How can I parse a YAML file in Python

Question

User · Answer

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.safe_load(stream))
    except yaml.YAMLError as exc:
        print(exc)

Use safe_load() unless you really have full control over the input, need it (seldom the case) and know what you are doing.

If you are using pathlib Path for manipulating files, you are better of using the new API ruamel.yaml provides:

from ruamel.yaml import YAML
from pathlib import Path

path = Path('example.yaml')
yaml = YAML(typ='safe')
data = yaml.load(path)

User · Answer

To access any element of a list in a YAML file like this  global    registry      url  dtr- 5000      repoPath    dbConnectionString  jdbc oracle thin  x x x x 1521 abcd  You can use following python script  import yaml  with open  quot  some path to yaml file quot    r   as f      valuesYaml   yaml load f  Loader yaml FullLoader   print valuesYaml  global    dbConnectionString

User · Answer

First install pyyaml using pip3    Then import yaml module and load the file into a dictionary called  my dict    import yaml with open  filename yaml   as f      my dict   yaml safe load f    That s all you need  Now the entire yaml file is in  my dict  dictionary

User · Answer

Read  amp  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 safe 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  amp  write  JSON  Nice for writing human-readable data  VERY commonly used  read  amp  write  YAML  YAML is a superset of JSON  but easier to read  read  amp  write  comparison of JSON and YAML  pickle  A Python serialization format  read  amp  write  MessagePack  Python package   More compact representation  read  amp  write  HDF5  Python package   Nice for matrices  read  amp  write  XML  exists too  sigh   read  amp  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

User · Answer

I use ruamel yaml  Details  amp  debate here   from ruamel import yaml  with open filename   r   as fp      read data   yaml load fp    Usage of ruamel yaml is compatible  with some simple solvable problems  with old usages of PyYAML and as it is stated in link I provided  use   from ruamel import yaml   instead of   import yaml   and it will fix most of your problems   EDIT  PyYAML is not dead as it turns out  it s just maintained in a different place

User · Answer

usr bin env python  import sys import yaml  def main argv        with open argv 0   as stream          try               print yaml load stream               return 0         except yaml YAMLError as exc              print exc              return 1  if   name         main         sys exit main sys argv 1

User · Answer

Example        defaults yaml   url  https   www google com      environment py   from ruamel import yaml  data   yaml safe load open  defaults yaml    data  url

User · Answer

The easiest and purest method without relying on C headers is PyYaml  documentation   which can be installed via pip install pyyaml     usr bin env python  import yaml  with open  quot example yaml quot    r   as stream      try          print yaml safe load stream       except yaml YAMLError as exc          print exc   And that s it  A plain yaml load   function also exists  but yaml safe load   should always be preferred unless you explicitly need the arbitrary object serialization deserialization provided in order to avoid introducing the possibility for arbitrary code execution  Note the PyYaml project supports versions up through the YAML 1 1 specification  If YAML 1 2 specification support is needed  see ruamel yaml as noted in this answer

[python] How can I parse a YAML file in Python

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