I'm newbie in Python and I'm struggling in create a list of sums generated by a for loop.
I got an school assignment where my program have to simulate the scores of a class of blind students in a multiple choice test.
def blindwalk(): # Generates the blind answers in a test with 21 questions
import random
resp = []
gab = ["a","b","c","d"]
for n in range(0,21):
resp.append(random.choice(gab))
return(resp)
def gabarite(): # Generates the official answer key of the tests
import random
answ_gab = []
gab = ["a","b","c","d"]
for n in range(0,21):
answ_gab.append(random.choice(gab))
return(answ_gab)
def class_tests(A): # A is the number of students
alumni = []
A = int(A)
for a in range(0,A):
alumni.append(blindwalk())
return alumni
def class_total(A): # A is the number of students
A = int(A)
official_gab = gabarite()
tests = class_tests(A)
total_score = []*0
for a in range(0,A):
for n in range(0,21):
if tests[a][n] == official_gab[n]:
total_score[a].add(1)
return total_score
When I run the class_total() function, I get this error:
total_score[a].add(1)
IndexError: list index out of range
Question is: How I valuate the scores of each student and create a list with them, because this is what I want to do with the class_total() function.
I also tried
if tests[a][n] == official_gab[n]:
total_score[a] += 1
But I got the same error, so I think I don't fully understand how lists work in Python yet.
Thanks!
(Also, I'm not a English native-speaker, so please tell me if I couldn't be clear enough)
This line:
total_score = []*0
And in fact, any of the following lines:
total_score = []*30
total_score = []*3000
total_score = []*300000000
Cause total_score to be instantiated as an empty list. It doesn't even have a 0th index, in this case! If you'd like to initiate every value to x in a list of length l , the syntax would look more like:
my_list = [x]*l
Alternatively, instead of thinking about the size before-hand, you can use .append instead of trying to access a particular index, as in:
my_list = []
my_list.append(200)
# my_list is now [200], my_list[0] is now 200
my_list.append(300)
# my_list is now [200,300], my_list[0] is still 200 and my_list[1] is now 300
Related
So I am rather new to programming and just recently started with Classes and we are supposed to make a phonebook that can be loaded in seperate text files.
I however keep running into the problem in this section that when I get into the for-loop. It hits a brick wall on
if storage[2] == permaStorage[i].number:
And tells me "IndexError: list index out of range". I am almost certain it is due to permaStorage starts out empty, but even when I attempt to fill it with temporary instances of Phonebook it tells me it out of range. The main reason it is there is to check if a phone number already exists within the permaStorage.
Anyone got a good tip on how to solve this or work around it?
(Sorry if the text is badly written. Just joined this site and not sure on the style)
class Phonebook():
def __init__(self):
self.name = ''
self.number = ''
def Add(name1, number1):
y = Phonebook()
y.name = name1
y.number = number1
return y
def Main():
permaStorage = []
while True:
print " add name number\n lookup name\n alias name newname\n change name number\n save filename\n load filename\n quit\n"
choices = raw_input ("What would you like to do?: ")
storage = choices.split(" ")
if storage[0] == "add":
for i in range(0, len(permaStorage)+1):
if storage[2] == permaStorage[i].number:
print "This number already exists. No two people can have the same phonenumber!\n"
break
if i == len(permaStorage):
print "hej"
try:
tempbox = Add(storage[1], storage[2])
permaStorage.append(tempbox)
except:
raw_input ("Remember to write name and phonenumber! Press any key to continue \n")
I think problem is that permaStorage is empty list and then u try to:
for i in range(0, len(permaStorage)+1):
if storage[2] == permaStorage[i].number:
will cause an error because permaStorage has 0 items but u trying to get first (i=0, permaStorage[0]) item.
I think you should replace second if clause with first one:
for i in range(0, len(permaStorage)+1):
if i == len(permaStorage):
print "hej"
try:
tempbox = Add(storage[1], storage[2])
permaStorage.append(tempbox)
if storage[2] == permaStorage[i].number:
print "This number already exists. No two people can have the same phonenumber!\n"
break
So in this case if perStorage is blank you will append some value and next if clause will be ok.
Indexing starts at zero in python. Hence, a list of length 5 has the last element index as 4 starting from 0. Change range to range(0, len(permastorage))
You should iterate upto the last element of the list, not beyond.
Try -
for i in range(0, len(permaStorage)):
The list of numbers produced in range() is from the start, but not including the end, so range(3) == [0, 1, 2].
