What is the difference between "de" and "por"?
Does "por" also mean in?
2 Answers
Las palabras que mencionas son preposiciones, depende del contexto en donde las utilices.
Revisa el siguiente enlace.
The words are prepositions, they are context dependent, when and where you use it.
Check the next link.
Prepositions in Spanish have so many uses and a lot of the time they don't translate exactly into English,so I think you should go to the reference section and read about prepositions for a full, detailed explanation :D
The dictionary lists more than ten definitions for both por and de.