Loading special characters with PyYaml

Update

the latest version of pyyaml has fixed this bug, upgrade to pyyaml>=5

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Original answer

This seems to be a bug in pyyaml, a workaround is to use their escape sequences:

$ cat test.yaml
- "\U0001f642"
- "\U0001f601"
- "\U0001f62c"

$ python
...
>>> yaml.load(open('test.yaml'))
['🙂', '😁', '😬']

You should upgrade to ruamel.yaml (disclaimer: I am the author of that package), which has this, and many other long standing PyYAML issues, fixed:

import sys
from ruamel.yaml import YAML

yaml = YAML()

with open('emojis.yml') as fp:
    idx = 0
    for c in fp.read():
        print('{:08x}'.format(ord(c)), end=' ')
        idx += 1
        if idx % 4 == 0:
            print()

with open('emojis.yml') as fp:
    data = yaml.load(fp)
yaml.dump(data, sys.stdout)

gives:

0000002d 00000020 0001f642 0000000a 
0000002d 00000020 0001f601 0000000a 
0000002d 00000020 0001f62c 0000000a 
['🙂', '😁', '😬']

---

If you really have to stick with PyYAML, you can do:

import yaml.reader
import re

yaml.reader.Reader.NON_PRINTABLE = re.compile(
    u'[^\x09\x0A\x0D\x20-\x7E\x85\xA0-\uD7FF\uE000-\uFFFD\U00010000-\U0010FFFF]')

to get rid of the error.

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_{Starting with version 0.15.16, ruamel.yaml now also dumps all supplementary plane Unicode without reverting to \Uxxxxxxxx (controllable in the new API via .unicode_supplementary, and depending on allow_unicode).}