I'm new to here and I'm not really good at English so I apologize for probable future mistakes.
My teacher asked us to write this program with classification... Here is the code
class Matrix:
def __init__(self,lst):
self.mat = lst
self.dim = (len(lst), len(lst[0]))
self.rows=[lst[i][:] for i in range(self.dim[0])]
self.columns=[[lst[i][j] for i in range(self.dim[0])] for j in range(self.dim[1])]
def get(self,i,j):
if (i) <= self.dim[0] and (j) <= self.dim[1]:
return self.mat[i-1][j-1]
else:
print ("index not in matrix!")
return None
def __multList(self,list1,list2):
if len(list1)==len(list2):
return sum([list1[i]*list2[i] for i in range(len(list1))])
def mult(self,other):
matrix=[]
for i in range(len(self.rows)):
rows=[]
for j in range(len(other.columns)):
rows.append(self.__multList(other.columns[j],self.rows[i]))
matrix.append(rows)
return Matrix(matrix)
and this the driver:
from Matrixclass import Matrix
print("For first matrix enter number of row and column respectively: (Ex: 4 5)")
m,n = list(map(int,input().split()))
print("Enter Row values")
mat1 = []
for i in range(m) :
print("Enter row",i + 1,"value:")
row = list(map(int,input().split()))
mat1.append(row)
print("For 2nd matrix enter number of row and column respectively: (Ex: 5 4)")
p,q = list(map(int,input().split()))
print("Enter Row wise values")
mat2 = []
for j in range(p) :
print("Enter row",j + 1,"value:")
row = list(map(int,input().split()))
mat2.append(row)
print("Matrix 1:",mat1)
print("Matrix 2:",mat2)
A = Matrix(mat1)
B = Matrix(mat2)
C=A.mult(B)
print("The Multiplication of two Matrix:\n",C.mat)
And when i run it, i got this error
AttributeError: 'list' object has no attribute 'mult'
Update: Now it works; 🙏thanks
Related
I have this task I need to complete:
"There are N athletes competing in a hammer throw. Each of them made M
throws. The athlete with the highest best throw wins. If there are
several of them, then the one with the best sum of results for all
attempts wins. If there are several of them, the athlete with the
minimum number is considered the winner. Determine the number of the winner of the competition."
I can find highest best throw wins, but I can't find the athlete with the minimum number.
Sample Input:
4 3
4 2 7
1 2 7
1 3 5
4 1 6
Sample Output:
1
My code so far:
row,columns = map(int,input().split())
matrix = [[int(i) for i in input().split()] for j in range(row)]
numbers = []
suma = []
for i in range(row):
numbers.append(matrix[i][0])
sumaa = sum(matrix[i]) - matrix[i][0]
suma.append(sumaa)
new_matrix = [numbers,suma]
print(new_matrix.index(max(new_matrix)))
input = """4 3
4 2 7
1 2 7
1 3 5
4 1 6
"""
def winner(input):
athletes = input.split("\n")
best_throw = max(" ".join(athletes).split(" "))
best_total = max(map(lambda s: sum(list(map(lambda n: int(n) if n != '' else 0, s.split(" ")))), athletes))
best_athletes_indexes = []
for i, athlete in enumerate(athletes):
if best_throw in athlete.split(" ") and sum(map(int, athlete.split(" "))) == best_total:
best_athletes_indexes.append(i)
best_athletes_attempts = list(map(lambda i: len(athletes[i].split(" ")), best_athletes_indexes))
return best_athletes_indexes[best_athletes_attempts.index(min(best_athletes_attempts))]
print(winner(input))
please please please do not ask me to explain this this is the first python i hav written in 2 years. i come from a world of type safety wth
my search history is literally "remove item from list python" the python standard library is strange
It's answer
a = []
b = []
row, columns = map(int, input().split())
for i in range(row):
a.append(list(map(int, input().split())))
for i in range(row):
b.append([max(a[i]), sum(a[i])])
print(b.index(max(b)))
Try this code:
row, columns = map(int, input().split())
matrix = [list(map(int, input().split())) for _ in range(row)]
matrix_max_sum_elms = [[max(row), sum(row)] for row in matrix]
best_athlete_ind = matrix_max_sum_elms.index(max(matrix_max_sum_elms)) + 1
print(best_athlete_ind)
Explanation:
First, we create a list of lists with an input value,
then we create a new list of lists, in which each list contains the maximum value and the sum of the elements of the input values. As a result, we take the index of the list that contains the maximum value and add 1, since indexing starts from 0
As a newbie to python, I've come across a task that I'm having trouble completing. I am supposed to create a new matrix, taking into consideration the original one, inputted by the user, where each element corresponds to the number of adjacent elements greater or equal to the corresponding one in the original matrix. Since English is not my native language, I might not have presented it properly so here is an example:
input:
3x3 matrix
9 14 13
3 0 7
8 15 15
output:
3x3 matrix
2 5 2
1 0 1
2 5 3
So, if it isn't clear, the new matrix determines how many adjacent elements are greater or equal to an element in the original one. 9 is greater than 3 & 0, so that results in "2", 14 is greater than all the adjacent ones so it prints out "5", etc... It also takes diagonals into consideration, of course.
