Type Casting

Type casting Sometimes you need a piece of data converted to a different type In Python you do a typecast to cause that to happen int(3.599) will give 3 – note that it throws away the fraction, does not round it float (4349) will give – it looks the same but remember that it is stored differently in memory float(“23.4”) will give 23.4, but float(“abc”) will give a runtime error x = 5.3 y = int(x) makes y have the value 5, does NOT change x’s value

Type cast for strings str will turn a number into a string. This is handy when you are using functions which require a string as an argument str(3.5) will give “3.5” str(“abc”) will give “abc” – this one is silly but Python allows it. If the data is already a string, why make it a string again?

Typecasting with input function Typecasting is used pretty often with the input function The input function always returns a string If you need the data in the string interpreted as a different type, you have to use a typecast to change it to that type my_num = int(input(“Enter a number “)) This is the shorthand way of writing two statements my_data = input(“Enter a number “)) my_num = int(my_data)

Strongly typed versus weakly typed Python allows one variable to hold many different types of values, one after the other This means the language is weakly typed Languages like C++ and Java are strongly typed. You have to state what type a variable is and it does not change its type for the whole program Types are good to help you avoid errors that involve using the wrong type of data or using the data in an illogical way In Python it is smarter to keep each variable to one type. If you need to use it as a different type, typecast it and put it into a different variable