Populate free space between two dates I'm new to data science. I'm trying to increase the time-series length for a special calculation. In the original time-series I have 20 weekly reports and I want to increase the amount of occurrences to 200. Is it ok just to use the range from the first date value to second date value between two neighbor dates?

For example if I have 1 for the first date and I have 5 for the second one, is it fine to populate the empty space between them with 2, 3, 4. Or do I need to use more advanced techniques here?
It depends on the further analysis that you want to perform. Increasing amount of occurrences can significantly effect the properties of your time series data, because you have only 10% of the data available.

In general, this is an interpolation question. There are fundamentally different statistical models that you can use to find the missing data. The Pandas dataframe.interpolate() is a good way to start.