CODEWITHSUNDEEP
pandas
malp
malp

Reputation: 23

Filling in missing panda lines. With the value of the previous line

I would load one column of a two-column DataFrame with the previous value. Another column with a value of 0.

Original

      A   B
  T
  1  10  11
  3  20  22
  5  15  18

Result

      A   B
  T
  1  10  11
  2  10   0
  3  20  22
  4  20   0
  5  15  18

How can I do this in pandas dataframe ?

Upvotes: 1

Views: 20

Answers (1)

Andrej Kesely
Andrej Kesely

Reputation: 195428

You can do:

mn = df.index.min()
mx = df.index.max()

df = df.reindex(np.arange(mn, mx + 1))
df["A"] = df["A"].ffill()
df["B"] = df["B"].fillna(0)
print(df)

Prints:

      A     B
T            
1  10.0  11.0
2  10.0   0.0
3  20.0  22.0
4  20.0   0.0
5  15.0  18.0

If you want integers, then the last step:

print(df.astype(int))

Prints:

    A   B
T        
1  10  11
2  10   0
3  20  22
4  20   0
5  15  18

Upvotes: 1

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