CS 105 SUMMER WEDNESDAY 3 What to talk about today? From the - PowerPoint PPT Presentation

CS 105 SUMMER – WEDNESDAY 3

What to talk about today?  From the muddiest points  String Formatting... (Including directly looking at the 'X in line' variant)  Return vs print  When do we use lists? Dictionaries?  Boolean expressions I want to touch on  The use of the 'in' operator  The use of short circuiting  Challenge questions you want me to hit? Homework you want me to hit?

Some things not to worry about  Do you need to memorize binary and hex?  No – although binary is super easy with a bit of practice!  Hypothesis testing  Useful, but largely in the reading for interest/relation to functions  "What excel do I need to know?" – When you need it, the reading topic will include it  We get as far as V/HLookUp as far as task complexity, probably second half of next week onward  Tuples and sets – largely deemphasizing them  Although sets do have a use – let's check unique elements of a list!

Quiz 2 comments https://kpwritesb  High level stats: log.files.wordpre ss.com/2017/10  Mean 82%, Median 87% /fireworks-  Pretty good animation-33- 2.gif?w=300&h =294&crop=1  Office hours, office hours  Practice – there is some redundancy! ( Do all the homework )  Better content curve  Quiz 3's programming will focus on conditionals (this week's reading), some expressions  Quiz 4 may dip back into string formatting – but the practice will reflect this!

String Formatting  Let's take a look at HW 4.15 and 4.34  Then let's also try  A string with an integer and a floating point  Looking at the Python string formatting docs  https://docs.python.org/3/library/string.htm l#formatspec

Return vs Print (also function calls)  Return is used to return a value to a place  You touched on modularization in lab yesterday (although lab was a bit large…)  Print just prints output to console  Let's consider – function which calculates price used to calculate a shopping list

List and dictionary usage  You can use lists whenever you want a non-unique stack of "stuff"  In practice, data type tends to be the same, although it does not HAVE to be  This is how Java lists differ from, say, ArrayLists in Java  Dictionary usage is a bit more clear  I have a key for a value  I have a name for an address  I have a user_name for a list of data  I have a company name for a company object (departments, employees, etc.)

What about sets and tuples?  Sets enforce uniqueness, but…  So can lists with in – let's see an example  Tuples I personally only ever use in reference to the data analysis module pandas  I've never used named tuples - they're like mini objects  from collections import namedtuple  Person = namedtuple('Person', 'first_name last_name zip_code')  p1 = Person('Joe', 'Schmoe', '93002')

Boolean Expressions – the use of in  The in operator is used to check for membership in a collection  I'd like to check…  If a string contains 'hello'  If the list ['h', 'ello'] contains 'hello'  if the list, ['hello world', 'I need coffee'] contains 'hello'

Short Circuit  Think about this prompt: "If a number is even and positive, return the number multiplied by 2."  If the number is odd , do you need to check if it is positive?

Short circuit – a more salient example  "If the parameter is a number and it is even, return its square root"  vs  "If something is even and a number, return its square root"

That was my planned content  If there are no questions, we will at least go over…  5.23  5.34  5.37