cs61a class note（2）

    Lecture 2 is all about python  variable.As i have learned python programming before.There're still not  too many new things to me.

    Here are some interesting points in this lecture.

    The principle of setting names for the function

    (1)The funcion's name is better in lower case and seperated by the underscore.

    (2)The function's name is better to tell what the operation(ie. print open ...) is or what's the return value(ie. max abs ...) is .

    (3)The parameter's name is better in lower case and seperated by the underscore . But single word is more encouraged !

    (4)The parameter's name is better not use I(captive i) ,l(ell) , O(oh). Because it may confuse the numbers and the letter .

    

    Function as abstraction . After i get a funtion ,i just use it as a blackbox and am not concerned about the intent(How the funciton process the inputs )

    3/26 

since CS61A this part is all about some basic grammer about python ,I pay less attention to this lecture . But that doesn't mean that I would not want to finish this course . Here are some update . 

(1) A function should only have one operation .If a function combines several operations , it'd better be divided into serval functions .

(2) Once you find your code with several parts repeating . Remember the software engineering principle  DRY(DON'T REPEAT YOUR code) . You'd better make these repeating codes into one function . 

(3) Your function should be defined more generally . Think about the function pow & function square . We'd better define function pow , but not square .