I'm new to python, and I'm having trouble resolving this code. I just have to print the position of the string when j equals r. But it prints nothing.
class List():
def __init__(self, l_red, l_erd, r):
self.l_red = "ABCEFGC"
self.l_erd = "DBFEGAC"
self.r = l_red[0]
def posicao(self):
j = self.l_red[0];
while self.l_erd[j] != self.r:
j = j + 1
print(j)
This is a bit hard to understand but I will give it a go.
To begin with you really need to consider using a different name for the class; List is already in python.
To instantiate and use this class you would need to use:
a_variable = List() # or whatever you are going to use
a_variable.posicao()
l_red is a string which can act like a character list, and l_erd is the same. Lists take an integer number (0, 1, 2, 3 ...) and return what was in that place. So what you need to do is something more like:
def posicao(self):
letter_of_interest = "A"
j = 0
for j in range(0, len(self.l_erd):
if letter_of_interest == self.r:
print(j)
break
Now what I have written is just for a single character, and you would use a loop to go through each character of interest, but I will leave that to you.
If you want it to find all the positions where that character exists just remove that break.
There are better methods of doing this, look into just using "ABCDE".index('A') this works.
Related
The task is:
User enters a number, you take 1 number from the left, one from the right and sum it. Then you take the rest of this number and sum every digit in it. then you get two answers. You have to sort them from biggest to lowest and make them into a one solid number. I solved it, but i don't like how it looks like. i mean the task is pretty simple but my code looks like trash. Maybe i should use some more built-in functions and libraries. If so, could you please advise me some? Thank you
a = int(input())
b = [int(i) for i in str(a)]
closesum = 0
d = []
e = ""
farsum = b[0] + b[-1]
print(farsum)
b.pop(0)
b.pop(-1)
print(b)
for i in b:
closesum += i
print(closesum)
d.append(int(closesum))
d.append(int(farsum))
print(d)
for i in sorted(d, reverse = True):
e += str(i)
print(int(e))
input()
You can use reduce
from functools import reduce
a = [0,1,2,3,4,5,6,7,8,9]
print(reduce(lambda x, y: x + y, a))
# 45
and you can just pass in a shortened list instead of poping elements: b[1:-1]
The first two lines:
str_input = input() # input will always read strings
num_list = [int(i) for i in str_input]
the for loop at the end is useless and there is no need to sort only 2 elements. You can just use a simple if..else condition to print what you want.
You don't need a loop to sum a slice of a list. You can also use join to concatenate a list of strings without looping. This implementation converts to string before sorting (the result would be the same). You could convert to string after sorting using map(str,...)
farsum = b[0] + b[-1]
closesum = sum(b[1:-2])
"".join(sorted((str(farsum),str(closesum)),reverse=True))
I actually need help evaluating what is going on with the code which I wrote.
It is meant to function like this:
input: remove_duple('WubbaLubbaDubDub')
output: 'WubaLubaDubDub'
another example:
input: remove_duple('aabbccdd')
output: 'abcd'
I am still a beginner and I would like to know both what is wrong with my code and an easier way to do it. (There are some lines in the code which were part of my efforts to visualize what was happening and debug it)
def remove_duple(string):
to_test = list(string)
print (to_test)
icount = 0
dcount = icount + 1
for char in to_test:
if to_test[icount] == to_test[dcount]:
del to_test[dcount]
print ('duplicate deleted')
print (to_test)
icount += 1
elif to_test[icount] != to_test[dcount]:
print ('no duplicated deleted')
print (to_test)
icount += 1
print ("".join(to_test))
Don't modify a list (e.g. del to_test[dcount]) that you are iterating over. Your iterator will get screwed up. The appropriate way to deal with this would be to create a new list with only the values you want.
