Super practical! In-depth comparison of differences between Python objects

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The complete sample code and files of this article have been uploaded to my Githubrepository https://github.com/CNFeffery/PythonPracticalSkills

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This is the 10th issue of my series of articles "Python Practical Secrets"Python . This series is based on the experience and experience accumulated by the author in my daily work. Each issue brings you a simple trick that can be learned in a few minutes.

As the 10th installment in the series, we're about to learn: deep comparison Pythonof differences between objects.

In many cases, we need to compare the difference between two data. If it is only for numerical objects, then the difference between the two is the so-called difference, but what if we want to compare JSONthe difference between the two data?

Due to JSONthe characteristics of data that can be nested and layered, if you want to clearly find JSONthe difference between the two data and describe it, it is still a bit troublesome to write the method yourself. In this case, we can use deepdiffa DeepDiff()method in a third-party library, which is based on recursive deep comparison of different objects.

pip install deepdiffAfter the installation is complete, you can directly compare the differences between the two objects by importing from deepdiff import DeepDiffthe required functions. JSONThe following is a simple example:

from deepdiff import DeepDiff

obj1 = {
    'level1': [
        {
            'level1-1': 1,
            'level1-2': 1,
            'level1-3': [
                {
                    'level1-3-1': [1, 2, 3]
                }
            ]
        }
    ],
    'level2': 'a'
}

obj2 = {
    'level1': [
        {
            'level1-1': 1,
            'level1-2': 1,
            'level1-3': [
                {
                    'level1-3-1': [1, 2, 1]
                }
            ]
        }
    ],
    'level2': 'b'
}

DeepDiff(obj1, obj2)

It can be seen that the difference content and specific location are specifically declared in the printed test results, which can help us carry out other subsequent processing.

In addition to this, deepdiffthere are very rich additional functions, such as ignoring comparison checks for data of a specified type:

Or by defining a hierarchy rule that DeepDiff()skips the difference check for elements at specified positions:

It also supports the use of regular expressions to define fuzzy hierarchical rules to be ignored. For example, in the following example, we use regular batches to ignore multiple key-value pairs:

Limit the checking precision for floating-point numbers, such as in the following example, significant_digits=2the difference after the second decimal point is ignored:

For more usage, interested readers and friends can move to https://zepworks.com/deepdiff/5.8.2/diff.htmllearn more.

This sharing is over, see you next time~👋