count of rows in pd code example

Example 1: rows count in pand

For a dataframe df, one can use any of the following:

1)len(df.index)
2)df.shape[0]
3)df[df.columns[0]].count() (slowest, but avoids counting NaN values in the first column)

Example 2: pandas count rows in column

>>> df.count(axis='columns')
0    3
1    2
2    3
3    3
4    3
dtype: int64