A fix for your code could look like:
In []:
def remove_duple(s):
new_list = []
for i in range(len(s)-1): # one less than length to avoid IndexError
if s[i] != s[i+1]:
new_list.append(s[i])
if s: # handle passing in an empty string
new_list.append(s[-1]) # need to add the last character
return "".join(new_list) # return it (print it outside the function)
remove_duple('WubbaLubbaDubDub')
Out[]:
WubaLubaDubDub
As you are looking to step through the string, sliding 2 characters at a time, you can do that simply by ziping the string with itself shifted one, and adding the first character if the 2 characters are not equal, e.g.:
In []:
import itertools as it
def remove_duple(s):
return ''.join(x for x, y in it.zip_longest(s, s[1:]) if x != y)
remove_duple('WubbaLubbaDubDub')
Out[]:
'WubaLubaDubDub'
In []:
remove_duple('aabbccdd')
Out[]:
'abcd'
Note: you need itertools.zip_longest() or you will drop the last character. The default fillvalue of None is fine for a string.
for i in range(1,row):
for j in range(1,col):
if i > j and i != j:
x = Aglo[0][i][0]
y = Aglo[j][0][0]
Aglo[j][i] = offset.myfun(x,y)
Aglo[i][j] = Aglo[j][i]
Aglo[][] is a 2D array, which consists of lists in the first row
offset.myfun() is a function defined elsewhere
This might be a trivial question but i couldn't understand how to use multiprocessing for these nested loops as x,y (used in myfun()) is different for each process(if multiprocessing is used)
Thank you
If I'm reading your code right, you are not overwriting any previously calculated values. If that's true, then you can use multiprocessing. If not, then you can't guarantee that the results from multiprocessing will be in the correct order.
To use something like multiprocessing.Pool, you would need to gather all valid (x, y) pairs to pass to offset.myfun(). Something like this might work (untested):
pairs = [(i, j, Aglo[0][i][0], Aglo[j][0][0]) for i in range(1, row) for j in range(1, col) if i > j and i != j]
# offset.myfun now needs to take a tuple instead of x, y
# it additionally needs to emit i and j in addition to the return value
# e.g. (i, j, result)
p = Pool(4)
results = p.map(offset.myfun, pairs)
# fill in Aglo with the results
for pair in pairs:
i, j, value = pair
Aglo[i][j] = value
Aglo[j][i] = value
You will need to pass in i and j to offset.myfun because otherwise there is no way to know which result goes where. offset.myfun should then return i and j along with the result so you can fill in Aglo appropriately. Hope this helps.
Say I have a list of strings, like so:
strings = ["abc", "def", "ghij"]
Note that the length of a string in the list can vary.
The way you generate a new string is to take one letter from each element of the list, in order. Examples: "adg" and "bfi", but not "dch" because the letters are not in the same order in which they appear in the list. So in this case where I know that there are only three elements in the list, I could fairly easily generate all possible combinations with a nested for loop structure, something like this:
for i in strings[0].length:
for ii in strings[1].length:
for iii in strings[2].length:
print(i+ii+iii)
The issue arises for me when I don't know how long the list of strings is going to be beforehand. If the list is n elements long, then my solution requires n for loops to succeed.
Can any one point me towards a relatively simple solution? I was thinking of a DFS based solution where I turn each letter into a node and creating a connection between all letters in adjacent strings, but this seems like too much effort.
In python, you would use itertools.product
eg.:
>>> for comb in itertools.product("abc", "def", "ghij"):
>>> print(''.join(comb))
adg
adh
adi
adj
aeg
aeh
...
Or, using an unpack:
>>> words = ["abc", "def", "ghij"]
>>> print('\n'.join(''.join(comb) for comb in itertools.product(*words)))
(same output)
The algorithm used by product is quite simple, as can be seen in its source code (Look particularly at function product_next). It basically enumerates all possible numbers in a mixed base system (where the multiplier for each digit position is the length of the corresponding word). A simple implementation which only works with strings and which does not implement the repeat keyword argument might be:
def product(words):
if words and all(len(w) for w in words):
indices = [0] * len(words)
while True:
# Change ''.join to tuple for a more accurate implementation
yield ''.join(w[indices[i]] for i, w in enumerate(words))
for i in range(len(indices), 0, -1):
if indices[i - 1] == len(words[i - 1]) - 1:
indices[i - 1] = 0
else:
indices[i - 1] += 1
break
else:
break
From your solution it seems that you need to have as many for loops as there are strings. For each character you generate in the final string, you need a for loop go through the list of possible characters. To do that you can make recursive solution. Every time you go one level deep in the recursion, you just run one for loop. You have as many level of recursion as there are strings.
