How to print excel column non null value with python?

I have the following excel sheet:

and want to print column 1 value if the column 2 value is not null. The output should be [1,3].

This the script created by me, but it doesn’t work:

import xlrd
import pandas as pd

filename='test.xlsx'
dataframe = pd.read_excel(filename)
frame = dataframe.loc[dataframe["col2"] !=" "]
df =  frame.iloc[:, 0]

ndarray = df.to_numpy()
print(ndarray)

>Solution :

You can first filter down to nona rows and then show the values of the column you want to show:

dataframe[df['col2'].notna()]['col1'].values