Python Programming for Biology: Bioinformatics and Beyond

Figure 5.1.  The definition of abstract functions and their execution within a

program. A function is an encapsulated block of code that is initially defined in an

abstract way. A function generally accepts variable arguments, which would have different

values in different situations, and can pass back or ‘return’ values to the program. A

function can be called into use at any point in a program, once it is defined, and this often

involves sending specific values for the functions’ arguments. Upon calling, the flow of

the program’s execution is diverted to the function, but returns to the original point of the

call when done, often sending back data as one or more return values.