How do sort this list using one line? a_list.sort()

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Marshall Lawrence
10 years ago
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1 Review Questions for lists and File (read and write): Make sure to review Midterm 1 and midterm 2, all samples for midterms as well. Review all of the homework, class examples and readings exercises. Make sure to do the readings as well and review all of the class notes. 1) Given: >>> a_list = ["a", "b", "c", "d", "e", "f"] >>> a_list[1:3] ['b', 'c'] >>> a_list[:4] ['a', 'b', 'c', 'd'] >>> a_list[3:] ['d', 'e', 'f'] >>> a_list[:] ['a', 'b', 'c', 'd', 'e', 'f'] >>> a_list[- 1] [ 'f'] >>> a_list[::- 1] ['f', 'e', 'd','c', 'b', a'] How do sort this list using one line? a_list.sort()

1) Given: >>> a_list = ["a", "b", "c", "d", "e", "f"] >>> a_list[1:3] ['b', 'c'] >>> a_list[:4] ['a', 'b', 'c', 'd'] >>> a_list[3:] ['d', 'e',

2 How do you reverse the list using one line? a_list.reverse() How do you add the value 7 to the end of the list? a_list.append(7) How do you find in element a exists in list? If a in a_list: How do you count how many times the value c exists? print(a list.count( f )) How do you remove the value d from list? a_list.remove( d ) How do you find the length of the list? Len(a_list)

append(7) How do you find in element a exists in list?

3 Write the following programs: 1) Call a function to initialize a list randomly (values should be between 1 and 100 inclusive and these values should be divisible evenly by 3 and 5. Then print the list. import random def rand(list): for i in range(1,101,1): # only select random numbers divisible evenly by 3 & 5 if (i%3 ==0 and i%5 ==0): list.append(random.randint(1,10)) print("list in rand function: ", list) def total(list): ''' function to print and compute total of elements in a list ''' tot=0 for item in list: tot += item print("total is: ", tot) num =[] print("list in main: ", num) rand(num)# you are now passing the address in memory where list is stored print("list in main: ", num) total(num)# compute total for all list values/elements

randint(1,10)) print("list in rand function: ", list) def total(list): ''' function to print and compute total of elements in a list ''' tot=0 for item in list: tot += item print("total

4 2) Read a list of words from file, and then search to see if that list includes the word Python. Count how many times Python appears in the file. If the word python appeared in the file, then write python and the number of times the word python appeared into a file? def searchfile(oldfile, newfile): f1 = open(oldfile, "r") f2 = open(newfile, "w") count=0 while True: text = f1.readline() if text == "": break if ("python" in text or "Python" in text): count += 1 f2.write(text) # if you find python then write it to file if count > 0: # print the count of Python in file f2.write("the number of times python appeared in file is : " + str( count) + "\n") f1.close() f2.close() oldfile = "languages.txt" newfile = 'python.txt' searchfile(oldfile, newfile)

def searchfile(oldfile, newfile): f1 = open(oldfile, "r") f2 = open(newfile, "w") count=0 while True: text = f1.

5 3) [Sale application] Write a program that will call a function to decrease all of the list elements values (prices) by 40% when the items are on sale. Then call another function to increase all of the list elements values (prices) by 40% when the sale is over. prices = [100,20,50] print ("Prices from main before function call: ", prices) bf(prices) print ("Prices from main after function bf call: ", prices) orig(prices) print ("Prices from main before function orig call: ", prices) def bf(prices): for i in range (len(prices)): prices[i]= prices[i] *.6 def orig(prices): for i in range (len(prices)): prices[i]= prices[i]/.6

prices = [100,20,50] print ("Prices from main before function call: ", prices) bf(prices) print ("Prices from main after function bf call: ", prices)

6 4) Ask the user to enter integers 1 to 12 for the month. Then, print the month such as January if the user entered 1 and December if the user entered 12. import random monthnumber = input('enter the month using a number from 1-12: ') mnumber= int(monthnumber) months = ['January', 'February', 'March', 'April', 'May', 'June', 'July', 'August', 'September', 'Oct','November', 'December'] print('you picked: '+ printmonth(months,mnumber)) # Select a month at random from months list randommonth = pickrandommonth(months) print("month picked at random is: ", randommonth) def printmonth(months, mnumber): if mnumber < 1 or mnumber > 12: month = 'Error ' else: month = months[mnumber - 1] return month def pickrandommonth(months): rnum = random.randint(1, (len(months)- 1)) ranmonth = months[rnum] return ranmonth

'September', 'Oct','November', 'December'] print('you picked: '+ printmonth(months,mnumber)) # Select a month at random from months list randommonth = pickrandommonth(months) print("month picked at

7 5) Select a word from a list randomly and then ask the user to guess it in three trials. Make sure to give hints on the 2 nd and third trials such as the length of the string and the first character of the word. ''' read files a list of words and then assign all of the words to a list and then choose one word at random from the list. Then play a guess the secret word game in three trials. ''' import random names=[] #Global list # function to read words from file and assign it to a list def readfile(myfile): # read file myfile = open(myfile, "r") for line in myfile: name=line.rstrip('\n') names.append(name) def game(word): #play guess the secret word in 3 trials trial =1 secret="" secret= word.lower() keepgoing= True while(keepgoing): guess = input("try to guess the secret word: ") if ((guess.lower()) == secret): print("congratulations! You won in: ", trial, " trials") keepgoing = False break else:

''' read files a list of words and then assign all of the words to a list and then choose one word at random from the list. Then play a guess the secret word game in three trials.

8 if trial == 3: print("sorry! You lost the game. You used all your three chances", ". The secret word is: ", word) keepgoing = False break else: print("you have ", (3- trial), " trials remaining!") trial += 1 # function to select one word at random from list def selectrandom(): word = random.choice(names) print("word is :", word) return word # printing words.txt (names) print() #call function to read from file words.txt readfile('words.txt') #call function to select a word at random from list word = selectrandom() game(word)

") trial += 1 # function to select one word at random from list def selectrandom(): word = random.

Programming Exercises

s CMPS 5P (Professor Theresa Migler-VonDollen ): Assignment #8 Problem 6 Problem 1 Programming Exercises Modify the recursive Fibonacci program given in the chapter so that it prints tracing information.