Here is an example in python:
strings = ["abc", "def", "ghij"]
def rec(generated, k):
if k==len(strings):
print(generated)
return
for c in strings[k]:
rec(generated + c, k+1)
rec("", 0)
Here's how I would do it in Javascript (I assume that every string contains no duplicate characters):
function getPermutations(arr)
{
return getPermutationsHelper(arr, 0, "");
}
function getPermutationsHelper(arr, idx, prefix)
{
var foundInCurrent = [];
for(var i = 0; i < arr[idx].length; i++)
{
var str = prefix + arr[idx].charAt(i);
if(idx < arr.length - 1)
{
foundInCurrent = foundInCurrent.concat(getPermutationsHelper(arr, idx + 1, str));
}
else
{
foundInCurrent.push(str);
}
}
return foundInCurrent;
}
Basically, I'm using a recursive approach. My base case is when I have no more words left in my array, in which case I simply add prefix + c to my array for every c (character) in my last word.
Otherwise, I try each letter in the current word, and pass the prefix I've constructed on to the next word recursively.
For your example array, I got:
adg adh adi adj aeg aeh aei aej afg afh afi afj bdg bdh bdi
bdj beg beh bei bej bfg bfh bfi bfj cdg cdh cdi cdj ceg ceh
cei cej cfg cfh cfi cfj
I was programming at CodeWars using Kata, when i got this error:
Traceback:
in
in title_case
IndexError: list index out of range
Here is my code:
def title_case(title, minor_words=1):
string = title.split()
outList = []
if minor_words != 1:
split = minor_words.split()
minor = [x.lower() for x in split]
out = ""
for i in range(0, len(string)):
word = ""
for j in range(0,len(string[i])):
elem = ""
elem += string[i][j]
if j == 0:
word += elem.upper()
else:
word += elem.lower()
if i != len(string)-1:
outList.append(word+" ")
else:
outList.append(word)
list = [x.lower() for x in outList]
print ((list[0]))#Just for debug
if minor_words != 1:
for i in range(0, len(outList)):
if (list[i] in minor):
print("OI")#Just for debug
out += list[i]
else:
out += outList[i]
return out
Well, this happened when trying to execute the code, of course!
One way to initialize this function would be:
title_case('a clash of KINGS', 'a an the of')
Well the 0 elemeny exists, but it says it doesn't, I don't know why, because when I write "print(list)" it shows me the elements of list, in this case, "['a', 'clash', 'of', 'kings']".
What can I do?
Okay, so based on reading this code I think the result you desire from:
title_case('a clash of KINGS', 'a an the of') is:
A Clash of Kings
So it looks like you are stepping through a lot of hoops trying to get there. While I was going through the code it took me a while to see what was actually happening. I also took the liberty to make your variables more consistently named. Rather than mixing caseLetter and case_letter randomly I made it consistent. I also made your loops easier to read. Also for the minorWords argument. Might as well have it passed as a list rather than converting it to a list inside the function. Anyway, I hope this is of help.
def titleCase(title, minorWords=[]):
titleList = [x.lower() for x in title.split()]
outList = []
for Word in titleList:
if Word not in minorWords:
Word = Word.capitalize()
outList.append(Word)
return " ".join(outList)
TitleCased = titleCase("a clash of KINGS", ["an", "the", "of"])
print (TitleCased)
Which outputs A Clash of Kings, which I believe, based on your question and how I understood your code is what you wanted to achieve? Or if you include a in your minorWords, it would be:
a Clash of Kings
Regardless, hope this answers your question!