The following 'id_vars' are not present in the DataFrame: (list(missing))

Package:

pandas

30911

Exception Class:

KeyError

Raise code

"id_vars must be a list of tuples when columns are a MultiIndex"
            )
        else:
            # Check that `id_vars` are in frame
            id_vars = list(id_vars)
            missing = Index(com.flatten(id_vars)).difference(cols)
            if not missing.empty:
                raise KeyError(
                    "The following 'id_vars' are not present "
                    f"in the DataFrame: {list(missing)}"
                )
    else:
        id_vars = []

    if value_vars is not None:
        if not i

Links to the raise (1)

https://github.com/pandas-dev/pandas/blob/b3e335254f46a526ee3ce9bb757eac4011d9d1fe/pandas/core/reshape/melt.py#L81

Ways to fix

Error code:

import pandas as pd
df = pd.DataFrame({'Name': {0: 'John', 1: 'Bob', 2: 'Shiela'},
                   'Course': {0: 'Masters', 1: 'Graduate', 2: 'Graduate'},
                   'Age': {0: 27, 1: 23, 2: 21}})
# Name is id_vars and Course is value_vars
melted = pd.melt(df, id_vars =['Something'], value_vars =['Course'])  <--#ERROR HERE
print(melted)

That id_vars plays a role as identifier variables. It should be a column name that exists in DataFrame.

Fix code:

import pandas as pd
df = pd.DataFrame({'Name': {0: 'John', 1: 'Bob', 2: 'Shiela'},
                   'Course': {0: 'Masters', 1: 'Graduate', 2: 'Graduate'},
                   'Age': {0: 27, 1: 23, 2: 21}})
# Name is id_vars and Course is value_vars
melted = pd.melt(df, id_vars =['Name'], value_vars =['Course']) 
print(melted)

Jun 28, 2021

anonim 13.0k

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