List index out of range error occurs at the line
if large_l[lg_index] ==small_l[sl_index]:
Here the code works fine when the values of following are,
correctword = "syria"
incorrectword = "siria"
but when assigning value as follows,
correctword = "syria"
incorrectword = "syri"
the above mentioned error has occurred. If could, tell me a way to get rid from this error.
Thank you
correctword = "syria"
incorrectword = "syri"
l1 = list(correctword)
l2 = list(incorrectword)
if len(l1) < len(l2):
large_l= l2
small_l = l1
else:
large_l =l1
small_l = l2
missmatchstart = False
lg_mismatch_start_index = 0
sl_mismatch_start_index = 0
lg_index = 0
sl_index = 0
del_count=0
add_count = 0
sub_count = 0
for l1_item in large_l:
for l2_item in small_l:
if large_l[lg_index] ==small_l[sl_index]:
if missmatchstart == False:
sl_mismatch_start_index = sl_index
lg_mismatch_start_index = lg_index
print(large_l[lg_index])
print("addition ")
print(add_count)
print("deletion ")
print(del_count)
print("substitution ")
print(sub_count)
if lg_index-lg_mismatch_start_index == sl_index-sl_mismatch_start_index:
sub_count += sl_index-sl_mismatch_start_index
lg_index+= 1
sl_index+= 1
elif lg_index-lg_mismatch_start_index > sl_index-sl_mismatch_start_index:
sub_count += sl_index-sl_mismatch_start_index
del_count += ((lg_index-lg_mismatch_start_index) - (sl_index-sl_mismatch_start_index))
lg_index+= 1
sl_index+= 1
elif lg_index-lg_mismatch_start_index < sl_index-sl_mismatch_start_index:
sub_count += lg_index-lg_mismatch_start_index
add_count += ((sl_index-sl_mismatch_start_index) - (lg_index-lg_mismatch_start_index))
lg_index+= 1
sl_index+= 1
missmatchstart = False
break
else:
print(large_l[lg_index])
if(missmatchstart == False):
lg_mismatch_start_index = lg_index
sl_mismatch_start_index = sl_index
print("missmatch large")
print(lg_mismatch_start_index)
print("missmatch small")
print(sl_mismatch_start_index)
missmatchstart =True
sl_index+=1
else:
sl_index+=1
if sl_index== len(small_l)-1:
lg_index +=1
sl_index = sl_mismatch_start_index
#del_count +=1
break
# elif lg_index == sl_index == len(small_l):
# sub_count +=
if lg_index >=len(large_l)-1:
del_count += len(large_l)- lg_index
#elif missmatchstart ==True:
print(add_count)
print(del_count)
print(sub_count)
You probably want to replace the condition on line 24:
if large_l[lg_index] ==small_l[sl_index]:
with:
if l1_item == l2_item:
There might be other bugs there, you should make your code more modular by splitting it into functions (in a reasonable matter) - it will be easier to maintain and debug!
Related
I am attempting to create an exam grading program. I successfully wrote each function to do what I need it to, but when I attempt to execute the entire program, I am running into issues with my return variables not being referenced.
