How can I parse a YAML file in Python

我如何解析Python中的YAML文件？

---

The easiest and pureist method without relying on C headers is PyYaml:

#!/usr/bin/env python

import yaml

with open("example.yaml", 'r') as stream:
    try:
        print(yaml.load(stream))
    except yaml.YAMLError as exc:
        print(exc)

And that's it. More info here:

http://pyyaml.org/wiki/PyYAMLDocumentation

---

If you have YAML that conforms to the YAML 1.2 specification (released 2009) then you should use ruamel.yaml (disclaimer: I am the author of that package). It is essentially a superset of PyYAML, which supports most of YAML 1.1 (from 2005).

If you want to be able to preserve your comments when round-tripping, you certainly should use ruamel.yaml.

Upgrading @Jon's example is easy:

import ruamel.yaml as yaml

with open("example.yaml") as stream:
    try:
        print(yaml.load(stream))
    except yaml.YAMLError as exc:
        print(exc)

---

Read & Write YAML files with Python 2+3 (and unicode)

# -*- coding: utf-8 -*-
import yaml
import io

# Define data
data = {'a list': [1, 42, 3.141, 1337, 'help', u'€'],
        'a string': 'bla',
        'another dict': {'foo': 'bar',
                         'key': 'value',
                         'the answer': 42}}

# Write YAML file
with io.open('data.yaml', 'w', encoding='utf8') as outfile:
    yaml.dump(data, outfile, default_flow_style=False, allow_unicode=True)

# Read YAML file
with open("data.yaml", 'r') as stream:
    data_loaded = yaml.load(stream)

print(data == data_loaded)

Created YAML file

a list:
- 1
- 42
- 3.141
- 1337
- help
- €
a string: bla
another dict:
  foo: bar
  key: value
  the answer: 42

Common file endings

.yml and .yaml

Alternatives

CSV: Super simple format (read & write)

JSON: Nice for writing human-readable data; VERY commonly used (read & write)

YAML: YAML is a superset of JSON, but easier to read (read & write, comparison of JSON and YAML)

pickle: A Python serialization format (read & write)

MessagePack (Python package): More compact representation (read & write)

HDF5 (Python package): Nice for matrices (read & write)

XML: exists too *sigh* (read & write)

For your application, the following might be important:

Support by other programming languages

Reading / writing performance

Compactness (file size)

See also: Comparison of data serialization formats

In case you are rather looking for a way to make configuration files, you might want to read my short article Configuration files in Python

链接地址: http://www.djcxy.com/p/20134.html

上一篇: 如何在XML中注释掉一个标记块？

下一篇: 我该如何解析Python中的YAML文件