So if your list x has length 10, range(0, len(x)) will give you 0 through 9, which is the correct indices of the elements of your list.
Adding 1 to len(x) will produce the range 0 through 10, and when you try to access x[10], it will fail.
doc = "unsorted.txt"
out_fil = "H:\Grade 11\Intro to Computer Science\sorted.txt" # Used in the Windows variation of the program
out_file = "/Applications/Banter" # Used in the Mac variation of the program
import time
def main():
order = False
blank = []
passcount = 0
starttime = time.time()
numlist = CreateList(doc)
while not order:
passcount = passcount + 1
switch = False
switchcount = 0
print "1" # These are test prints to I used to find problems
for x in range (len(numlist)):
print "2" # These are test prints to I used to find problems
if numlist[x] > numlist[x+1]:
temp = numlist[x+1]
numlist[x+1] = numlist[x]
numlist[x] = temp
switchcount = switchcount + 1
switch = True
print "9" # These are test prints to I used to find problems
elif switch == 0:
order = True
CreateFile(numlist)
endtime = time.time()
print "This list required",endtime-starttime,"seconds to sort."
print "This list required",switchcount,"switches to sort."
print "This list required",passcount,"passes to sort."
def CreateList(doc):
sort = open(doc,"r")
numlist = sort.readlines()
sort.close()
for x in range (len(numlist)):
numlist[x] = int(numlist[x].strip())
return numlist
def CreateFile(numlist):
sort = open(doc,"w")
sort.write(str(numlist)+"\n")
sort.close()
return numlist
def List(numlist):
print numlist
main()
The main purpose of my program is to sort a list of integers from a file in order using the bubble sort method, and then put that list into a new file. I'm also detailing the amount of time it takes to perform this as well as the number of passes and switches within the program that it took to sort it completely.
Now, the problem I'm having is that the list index falls out of range because it's comparing x and x+1 of my numlist. But, I need to compare x+1 in order to sort the two integers beside each others within the list. Is there any way I can fix the program so that it'll compare all the integers in the list and not try to compare the space that isn't in the list because of the x+1?
You could make your loop in this way:
for x in range ( len(numlist) -1 ):
Though stackoverflow is a great resource for answers, giving them up for homework assignments feels like cheating. I'll meet you half way: Make your loop run for one less iteration.
I"m trying to scrape Oregon teacher licensure information that looks like this or this(this is publicly available data)
This is my code:
for t in range(0,2): #Refers to txt file with ids
address = 'http://www.tspc.oregon.gov/lookup_application/LDisplay_Individual.asp?id=' + lines2[t]
page = requests.get(address)
tree = html.fromstring(page.text)
count = 0
for license_row in tree.xpath(".//tr[td[1] = 'License Type']/following-sibling::tr[1]"):
license_data = license_row.xpath(".//td/text()")
count = count + 1
if count==1:
ltest1.append(license_data)
if count==2:
ltest2.append(license_data)
if count==3:
ltest3.append(license_data)
with open('teacher_lic.csv', 'wb') as pensionfile:
writer = csv.writer(pensionfile, delimiter="," )
writer.writerow(["Name", "Lic1", "Lic2", "Lic3"])
pen = zip(lname, ltest1, ltest2, ltest3)
for penlist in pen:
writer.writerow(list(penlist))
The problem occurs when this happens: teacher A has 13 licenses and Teacher B has 2. In A my total count = 13 and B = 2. When I get to Teacher B and count equal to 3, I want to say, "if count==3 then ltest3.append(licensure_data) else if count==3 and license_data=='' then license3.append('')" but since there's no count==3 in B there's no way to tell it to append an empty set.
I'd want the output to look like this:
Is there a way to do this? I might be approaching this completely wrong so if someone can point me in another direction, that would be helpful as well.
There's probably a more elegant way to do this but this managed to work pretty well.
I created some blank spaces to fill in when Teacher A has 13 licenses and Teacher B has 2. There were some errors that resulted when the license_row.xpath got to the count==3 in Teacher B. I exploited these errors to create the ltest3.append('').