Here is my code for context:
def userinput():
allinputs = []
while True:
try:
results = list(map(int, input('Exam points and exercises completed: ').split(' ')))
allinputs.append(results)
except:
ValueError
break
return allinputs
def points(allinputs):
exampoints = []
exercises = []
exercises_converted = []
gradepoints = []
counter = 0
for i in allinputs:
exampoints.append(i[0])
exercises.append(i[1])
for e in exercises:
exercises_converted.append(e//10)
for p in exampoints:
p2 = exercises_converted[counter]
gradepoints.append(p + p2)
counter += 1
return (gradepoints, exampoints, exercises_converted)
def average(gradepoints):
avg_float = sum(gradepoints) / len(gradepoints)
points_avg = round(avg_float, 1)
return points_avg
def pass_percentage(exercises_converted, exampoints):
failexam = []
passexam = []
passorfail = []
i = 0
while i < len(exampoints):
if exampoints[i] < 10 or exercises_converted[i] + exampoints[i] < 15:
failexam.append("fail")
passorfail.append(0)
else:
passexam.append("pass")
passorfail.append(1)
i += 1
percentage_float = len(passexam)/len(failexam)
percentage = round(percentage_float, 1)
return (percentage, passorfail)
def grades_distribution(passorfail, gradepoints):
grades = []
i = 0
l = 5
while i < len(gradepoints):
if passorfail[i] == 0:
grades.append(0)
elif passorfail[i] != 0 and gradepoints[i] >= 15 and gradepoints[i] <= 17:
grades.append(1)
elif passorfail[i] != 0 and gradepoints[i] >= 18 and gradepoints[i] <= 20:
grades.append(2)
elif passorfail[i] != 0 and gradepoints[i] >= 21 and gradepoints[i] <= 23:
grades.append(3)
elif passorfail[i] != 0 and gradepoints[i] >= 24 and gradepoints[i] <= 27:
grades.append(4)
elif passorfail[i] != 0 and gradepoints[i] >= 28 and gradepoints[i] <= 30:
grades.append(5)
i += 1
while l >= 0:
print(l, ": ", "*" * grades.count(l))
return
userinput()
print("Statistics:")
points(allinputs)
print(f"Points average: {average(gradepoints)}")
print(f"Pass percentage: {pass_percentage(exercises_converted, exampoints)}")
print("Grade distribution")
grades_distribution(passorfail, gradepoints)
I have no problems with the mechanics within each function; rather, my error lies where I try calling each of them from the main function.
The user input() function runs fine, and returns allinputs. However, when the second function points(allinputs) is called, the program states that the argument is undefined.
You should store the return value of a function before passing it as argument.
This should solve your problem
allinputs = userinput()
points(allinputs)
The goal of this code is to find the number of 'sh', 'th', 'wh', and 'ch' digraphs there are in any given sentence. The function keeps returning a 'list index out of range' error, when it seems like everything should be running properly.
exsentence = input("Enter a sentence to scan: ")
slist = list(exsentence.lower())
ch = 0
sh = 0
th = 0
wh = 0
i = 0
'''muppets = slist[i] + slist[i+1]'''
while i < len(slist):
if slist[i] + slist[i+1] == "sh":
sh += 1
elif slist[i] + slist[i+1] == "ch":
ch += 1
elif slist[i] + slist[i+1] == "th":
th += 1
else:
if slist[i] + slist[i+1] == "wh":
wh += 1
i+=1
print("Has {} 'ch' {} 'sh' {} 'th' {} 'wh'".format(ch,sh,th,wh))
Any help is very appriceciated. Thank you.
i+1 will be out of slist bounds. You need to iterate until slist size - 1
while i < len(slist) - 1:
As a side note, for seems to be more appropriate here. Remove i = 0 and i+=1
for i in range(len(slist) - 1):
Use a for loop with range instead:
exsentence = input("Enter a sentence to scan: ")
slist = list(exsentence.lower())
ch = 0
sh = 0
th = 0
wh = 0
i = 0
'''muppets = slist[i] + slist[i+1]'''
for i in range(1,len(slist)):
if slist[i-1] + slist[i] == "sh":
sh += 1
elif slist[i-1] + slist[i] == "ch":
ch += 1
elif slist[i-1] + slist[i] == "th":
th += 1
elif slist[i-1] + slist[i] == "wh":
wh += 1
print(f"Has {ch} 'ch' {sh} 'sh' {th} 'th' {wh} 'wh'")
start the range at 1 and check i-1 against i this way you wont go out of index range
You are checking one position ahead of the current one. Thus you are getting the error of being out of range.
Basically, you are iterating over each position of the array, but you are checking for the nth position against the nth + 1 position. What does happen when you reach the last position? You check it with the next position, which is not defined (otherwise it would not be the last position), and thus get the out of range error.
My suggestion is to not perform the check on the last item against the next one, as there will not be any sequence anymore.
while i < len(slist) - 1:
if slist[i] + slist[i+1] == "sh":
sh += 1
elif slist[i] + slist[i+1] == "ch":
ch += 1
elif slist[i] + slist[i+1] == "th":
th += 1
else:
if slist[i] + slist[i+1] == "wh":
wh += 1
i+=1
I recently decided to try to code "yet another" brainfuck interpreter, but I have a problem. It prints out the wrong numbers, when it should put our hello,world!. Does anyone know why this is happening? Thanks in advance! I cannot figure out why it's doing this. Please help! I am only a beginner. Sorry for the bad coding style, but please don't change the whole thing. I would rather recieve tips.
