CODEWITHSUNDEEP
python-3.xpyyaml
Alex Barysevich
Alex Barysevich

Reputation: 614

yaml.safe_load returns string instead of object

I have this piece of code:

    config_object = yaml.safe_load(config_string)
    print("passed config: {}".format(config_object)) 
    ^^ prints expected yaml structure

    print("deserialized config object type: {}".format(type(config_object)))
    ^^ prints deserialized config object type: <class 'str'>

    value = config_object["field1"]["field2"]["field3"]
    ^^  Error: string indices must be integers

My yaml config:

   ---
   field1:
     field2:
       field3: value
     field4: value
   ...

I do not understand why string is returned. And I do not see any string return type here: https://pyyaml.org/wiki/PyYAMLDocumentation

Upvotes: 6

Views: 9155

Answers (3)

hoijui
hoijui

Reputation: 3914

It turns out, that trying to load invalid YAML data returns a str (with both yaml.load and yaml.safe_load). I would say, that is very bad, but... that's how it is. I accidentally tried to load TOML files with yaml.load, and it also just returns the TOML file content as a string, without any error.

General Solution

Parse your YAML data with something else, be it an other YAML library (possibly in an other language then Python) or in an IDE with YAML parsing support Figure out the problem there, fix it, and then go back to using yaml.load with the now valid YAML data.

Upvotes: 1

Karl
Karl

Reputation: 79

I had the same problem with different data:

train:images/train

I solved the issue by adding a space after the colon:

train: images/train

Upvotes: 7

Bas Krahmer
Bas Krahmer

Reputation: 651

The trick is to wrap your function argument with open() as follows:

config_object = yaml.safe_load(open(config_string))

Upvotes: 5

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