Pretty Printing
除了语法高亮，Rich 还会为容器类型（list, dict, set）进行格式化
Run the following command to see an example of pretty printed output:
pprint method
pprint() 方法 提供了一些参数用来调整对象的打印方式
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| >>> from rich.pretty import pprint
>>> pprint(locals())
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Indent guides
Indent guides 设置可以高亮锁紧部分，使我们更容易阅读更深层次的嵌套输出。
pprint 方法默认启用缩进指南。你可以设置 indent_guides=False 来禁用这个功能。
Expand all
Rich 在扩展数据结构方面是相当保守的，它将尽量在每一行中容纳更多的数据。你可以通过设置 expand_all=True 来告诉 Rich 完全展开所有数据结构。
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| >>> pprint(["eggs", "ham"], expand_all=True)
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Truncating pretty output
长数据结构可能难以阅读，需要滚动页面才能找到自己想要的数据；Rich 可以截断容器和长字符串，让你在不影响终端的情况下获得概览
如果您将 max_length 参数设置为一个整数
- 超过长度的容器类型将会被截断；并显示一个省略号 “……” 以及未显示的元素数量。
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| >>> pprint(locals(), max_length=2)
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- 超过长度的 str 类型将会被截断，并显示 “+” 号以及未显示的字符数量
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| >>> pprint("Where there is a Will, there is a Way", max_string=21)
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Pretty renderable
Pretty 类用于来将 pretty printing data 插入到另一个可渲染数据中。
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| from rich import print
from rich.pretty import Pretty
from rich.panel import Panel
pretty = Pretty(locals())
panel = Panel(pretty)
print(panel)
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There are a large number of options to tweak the pretty formatting, See the Pretty reference for details.
Rich Repr Protocol
Rich 能够对任何输出进行语法高亮，但格式化只限于内建容器（built-in containers）、dataclasses 和其他 Rich 知道的对象，例如由 attrs 库生成的对象。要将 Rich 的格式化功能添加到自定义对象中，你可以实现 rich repr protocol
Run the following command to see an example of what the Rich repr protocol can generate:
First, let’s look at a class that might benefit from a Rich repr:
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| class Bird:
def __init__(self, name, eats=None, fly=True, extinct=False):
self.name = name
self.eats = list(eats) if eats else []
self.fly = fly
self.extinct = extinct
def __repr__(self):
return f"Bird({self.name!r}, eats={self.eats!r}, fly={self.fly!r}, extinct={self.extinct!r})"
BIRDS = {
"gull": Bird("gull", eats=["fish", "chips", "ice cream", "sausage rolls"]),
"penguin": Bird("penguin", eats=["fish"], fly=False),
"dodo": Bird("dodo", eats=["fruit"], fly=False, extinct=True)
}
print(BIRDS)
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The result of this script would be:
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| {'gull': Bird('gull', eats=['fish', 'chips', 'ice cream', 'sausage rolls'], fly=True, extinct=False), 'penguin': Bird('penguin', eats=['fish'], fly=False, extinct=False), 'dodo': Bird('dodo', eats=['fruit'], fly=False, extinct=True)}
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输出过长，难以阅读。repr 字符串的信息量很大，但有点冗长，因为它们包括默认参数。如果我们用 Rich 来打印，情况就会有一些改善：
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| {
'gull': Bird('gull', eats=['fish', 'chips', 'ice cream', 'sausage rolls'],
fly=True, extinct=False),
'penguin': Bird('penguin', eats=['fish'], fly=False, extinct=False),
'dodo': Bird('dodo', eats=['fruit'], fly=False, extinct=True)
}
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这样还是会有些冗余和换行
We can solve both these issues by adding the following __rich_repr__ method:
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| def __rich_repr__(self):
yield self.name
yield "eats", self.eats
yield "fly", self.fly, True
yield "extinct", self.extinct, False
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Now if we print the same object with Rich we would see the following:
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| {
'gull': Bird(
'gull',
eats=['fish', 'chips', 'ice cream', 'sausage rolls']
),
'penguin': Bird('penguin', eats=['fish'], fly=False),
'dodo': Bird('dodo', eats=['fruit'], fly=False, extinct=True)
}
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参数的默认值被忽略，输出更好看了。The output remains readable even if we have less room in the terminal, or our objects are part of a deeply nested data structure:
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| {
'gull': Bird(
'gull',
eats=[
'fish',
'chips',
'ice cream',
'sausage rolls'
]
),
'penguin': Bird(
'penguin',
eats=['fish'],
fly=False
),
'dodo': Bird(
'dodo',
eats=['fruit'],
fly=False,
extinct=True
)
}
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You can add a __rich_repr__ method to any class to enable the Rich formatting. 这个方法应该返回一个 tuple 的迭代器，当然你可以返回 tuple 列表，但是使用 yield 构建生成器是更好的选择。
每个 tuple 描述一个属性
yield value will generate a positional argument.yield name, value will generate a keyword argument.yield name, value, default will generate a keyword argument if value is not equal to default.
If you use None as the name, then it will be treated as a positional argument as well, in order to support having tuple positional arguments.
你也可以让 Rich 生成 angular bracket 风格的 repr，这往往用于没有简单方法重新创建对象的构造函数的情况（where there is no easy way to recreate the object’s constructor）。要做到这一点，请在你的 __rich_repr__ 方法之后立即将函数属性 “angular “设置为 True。比如说。
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| __rich_repr__.angular = True
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This will change the output of the Rich repr example to the following:
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| {
'gull': <Bird 'gull' eats=['fish', 'chips', 'ice cream', 'sausage rolls']>,
'penguin': <Bird 'penguin' eats=['fish'] fly=False>,
'dodo': <Bird 'dodo' eats=['fruit'] fly=False extinct=True>
}
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你可以将 __rich_repr__ 方法添加到第三方库中，而不需要将 Rich 作为一个依赖项。如果没有安装 Rich，那么就不会有任何问题。希望将来会有更多的第三方库采用 Rich repr 方法。
Typing
If you want to type the Rich repr method you can import and return rich.repr.Result, which will help catch logical errors:
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| import rich.repr
class Bird:
def __init__(self, name, eats=None, fly=True, extinct=False):
self.name = name
self.eats = list(eats) if eats else []
self.fly = fly
self.extinct = extinct
def __rich_repr__(self) -> rich.repr.Result:
yield self.name
yield "eats", self.eats
yield "fly", self.fly, True
yield "extinct", self.extinct, False
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Automatic Rich Repr
如果参数的名称与你的属性相同，Rich 可以自动生成一个 repr。
要自动建立一个 rich repr，请使用 auto() 类装饰器。
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| import rich.repr
@rich.repr.auto
class Bird:
def __init__(self, name, eats=None, fly=True, extinct=False):
self.name = name
self.eats = list(eats) if eats else []
self.fly = fly
self.extinct = extinct
BIRDS = {
"gull": Bird("gull", eats=["fish", "chips", "ice cream", "sausage rolls"]),
"penguin": Bird("penguin", eats=["fish"], fly=False),
"dodo": Bird("dodo", eats=["fruit"], fly=False, extinct=True)
}
from rich import print
print(BIRDS)
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Note that the decorator will also create a repr, so you will get an auto-generated repr even if you don’t print with Rich.
If you want to auto-generate the angular type of repr, then set angular=True on the decorator:
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| @rich.repr.auto(angular=True)
class Bird:
def __init__(self, name, eats=None, fly=True, extinct=False):
self.name = name
self.eats = list(eats) if eats else []
self.fly = fly
self.extinct = extinct
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