To learn Stata you will nearly have to unlearn SAS. Generate recode age in stata forex in stata forex mindset. There is only one observation in memory at a time. Typically, you can only access the values of variables on the current observation.
The whole dataset is in memory at a time. You can access the values of variables in any observation in the whole dataset. For this reason the RETAIN statement makes no sense in Stata. But the norm is to the variable value of the current observation is used.
A series of statements modify the dataset one observation at a time. One command at a time modifies the dataset one observation at a time, then the next command, etc. In general, you never need to worry about how much memory SAS will require during your session. If you are using a previous version of Stata to version 12, then Stata requires the user to be aware of how much of the computer’s memory will be required to load the dataset into memory.