Hi, I have to combine several datasets of unregular frequency:, as for example, one column contains the security prices for 7 days in a week while second. column contains the security prices only for 5 days in a week . I need (1) to find out the missing dates in second column and (2) then to linearly interpolate the missing data in the second column in order to get balanced data for both columns. Thanks in advance. [[alternative HTML version deleted]]