python - Fill a new pandas column with row numbers

Question

I have the following DataFrame data with random index values:

      A   B
100   0   7
203   5   4
5992  0  10
2003  9   8
20   10   5
12    6   2

I would like to add a new column 'C' with row numbers. For example:

      A   B   C
100   0   7   0
203   5   4   1
5992  0  10   2
2003  9   8   3
20   10   5   4
12    6   2   5

Thank you for your help!

question from:https://stackoverflow.com/questions/49574817/fill-a-new-pandas-column-with-row-numbers

Answer 1

Use numpy.arange by length of DataFrame:

df['C'] = np.arange(len(df))

Or yo ucan use DataFrame.shape, thank you @Mehmet Burak Say?c?:

df['C'] = np.arange(df.shape[0])

---

print (df)
       A   B  C
100    0   7  0
203    5   4  1
5992   0  10  2
2003   9   8  3
20    10   5  4
12     6   2  5