Python provides builtin functions that explicitly convert between data types. This is commonly known as casting. It is often necessary to cast values when they are used as arguments in a function call. It is generally necessary to cast values whenever a function or other process cannot implicitly convert a given variable to the appropriate datatype. For example when printing a string followed by a numeric type the numeric type must be cast to a string for string concatenation in the print() call to work.

str(variable)  is used to cast numeric data types (integer and float) to strings.