Python pyyaml 的漂亮输出
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pretty output with pyyaml
提问by Mayur Patel
I have a python project where I'd like to use YAML (pyYaml 3.11), particularly because it is "pretty" and easy for users to edit in a text editor if and when necessary. My problem, though, is if I bring the YAML into a python application (as I will need to) and edit the contents (as I will need to) then writing the new document is typically not quite as pretty as what I started with.
我有一个 python 项目，我想在其中使用 YAML (pyYaml 3.11)，特别是因为它“漂亮”并且用户在必要时可以轻松地在文本编辑器中进行编辑。不过，我的问题是，如果我将 YAML 带入 Python 应用程序（因为我需要）并编辑内容（因为我需要），那么编写新文档通常不像我开始时那么漂亮。
The pyyaml documentation is pretty poor - does not even document the parameters to the dump function. I found http://dpinte.wordpress.com/2008/10/31/pyaml-dump-option/. However, I'm still missing the information I need. (I started to look at the source, but it doesn't seem the most inviting. If I don't get the solution here, then that's my only recourse.)
pyyaml 文档很差 - 甚至没有记录转储函数的参数。我找到了http://dpinte.wordpress.com/2008/10/31/pyaml-dump-option/。但是，我仍然缺少我需要的信息。（我开始查看源，但它似乎不是最吸引人的。如果我在这里没有得到解决方案，那么这是我唯一的办法。）
I start with a document that looks like this:
我从一个看起来像这样的文档开始：
- color green :
inputs :
- port thing :
widget-hint : filename
widget-help : Select a filename
- port target_path :
widget-hint : path
value : 'thing'
outputs:
- port value:
widget-hint : string
text : |
I'm lost and I'm found
and I'm hungry like the wolf.
After loading into python (yaml.safe_load( s )), I try a couple ways of dumping it out:
加载到 python (yaml.safe_load( s )) 后，我尝试了几种转储方法：
>>> print yaml.dump( d3, default_flow_style=False, default_style='' )
- color green:
inputs:
- port thing:
widget-help: Select a filename
widget-hint: filename
- port target_path:
value: thing
widget-hint: path
outputs:
- port value:
widget-hint: string
text: 'I''m lost and I''m found
and I''m hungry like the wolf.
'
>>> print yaml.dump( d3, default_flow_style=False, default_style='|' )
- "color green":
"inputs":
- "port thing":
"widget-help": |-
Select a filename
"widget-hint": |-
filename
- "port target_path":
"value": |-
thing
"widget-hint": |-
path
"outputs":
- "port value":
"widget-hint": |-
string
"text": |
I'm lost and I'm found
and I'm hungry like the wolf.
Ideally, I would like "short strings" to not use quotes, as in the first result. But I would like multi-line strings to be written as blocks, as with the second result. I guess fundamentally, I'm trying to minimize an explosion of unnecessary quotes in the file which I perceive would make it much more annoying to edit in a text editor.
理想情况下，我希望“短字符串”不使用引号，就像第一个结果一样。但是我希望将多行字符串写为块，就像第二个结果一样。我想从根本上说，我试图尽量减少文件中不必要的引号爆炸，我认为这会使在文本编辑器中编辑变得更加烦人。
Does anyone have any experience with this?
有人对这个有经验么？
采纳答案by Anthon
If you can use ruamel.yaml(disclaimer: I am the author of this enhanced version of PyYAML) you can do:
如果您可以使用ruamel.yaml（免责声明：我是 PyYAML 增强版的作者），您可以执行以下操作：
import ruamel.yaml
yaml_str = """\
- color green :
inputs :
- port thing :
widget-hint : filename
widget-help : Select a filename
- port target_path :
widget-hint : path
value : 'thing'
outputs:
- port value:
widget-hint : string
text : |
I'm lost and I'm found
and I'm hungry like the wolf.
"""
data = ruamel.yaml.round_trip_load(yaml_str)
res = ""
for line in ruamel.yaml.round_trip_dump(data, indent=5, block_seq_indent=3).splitlines(True):
res += line[3:]
print(res)
you get:
你得到：
- color green:
inputs:
- port thing:
widget-hint: filename
widget-help: Select a filename
- port target_path:
widget-hint: path
value: thing
outputs:
- port value:
widget-hint: string
text: |
I'm lost and I'm found
and I'm hungry like the wolf.
Not exactly what you did start out with (but after this round-trip it is stable). With more recent versions of ruamel.yaml you can set both the indent and the relative indent of a sequence -within that indent. The latter however also influences your top-level sequence, hence the post processing.
不完全是你开始时所做的（但在这次往返之后它是稳定的）。使用 ruamel.yaml 的更新版本，您可以在该缩进中设置序列的缩进和相对-缩进。然而，后者也会影响您的顶级序列，从而影响后期处理。
Important (to me) things that are preserved: comments, anchors, mapping merges, and literal scalars ( multi-line using |)
保留的重要（对我而言）事物：注释、锚点、映射合并和文字标量（多行使用|）
回答by Aryeh Leib Taurog
Try the pyamlpretty printer. It gets closer, though it does put quotes around short strings with spaces in them:
试试pyaml漂亮的打印机。它变得更近了，尽管它确实在短字符串周围加上了引号，其中包含空格：
>>> print pyaml.dump(d3)
- 'color green':
inputs:
- 'port thing':
widget-help: 'Select a filename'
widget-hint: filename
- 'port target_path':
value: thing
widget-hint: path
outputs:
- 'port value':
widget-hint: string
text: |
I'm lost and I'm found
and I'm hungry like the wolf.
