Cesar Chew at 17:32, 18 October 2013

2013-10-18T17:32:38Z

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<slideshow style="nobleprog" headingmark="⌘" incmark="…" scaled="true" font="Trebuchet MS" >
;title: Python Language Basics- Excercises
;author: Sam Bashton
</slideshow>

=== Language Basics ⌘===

<big>Check all syntactically correct statements</big>

==== Which input statements are correct? ⌘====

# a = raw_input()
# a = raw_input(“enter a number”)
# a = raw_input(enter your name)

==== Which print statements are correct? ⌘====

# print “9” + “9”
# print int(“nine”)
# print str(9) + “nine”
# print 9 + 9
# nine = 9 print nine

==== Which are correct arithmetical operations? ⌘====

# a = 1 * 2
# 2 = 1 + 1
# 5 + 6 = y
# seven = 3 * 4

==== Which are correct variable names? ⌘====

# result
# my.result
# print
# result77

==== Which are correct type conversions? ⌘====

# int(7.0+0.1)
# str(1.2 * 3.4)
# float(“77”+”.0”)
# str( 9 / 0 )

==== Which operations result in 8? ⌘====

# 65 // 8
# 17 % 9
# 2 ** 4
# 64 ** 0.5

==== Which lines are commented? ⌘====

# “””This is a comment”””
# # This is a comment
# // this is a comment
# '''This is a comment'''

=== Data Types ⌘===

<big>Find the matching pairs of expressions and values</big>
<gallery>
File:Selection 002.png
</gallery>

=== Manipulating Strings ⌘===

<big>Write the result of each operation into the fields.</big>

<gallery>
File:Selection 005.png
</gallery>

=== String formatting ⌘===

<big>Find the matching pairs of expressions and values.</big>

<gallery>
File:Selection 006.png
</gallery>

=== Regular Expressions ⌘===

<big>Find the expressions that fit to each row.</big>

<gallery>
File:Selection 007.png
</gallery>

=== Functions and Modules ⌘===

<big>Find the matching pairs.</big>

<gallery>
File:Selection 008.png
</gallery>

=== Manipulating Lists ⌘===

<big>Write the result of each operation into the fields.</big>

<gallery>
File:Selection 009.png
</gallery>

=== Functions operating on lists (1) ⌘===

<big>Write the correct operations to the arrows.</big>

<gallery>
File:Selection 010.png
</gallery>

=== Functions operating on lists (2) ⌘===

<big>Write the correct operations to the arrows</big>

<gallery>
File:Selection 011.png
</gallery>

=== Functions operating on lists (3) ⌘===

<big>Write the result of each operation into the fields.</big>

<gallery>
File:Selection 012.png
</gallery>

=== Manipulating Lists ⌘===

<big>Check the correct answer.</big>

==== What does the list b contain? ⌘====

a = [8,7,6,5,4] b = a[2:4]
# [7,6,5]
# [7,6]
# [6,5]
# [6,5,4]

==== Which of the following code pieces results in ⌘====

# a == [2,4,6]
# a = [1,2,3] * 2
# a = [int(s) for s in “246”]
# a = [x*2 for x in range(3)]
# a = [2**1]+[2**2]+[2**3]

=== Working with Tuples ⌘===

<big>Check all correct answers</big>

==== Which are correct tuples? ⌘====

# ( 1, 2, 3)
# (“Jack” “Knife”)
# ('blue', [0,0,255])
# [ 1, “word” ]

==== What are tuples good for? ⌘====

# Grouping data.
# Managing values that change.
# Running a for loop over them.
# Sorting.

==== On what data types does the len() function work on? ⌘====

# lists
# dictionaries.
# strings.
# tuples.

=== Manipulating Dictionaries ⌘===

<big>Write the result of each operation into the fields.</big>

<gallery>
File:Selection 014.png
</gallery>

=== Manipulating Dictionaries ⌘===

<big>Check the correct answer</big>

==== What do these commands produce? ⌘====

d = {1:'A', 'B':1, 'A':True} print d['A']
# False
# “B”
# True
# 1

==== What do these commands produce? ⌘====

d = {1:'A', 'B':1, 'A':True} print d.has_key('B')
# 1
# True
# 'B'
# False

==== What do these commands produce? ⌘====

d = {1:'A', 'B':1, 'A':True} print d.values()
# True
# ['A',1,True]
# 3
# [1,'B','A']

==== What do these commands produce? ⌘====

d = {1:'A', 'B':1, 'A':True} print d.keys()
# [1,'B','A']
# ['A','B',1]
# [1,'A','B']
# The order may vary.