from copy import copy
import sys
def brainfuckintepreter(program):
# find pairs of brackets
brackets = {}
bbrackets = {}
def findmatchingclosingbracket(ctr):
level = 0
if program[ctr] == '[':
while True:
if program[ctr] == '[':
level += 1
elif program[ctr] == ']':
level -= 1
if level == 0:
return ctr
break
ctr += 1
def findmatchingopeningbracket(ctr):
level = 0
if program[ctr] == ']':
while True:
if program[ctr] == '[':
level -= 1
elif program[ctr] == ']':
level += 1
if level == 0:
return ctr
break
ctr -= 1
"""
ctr = 0
for a in program:
if a == '[':
f = copy(findmatchingclosingbracket(ctr))
brackets[ctr] = f
bbrackets[f] = ctr
ctr += 1
print(brackets)
print(bbrackets)
"""
# running the program
tape = [0] * 3000
pointer = 1500
counter = 0
results = ""
valid = True
while counter != len(program) and valid:
a = program[counter]
# move right
if a == '>':
if pointer == len(tape) - 1:
tape.append(0)
pointer += 1
# move left
elif a == '<':
if pointer == 0:
raise ValueError("On index ", counter, ", the program tried to move to -1 on the tape")
valid = False
return valid
else:
pointer -= 1
# increment
elif a == '+':
if tape[pointer] == 255:
tape[pointer] = 0
else:
tape[pointer] += 1
# decrement
elif a == '-':
if tape[pointer] == 0:
tape[pointer] = 255
else:
tape[pointer] -= 1
# output character
elif a == '.':
t = chr(tape[pointer])
results += t
print(t, end='')
# input character
elif a == ',':
tape[pointer] = ord(sys.stdin.read(1))
# opening bracket
elif a == '[':
if tape[pointer] == 0:
pointer = findmatchingclosingbracket(pointer)
# closing bracket
elif a == ']':
if tape[pointer] != 0:
pointer = findmatchingopeningbracket(counter)
counter += 1
"""
for b in tape:
if b != 0:
print(b)
"""
brainfuckintepreter('++++++++[>++++[>++>+++>+++>+<<<<-]>+>+>->>+[<]<-]>>.>---.+++++++..+++.>>.<-.<.+++.------.--------.>>+.>++.')
Edit:
I changed my code after some revisions, but same problem.
Your loops are the problem.
level = 0
while level > 0:
...
That loop will never be entered. The condition is immediately false (you're setting level to 0, right before checking if it is greater than 0).
You could change that to a do..while loop instead of a while loop (make a while true loop and check the condition at the end to decide whether to break out of the loop or not) and start checking at the current pointer position (include the current [ or ]), not at the next character after it.
Also here:
if tape[pointer] == 0:
pointer = findmatchingclosingbracket(pointer)
you should be passing and updating the program counter, not the tape pointer on the second line. And likewise for the other one just below it.
I am asked to binary search a list of names and if these names start with a particular letter, for example A, then I am to print that name.
I can complete this task by doing much more simple code such as
for i in list:
if i[0] == "A":
print(i)
but instead I am asked to use a binary search and I'm struggling to understand the process behind it. We are given base code which can output the position a given string. My problem is not knowing what to edit so that I can achieve the desired outcome
name_list = ["Adolphus of Helborne", "Aldric Foxe", "Amanita Maleficant", "Aphra the Vicious", "Arachne the Gruesome", "Astarte Hellebore", "Brutus the Gruesome", "Cain of Avernus"]
def bin_search(list, item):
low_b = 0
up_b = len(list) - 1
found = False
while low_b <= up_b and found == False:
midPos = ((low_b + up_b) // 2)
if list[midPos] < item:
low_b = midPos + 1
elif list[midPos] > item:
up_b = midPos - 1
else:
found = True
if found:
print("The name is at positon " + str(midPos))
return midPos
else:
print("The name was not in the list.")
