futures introduction future is thread (or processthat promises to return value in the futureonce the associated behaviour has completed it is thus future value it provides very simple way of firing off behaviour that will either be time consuming to execute or which may be delayed due to expensive operations such as input/output and which could slow down the execution of other elements of program this discusses futures in python the need for future in normal method or function invocationthe method or function is executed in line with the invoking code (the callerhaving to wait until the function or method (the calleereturns only after this is the caller able to continue to the next line of code and execute that in many (mostsituations this is exactly what you want as the next line of code may depend on result returned from the previous line of code etc howeverin some situations the next line of code is independent of the previous line of code for examplelet us assume that we are populating user interface (uithe first line of code may read the name of the user from some external data source (such as databaseand then display it within field in the ui the next line of code may then add todays data to another field in the ui these two lines of code are independent of each other and could be run concurrently/in parallel with each other in this situation we could use either thread or process to run the two lines of code independently of the callerthus achieving level of concurrency and allowing the caller to carry onto the third line of code etc (cspringer nature switzerland ag huntadvanced guide to python programmingundergraduate topics in computer science