://github.com/willmcgugan/rich/raw/master/imgs/downloader.gif)
To try this out yourself, see [examples/downloader.py](https://github.com/willmcgugan/rich/blob/master/examples/downloader.py) which can download multiple URLs simultaneously while displaying progress.
## Columns
Rich can render content in neat [columns](https://rich.readthedocs.io/en/latest/columns.html) with equal or optimal width. Here's a very basic clone of the (MacOS / Linux) `ls` command which displays a directory listing in columns:
```python
import os
from rich import print
from rich.columns import Columns
directory = os.listdir(sys.argv[1])
print(Columns(directory))
```
The following screenshot is the output from the [columns example](https://github.com/willmcgugan/rich/blob/master/examples/columns.py) which displays data pulled from an API in columns:
![columns](https://github.com/willmcgugan/rich/raw/master/imgs/columns.png)
## Markdown
Rich can render [markdown](https://rich.readthedocs.io/en/latest/markdown.html) 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:
```python
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:
![markdown](https://github.com/willmcgugan/rich/raw/master/imgs/markdown.png)
## Syntax Highlighting
Rich uses the [pygments](https://pygments.org/) library to implement [syntax highlighting](https://rich.readthedocs.io/en/latest/syntax.html). Usage is similar to rendering markdown; construct a `Syntax` object and print it to the console. Here's an example:
```python
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:
![syntax](https://github.com/willmcgugan/rich/raw/master/imgs/syntax.png)
## 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):
![traceback](https://github.com/willmcgugan/rich/raw/master/imgs/traceback.png)
Here's what it looks like on Windows:
![traceback_windows](https://github.com/willmcgugan/rich/raw/master/imgs/traceback_windows.png)
See the [rich traceback](https://rich.readthedocs.io/en/latest/traceback.html) documentation for the details.