Desired outcome
bin_search(name_list,"A")
Prints all the names starting with A (Adolphus of HelBorne, Aldric Foxe .... etc)
EDIT:
I was just doing some guess and check and found out how to do it. This is the solution code
def bin_search(list, item):
low_b = 0
up_b = len(list) - 1
true_list = []
count = 100
while low_b <= up_b and count > 0:
midPos = ((low_b + up_b) // 2)
if list[midPos][0] == item:
true_list.append(list[midPos])
list.remove(list[midPos])
count -= 1
elif list[midPos] < item:
low_b = midPos + 1
count -= 1
else:
up_b = midPos - 1
count -= 1
print(true_list)
Not too sure if this is what you want as it seems inefficient... as you mention it seems a lot more intuitive to just iterate over the entire list but using binary search i found here i have:
def binary_search(seq, t):
min = 0
max = len(seq) - 1
while True:
if max < min:
return -1
m = (min + max) // 2
if seq[m][0] < t:
min = m + 1
elif seq[m][0] > t:
max = m - 1
else:
return m
index=0
while True:
index=binary_search(name_list,"A")
if index!=-1:
print(name_list[index])
else:
break
del name_list[index]
Output i get:
Aphra the Vicious
Arachne the Gruesome
Amanita Maleficant
Astarte Hellebore
Aldric Foxe
Adolphus of Helborne
You just need to found one item starting with the letter, then you need to identify the range. This approach should be fast and memory efficient.
def binary_search(list,item):
low_b = 0
up_b = len(list) - 1
found = False
midPos = ((low_b + up_b) // 2)
if list[low_b][0]==item:
midPos=low_b
found=True
elif list[up_b][0]==item:
midPos = up_b
found=True
while True:
if found:
break;
if list[low_b][0]>item:
break
if list[up_b][0]<item:
break
if up_b<low_b:
break;
midPos = ((low_b + up_b) // 2)
if list[midPos][0] < item:
low_b = midPos + 1
elif list[midPos] > item:
up_b = midPos - 1
else:
found = True
break
if found:
while True:
if midPos>0:
if list[midPos][0]==item:
midPos=midPos-1
continue
break;
while True:
if midPos<len(list):
if list[midPos][0]==item:
print list[midPos]
midPos=midPos+1
continue
break
else:
print("The name was not in the list.")
the output is
>>> binary_search(name_list,"A")
Adolphus of Helborne
Aldric Foxe
Amanita Maleficant
Aphra the Vicious
Arachne the Gruesome
Astarte Hellebore
I want to make a binary calculator and I have a problem with the subtraction part. Here is my code (I have tried to adapt one for sum that I've found on this website).
maxlen = max(len(s1), len(s2))
s1 = s1.zfill(maxlen)
s2 = s2.zfill(maxlen)
result = ''
carry = 0
i = maxlen - 1
while(i >= 0):
s = int(s1[i]) - int(s2[i])
if s <= 0:
if carry == 0 and s != 0:
carry = 1
result = result + "1"
else:
result = result + "0"
else:
if carry == 1:
result = result + "0"
carry = 0
else:
result = result + "1"
i = i - 1
if carry>0:
result = result + "1"
return result[::-1]
The program works fine with some binaries subtraction but it fails with others.
Can someone please help me because I can't find the mistake? Thanks a lot.
Short answer: Your code is wrong for the case when s1[i] == s2[i] and carry == 1.
Longer answer: You should restructure your code to have three separate cases for s==-1, s==0, and s==1, and then branch on the value of carry within each case:
if s == -1: # 0-1
if carry == 0:
...
else:
...
elif s == 0: # 1-1 or 0-0
if carry == 0:
...
else:
...
else: # 1-0
if carry == 0:
...
else:
...
This way you have a separate block for each possibility, so there is no chance of overlooking a case like you did on your first attempt.
I hope the answer below it helps.
def binarySubstration(str1,str2):
if len(str1) == 0:
return
if len(str2) == 0:
return
str1,str2 = normaliseString(str1,str2)
startIdx = 0
endIdx = len(str1) - 1
carry = [0] * len(str1)
result = ''
while endIdx >= startIdx:
x = int(str1[endIdx])
y = int(str2[endIdx])
sub = (carry[endIdx] + x) - y
if sub == -1:
result += '1'
carry[endIdx-1] = -1
elif sub == 1:
result += '1'
elif sub == 0:
result += '0'
else:
raise Exception('Error')
endIdx -= 1
return result[::-1]
normalising the strings
def normaliseString(str1,str2):
diff = abs((len(str1) - len(str2)))
if diff != 0:
if len(str1) < len(str2):
str1 = ('0' * diff) + str1
else:
str2 = ('0' * diff) + str2
return [str1,str2]