==== What do these commands produce? ⌘====

d = {1:'A', 'B':1, 'A':True} print d['C']
# None
# 'C'
# an Error
# False

==== What do these commands produce? ⌘====

d = {1:'A', 'B':1, 'A':True} d.setdefault('C',3) print d['C']
# 3
# “C”
# None
# an Error

=== Loops and conditional statements ⌘===

<big>Check the correct statements.</big>

==== Which of these while commands are correct? ⌘====
# while a = 1:
# while a+7:
# while len(c)>10:
# while a and (b-2 == c):
# while b==1
# while s.find('c')>=0:

==== Which of these statements are correct? ⌘====
# 'while' is also called a conditional loop.
# The expression after while may contain function calls.
# It is possible to write endless while loops.
# The colon after while may be omitted.
# The code block after while is executed at least once.

==== What are possible structures of a conditional statement? ⌘====
# if <expression> .. else
# if <expression> .. else if <expression>
# if <expression> .. elif <expression> .. else
# if <expression> .. elif <expression> ..else <expression>
# If <expression>.. else <expression> .. efli

==== Which of these for commands are correct? ⌘====
# for char in “ABCD”:
# for i in range(10):
# for num in (4,6,8):
# for k in 3+7:
# for (i=0; i<10; i+=1):
# for var in seq:

==== Which of these if statements are syntactically correct? ⌘====
# if a and b:
# if len(s) == 23:
# if a but not b<3:
# if a ** 2 >= 49:
# if a != 3:
# if (a and b) or (c and d):

=== Modules and Packages ⌘===

<big>Check the correct answer(s).</big>

==== Which of these import statements are correct? ⌘====
# import re
# import re.sub
# from re import sub
# from re.sub import *
# from .re import *
# from re import *

==== Where does Python look for modules to import ⌘====
# In the sys.path variable.
# In the current working directory.
# In the directory where the current module is.
# In the directory where Python was started.
# In the site-packages folder
# In directories in the PYTHONPATH variable
# In the root directory.

==== Which statements about packages are true? ⌘====
# A package is a directory with modules.
# A package may contain zero modules.
# Packages in site-packages/ are imported automatically.
# A package must contain a __init__.py file.
# A package may contain no code.
# Packages are useless in small programs.

==== Which packages are installed by default? ⌘====
# os – manipulating files and directories.
# psyco – makes Python faster
# time – accessing date and time.
# csv – reads and writes tables.
# numpy – number crunching.
# pdb – Python debugging.

=== While loops ⌘===

<big>Match the expressions for the while loops run the designated number of times</big>

<gallery>
File:Selection 015.png
</gallery>

=== Reading and Writing Files ⌘===

<big>Write Python commands into the fields</big>

<gallery>
File:Selection 016.png
</gallery>

=== Error Handling ⌘===

<big>Check all correct answers</big>

==== Which commands result in an Exception? ⌘====
# f = open(“:::”)
# char = “abc”[7]
# a = (5+9) / (6-(2*3))
# num = [1,2,3][0]
# l = range(10)[:20]
# num = {1:'a'}['a']

==== Which are common types of Exceptions? ⌘====
# ZeroDivisionError
# IOError
# ValueError
# NullPointerException
# KeyError
# InfiniteLoopError

==== Which commands for managing Exceptions exist? ⌘====
# try: … else: ...
# raise ValueError('text')
# try: … except: … error:
# try: … except: ...

=== Working with Files ⌘===

<big>Check all correct answers</big>

==== Which are correct commands working with files? ⌘====
# for line in open(filename):
# f = open(filename,'w')
# open(filename).writelines(out)
# f.close()

==== Which statements about the csv module are correct? ⌘====
# It can save tables of strings and numbers.
# csv reads tables of strings.
# csv cannot handle the quote character.
# Files need to have the .csv suffix.

=== Language Basics ⌘===

<big>
* What is a variable?
* What names may variables have?
* What is an integer?
* What is a string?
* How to assign a variable?
* How to add, substract, and multiply numbers?
* What can be printed with print?
* How can text be read from the keyboard?
* How are comments written in a program?</big>

=== The math module ⌘===

<big>Find the matching pairs of functions and values.</big>

<gallery>
File:Selection 017.png
</gallery>

=== The os module ⌘===

<big>Insert the correct functions into the gaps.</big>

<gallery>
File:Selection 018.png
</gallery>

=== Creating plots ⌘===

<big>Write the result of each operation into the fields.</big>

==== Which of these for commands are necessary to create a figure in matplotlib? ⌘====
# p = plot(x_data,y_data, 'k-')
# title(''Name of the graph')
# xlabel('x axis name')
# axis([0,15,0,10])
# savefig('figure1.png'
# show()

Category:Language Basics - Excercises - Revision history

Cesar Chew at 17:32, 18 October 2013