Hey there, Below there are three different function which return same results but I want to know which one is good for time consuming and if you can explain Big O() also it would be really help full.
#Test1 def string_reverser(our_string): new_string = "" for i in range(len(our_string)): new_string += our_string[(len(our_string)-1)-i] return new_string print ("Pass" if ('retaw' == string_reverser('water')) else "Fail") #Test2 def string_reverser1(our_string): return our_string[::-1] print ("Pass" if ('!noitalupinam gnirts gnicitcarP' == string_reverser1('Practicing string manipulation!')) else "Fail") #Test3 def string_reverser3(our_string): return ("").join([our_string[(len(our_string)-1)-i] for i in range(len(our_string))]) print ("Pass" if ('3432 :si edoc esuoh ehT' == string_reverser3('The house code is: 2343')) else "Fail")
Steven Parker172,267 Points
I'd bet the slice is the fastest (as well as most compact); but if you really want to know for certain, there are a number of benchmarking tools available for Python. But be sure to test your versions using the same string when benchmarking.
That "Big O" notation can be a bit strange at first. Try taking a break from it, and when you review the material again you might get an "Aha!" moment.