Json - CSV data format to nested dictionary

snowflake_user
June 19, 2024
226 views
2 votes
3 Answers

I have below csv format. I want it to convert some nested dict.

name,columns,tests
ABC_ESTIMATE_REFINED,cntquota,dbt_expectations.expect_column_to_exist
ABC_ESTIMATE_REFINED,cntquota,not_null
ABC_ESTIMATE_REFINED,is_purged,dbt_expectations.expect_column_to_exist
ABC_ESTIMATE_REFINED,is_purged,not_null

Expected Output

{
    "name": "ABC_ESTIMATE_REFINED",
    "columns": [
        {
            "name": "cntquota",
            "tests": [
                "dbt_expectations.expect_column_to_exist",
                "not_null"
            ]
        },
        {
            "name": "is_purged",
            "tests": [
                "dbt_expectations.expect_column_to_exist",
                "not_null"
            ]
        }
    ]
}

my attempt is below , but not reaching even close to it.

df=pd.read_csv('data.csv')
print(df)
nested_dict = df.groupby(['name','columns']).apply(lambda x: x[['tests']].to_dict(orient='records')).to_dict()
 
print(nested_dict)

Answers

IIUC, you can use nested groupby calls:

out = [{'name': k1, 'columns': [{'name': k2, 'tests': g2['tests'].tolist()}
                                for k2, g2 in g1.groupby('columns')]}
       for k1, g1 in df.groupby('name')]

Since the processing occurs by pairs or columns, you could also imagine a recursive approach:

def group(df, keys):
    if len(keys) > 1:
        key1, key2 = keys[:2]
        return [{key1: k, key2: group(g, keys[1:])}
                for k, g in df.groupby(key1)]
    else:
        return df[keys[0]].tolist()

out = group(df, ['name', 'columns', 'tests'])

Output:

[{'name': 'ABC_ESTIMATE_REFINED',
  'columns': [{'name': 'cntquota',
               'tests': ['dbt_expectations.expect_column_to_exist', 'not_null']},
              {'name': 'is_purged',
               'tests': ['dbt_expectations.expect_column_to_exist', 'not_null']}],
 }]

Demo of the recursive approach with a different order of the keys:

group(df, ['name', 'tests', 'columns'])

[{'name': 'ABC_ESTIMATE_REFINED',
  'tests': [{'tests': 'dbt_expectations.expect_column_to_exist',
             'columns': ['cntquota', 'is_purged']},
            {'tests': 'not_null', 'columns': ['cntquota', 'is_purged']}],
}]

Something like:

g = df.groupby(["name", "columns"]).agg({"tests": list})
      .reset_index().rename(columns={"name": "index", "columns": "name"})
      .set_index("index")

result = {
    "name": g.index[0],
    "columns": g.to_dict(orient="records")
}

Seems to do the job for the expected output in your OP.

Indeed if there is multiple modalities of name you will have to store it as a list of dictionary instead:

df = pd.read_csv(io.StringIO("""name,columns,tests
ABC_ESTIMATE_REFINED,cntquota,dbt_expectations.expect_column_to_exist
ABC_ESTIMATE_REFINED,cntquota,not_null
ABC_ESTIMATE_REFINED,is_purged,dbt_expectations.expect_column_to_exist
ABC_ESTIMATE_REFINED,is_purged,not_null
ABC_ESTIMATE_REFINED2,cntquota,dbt_expectations.expect_column_to_exist
ABC_ESTIMATE_REFINED2,cntquota,not_null
ABC_ESTIMATE_REFINED2,is_purged,dbt_expectations.expect_column_to_exist
ABC_ESTIMATE_REFINED2,is_purged,not_null"""))

g = df.groupby(["name", "columns"]).agg({"tests": list})
      .reset_index().rename(columns={"name": "index", "columns": "name"})
      .set_index("index")

result = []
for key in g.index.unique():
    result.append({
        "name": key,
        "columns": g.loc[key,:].to_dict(orient="records")
    })

Which will render:

[{'name': 'ABC_ESTIMATE_REFINED',
  'columns': [{'name': 'cntquota',
    'tests': ['dbt_expectations.expect_column_to_exist', 'not_null']},
   {'name': 'is_purged',
    'tests': ['dbt_expectations.expect_column_to_exist', 'not_null']}]},
 {'name': 'ABC_ESTIMATE_REFINED2',
  'columns': [{'name': 'cntquota',
    'tests': ['dbt_expectations.expect_column_to_exist', 'not_null']},
   {'name': 'is_purged',
    'tests': ['dbt_expectations.expect_column_to_exist', 'not_null']}]}]

import pandas as pd

# Read the CSV file into a DataFrame
df = pd.read_csv('data.csv')

# Initialize an empty dictionary to hold the final nested structure
nested_dict = {}

# Group by 'name' and 'columns'
grouped = df.groupby(['name', 'columns'])['tests'].apply(list).reset_index()

# Iterate through the grouped DataFrame to construct the nested dictionary
for _, row in grouped.iterrows():
    name = row['name']
    column = row['columns']
    tests = row['tests']

    # If the name is not in the dictionary, add it with an empty 'columns' list
    if name not in nested_dict:
        nested_dict[name] = {'name': name, 'columns': []}

    # Append the column and its tests to the 'columns' list
    nested_dict[name]['columns'].append({'name': column, 'tests': tests})

# Since we have only one 'name', we extract the value from the nested dictionary
result = nested_dict['ABC_ESTIMATE_REFINED']

print(result)

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Json – CSV data format to nested dictionary

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