Tutorial 3 Concepts for A1

Transcription

1 CPSC 231 Introduction to Computer Science for Computer Science Majors I Tutoria 3 Concepts for A1 DANNY FISHER dgfisher@ucagary.ca September 23, 2014

2 Agenda script command more detais Submitting using d2 Formua for weighted average Exampes to hep with assignment 1

3 script Makes record of a termina session. script [fiename] Ex: 'script scriptfie' wi record a script in a fie caed 'scriptfie' Defaut fiename: typescript Using backspace wi create garbage characters in a script fie If you make an error just hit enter a few times to make a bank ine

4 Submitting Using D2L

5 Submitting Using D2L

6 Submitting Using D2L

7 Submitting Using D2L

8 Submitting Using D2L

9 Submitting Using D2L

10 Submitting Using D2L

11 Cacuating Weighted Average 6 mini assignments (1% each for 6% tota) 5 assignments (4%, 5%, 6%, 7%, 7% for a tota of 29%) 2 exams (25% midterm, 40% fina for a tota of 65%)

12 Cacuating Weighted Average Suppose a student got 3.0 for a assignments, 2.7 for midterm and 2.0 for fina (3.0 * 0.06) + (3.0 * 0.29) + (2.7 *0.25) + (2.0 * 0.40) = Don't forget to round to two decima paces, so woud be rounded to 2.53

13 Formatting print("%5.2f %-5d " %(1.599, 23)) %5.2f indicates that the foating point number passed in wi be printed with a eft aigned width of at east 5 characters (incuding the '.') and have 2 paces of precision If a number shorter than 5 digits is passed in (23.25) then eading spaces wi be added to create a eft aigned width of at east 5 characters

14 Formatting print("%5.2f %-5d " %(1.599, 23)) %-5d indicates that the integer passed in wi be printed with a right aigned width of at east 5 characters If an integer of ess than 5 digits is passed in traiing spaces wi be added to create a right aigned width of 5 spaces

15 Variabes Variabes are essentiay named containers used to store data which can come in various types Data can come in the form of integers, foats, and strings Integers are non decima numbers (1, 3, 20,...) Foats are decimas numbers (1.0, 3.0, 9.42,...) Strings are any sequence of characters (cat, dog, fgd) they do not have to be actua words

16 Naming Variabes Make sure the name is meaningfu In Python the name must begin with a etter Names are case sensitive but avoid distinguishing two variabes by case Names shoud be a ower case when deaing with a singe word name (width = 2) With mutipe word names distinguish words by capitaizing (bawidth = 2)

17 Naming Variabes Names cannot be Python keywords

18 Constants Constants are variabes whose vaues don't change Unnamed constants, often caed magic numbers, are numerica vaues that appear in programs (num = num + 12, here 12 is an unnamed constant) Named constants are vaues that are referred to by a name ( PI = 3.14) Avoid using unnamed constants uness it is for simpe vaues such as 2 in circumference = 2 * PI * r

19 Operators Python has basic operators such as *, +, and - Division is sighty more compex, when dividing two numbers such as 9/4 you wi get a foat resut Integer division using two back sashes gives you an integer resut, 9//4 = 2 Moduo gives you the remainder of an integer divison, 9%4 = 1

20 Common Syntax Errors Remember to match quotes of the same type, wont match with ' Remember to decare a variabe before using is, before typing print(num) make sure num has been decared

21 Escape Codes \t is the sequence for a tab \n is the sequence for a newine To print characters such as '\' and ' ' we need to provide the escape character '\' Print( \ ) wi print Print( \\ ) wi print \

22 Num = * 3 / 2 print(num) wi print 5 Num = (( 2 + 2) * 3) / 2 print(num) wi print 6 Order of Operation

23 Types Num = print(num) wi print 24 Num = '12' + '12' (String concatenation) print(num) wi print '1212' To convert between types use int(), foat(), and str() int('12') + int('12') = 24 foat(12) + foat(12) = 24.0 str(12) + str(12) = '1212'

24 User Input To get user input use the input() function Input() returns a string so don't forget to convert the input you have obtained from the user num = input( enter your age: ) means num wi contain a string, use int() to convert