for t in range(0, 2): #Each txt file contains differing amounts
address = 'http://www.tspc.oregon.gov/lookup_application/LDisplay_Individual.asp?id=' + lines2[t]
page = requests.get(address)
tree = html.fromstring(page.text)
count = 0
test = tree.xpath(".//tr[td[1] = 'License Type']/following-sibling::tr[1]")
difference = 15 - len(test)
for i in range(0, difference):
test.append('')
for license_row in test:
count = count + 1
try:
license_data = license_row.xpath(".//td/text()")
except NameError:
license_data = ''
if license_data=='' and count==1:
ltest1.append('')
if license_data=='' and count==2:
ltest2.append('')
if license_data=='' and count==3:
ltest3.append('')
except AttributeError:
license_data = ''
if count==1 and True:
print "True"
if count==1:
ltest1.append(license_data)
if count==2 and True:
print "True"
if count==2:
ltest2.append(license_data)
if count==3 and True:
print "True"
if count==3:
ltest3.append(license_data)
del license_data
for endorse_row in tree.xpath(".//tr[td = 'Endorsements']/following-sibling::tr"):
endorse_data = endorse_row.xpath(".//td/text()")
lendorse1.append(endorse_data)
I would like to sort a list or an array using python to achive the following:
Say my initial list is:
example_list = ["retg_1_gertg","fsvs_1_vs","vrtv_2_srtv","srtv_2_bzt","wft_3_btb","tvsrt_3_rtbbrz"]
I would like to get all the elements that have 1 behind the first underscore together in one list and the ones that have 2 together in one list and so on. So the result should be:
sorted_list = [["retg_1_gertg","fsvs_1_vs"],["vrtv_2_srtv","srtv_2_bzt"],["wft_3_btb","tvsrt_3_rtbbrz"]]
My code:
import numpy as np
import string
example_list = ["retg_1_gertg","fsvs_1_vs","vrtv_2_srtv","srtv_2_bzt","wft_3_btb","tvsrt_3_rtbbrz"]
def sort_list(imagelist):
# get number of wafers
waferlist = []
for image in imagelist:
wafer_id = string.split(image,"_")[1]
waferlist.append(wafer_id)
waferlist = set(waferlist)
waferlist = list(waferlist)
number_of_wafers = len(waferlist)
# create list
sorted_list = []
for i in range(number_of_wafers):
sorted_list.append([])
for i in range(number_of_wafers):
wafer_id = waferlist[i]
for image in imagelist:
if string.split(image,"_")[1] == wafer_id:
sorted_list[i].append(image)
return sorted_list
sorted_list = sort_list(example_list)
works but it is really awkward and it involves many for loops that slow down everything if the lists are large.
Is there any more elegant way using numpy or anything?
Help is appreciated. Thanks.
I'm not sure how much more elegant this solution is; it is a bit more efficient. You could first sort the list and then go through and filter into final set of sorted lists:
example_list = ["retg_1_gertg","fsvs_1_vs","vrtv_2_srtv","srtv_2_bzt","wft_3_btb","tvsrt_3_rtbbrz"]
sorted_list = sorted(example_list, key=lambda x: x[x.index('_')+1])
result = [[]]
current_num = sorted_list[0][sorted_list[0].index('_')+1]
index = 0
for i in example_list:
if current_num != i[i.index('_')+1]:
current_num = i[i.index('_')+1]
index += 1
result.append([])
result[index].append(i)
print result
If you can make assumptions about the values after the first underscore character, you could clean it up a bit (for example, if you knew that they would always be sequential numbers starting at 1).
For example I have a list with a month and the month number, I want to add in another value in [0][1], [1][1],[2][1] every time I input a new value. I'm thinking of the append function however I'm unsure how to re-code that to make that value to input into the the next list along in the list.
list = [[['Jan'],1], [['Feb'],2],[['Mar'],3]]
def month():
global list
count = 0
while value_count < 3:
value = int(input("Enter a value: "))
if value in range(101):
list[0][1].append(value)
count += 1
else:
print('Try Again.')
month()
I want to result with something like:
list = [[['Jan'],1,54], [['Feb'],2,65],[['Mar'],3,62]]
Where 54, 65 and 62 are random numbers a user has entered.
Please see the comments in the code
# list is a function used by python to create lists,
# do not use builtins' names for your variables
my_list = [[['Jan'],1], [['Feb'],2],[['Mar'],3]]
def month():
# print("Don't use globals!\n"*100)
# you can pass arguments to a function, like in "def mont(my_list)"
global my_list
# cycling on a numerical index is complicated, use this syntax
# instead, meaning "use, in turn, the same name to refer to each
# element of the list"
for element in my_list:
value = int(input("Enter a value: "))
# if value in range(101):
if 1: # always true, the test doesn't work as you expect
element.append(value)
else:
print('Try Again.')
month()
print my_list
you can write the input loop like this
value = 101
while not (0<=value<101):
value = int(input(...)
element.append(value)
this way you'll miss the alternative prompt but it's good enough.