preparing ANOVA table in pandas

Question

Suppose I have a data frame df

column A  column B   column C
large     prom2      34
large     prom1      21
large     prom1      12
large     prom2      8
medium    prom2      5
medium    prom1      7
medium    prom1      12
medium    prom2      12
small     prom1      16
small     prom1      14
small     prom2      12
small     prom1      14

I want to make an analysis of variance (ANOVA), therefore I want to prepare my table. column A value is an index, the value in column B is a new column, and C is a value of the new table. Hence the table should be like this:

col_index  col_prom1  col_prom2
   large      21         34
   large      12         8
   medium     7          5
   medium     12         12
   small      16         12  
   small      14         NaN
   small      14         NaN

values of col_prom1 and col_from2 come from value of column C — Dika, Oct 23 '22 at 21:39

ABC · Answer 1 · 2022-10-23T21:20:08.377

You are looking for pd.DataFrame.pivot():

Working minimal example for your use case is:

df = pd.DataFrame([['large', 'prom2', 34], ['large', 'prom1', 21]], columns=['column A', 'column B', 'column C'])
df = df.pivot_table(index='column A', columns=['column B'], values='column C').reset_index().rename_axis(None, axis=1).rename(columns={df.index.name:'0', 'column A': 'col_index', 'prom1': 'col_prom1', 'prom2': 'col_prom2'})
df

This will yield:

    col_index   col_prom1   col_prom2
0   large       21          34

Disclaimer: This question is a possible duplicate.

Please make sure to not create duplicates.

that methods always show one row. What about other values? – Dika Oct 23 '22 at 21:53 — Dika, Oct 23 '22 at 21:53

preparing ANOVA table in pandas

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