Create dataframe based on index from list with different size

Question

What I'm trying to do is to create a dataframe based on a list as index and with a dataframe already determined:

df1:

index   flag   value
3       1      99
5       1      98
7       1      97

index list:

all_index = [1, 2, 3, 4, 5, 6, 7, 8, 9]

then get this output:

df2:

index   flag
1       NaN
2       NaN
3       1
4       NaN
5       1
6       NaN
7       1
8       NaN

I was trying to do it in this way but doesn't works:

df2 = df1.loc[all_index]['flag']

It_is_Chris · Accepted Answer · 2021-06-16 19:51:16Z

1

use reindex

df.set_index('index').reindex(all_index)

answered Jun 16, 2021 at 19:51

It_is_Chris

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Comments

not_speshal · Accepted Answer · 2021-06-16 19:51:26Z

0

You just need reindex:

df2 = df1.reindex(all_index)["flag"]

answered Jun 16, 2021 at 19:51

not_speshal

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SeaBean · Accepted Answer · 2021-06-16 20:07:33Z

0

If you want to get the exact layout (as a dataframe instead of a series), you can use .reindex() in this way:

df2 = df1.reindex(all_index)['flag'].to_frame()

Or

df2 = df1.reindex(all_index)[['flag']]

Result:

print(df2)

   flag
1   NaN
2   NaN
3   1.0
4   NaN
5   1.0
6   NaN
7   1.0
8   NaN
9   NaN

answered Jun 16, 2021 at 20:07

SeaBean

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