So far, I've got down the input of the original matrix but I'm unsure how to proceed further. I am not someone who's got access to university materials, professors or peer help and my experimentation and search online has been futile so far. I do not need a complete solution, rather than pointers and concept explanation.
This is the code so far:
# matrix input
rOne = int(input("Number of rows:"))
cOne = int(input("Number of columns:"))
# initialize matrix
matrixOne = []
print("Enter elements rowwise:")
# user input
for i in range(rOne): # for loop za redove
a =[]
for j in range(cOne): # for loop za kolone
a.append(int(input()))
matrixOne.append(a)
# print matrix one
for i in range(rOne):
for j in range(cOne):
print(matrixOne[i][j], end = " ")
print()
Here is a function that can do the exact thing:
def adj_matrix(matrixOne, rOne, cOne):
new_lst = []
for i in range(rOne):
a = []
for j in range(cOne):
count = 0
x, y = (i, j) # matrix values here
cells = list(starmap(lambda a,b: (x+a, y+b), product((0,-1,+1), (0,-1,+1)))) # this will find all the adjacent index
filtered_cell = [p for p in cells if (sum(p)>=0 and prod(p)>=0)] # this filters out all the negative indexs
filtered_cell = [p for p in filtered_cell if p[0]<rOne and p[1]<cOne] # this filters out index that are greater than matrix
for z in filtered_cell:
if matrixOne[i][j] >= matrixOne[z[0]][z[1]]:
count += 1
a.append(count-1)
new_lst.append(a)
return new_lst
also import:
from itertools import product, starmap
from math import prod
Actually managed to solve the thing, feels amazing :D
def get_neighbor_elements(current_row, current_col, total_rows, total_cols):
neighbors = []
for i in [-1, 0, 1]: # red pre, isti red, red posle
for j in [-1, 0, 1]: # kolona pre, ista kolona, kolona posle
row = current_row + i
col = current_col + j
if row < 0 or col < 0 or row >= total_rows or col >= total_cols: # preskace se ako se izaslo iz granica matrice
continue
if row == current_row and col == current_col:# ako su red i kolona isti, preskace se(to je taj isti element)
continue
neighbor = [row, col]
neighbors.append(neighbor)
return neighbors
def make_new_matrix(old_matrix):
new_matrix = []
for i in range(len(old_matrix)):
new_matrix.append([])
for i in range(len(old_matrix)): # iteriramo kroz redove stare matrice
for j in range(len(old_matrix[i])): # iteriramo kroz kolone stare matrice
neighbors = get_neighbor_elements(i, j, len(old_matrix), len(old_matrix[i])) # dobavljamo komsije
count = 0
for neighbor in neighbors: # sad gledamo da li je trenutni element veci ili jednak susednim
if old_matrix[i][j] >= old_matrix[neighbor[0]][neighbor[1]]:
count += 1
new_matrix[i].append(count)
return new_matrix
def print_matrix(matrix):
for i in range(len(matrix)):
for j in range(len(matrix[i])):
print(str(matrix[i][j]) + " ", end='')
print()
if __name__ == '__main__':
matrix = [[12, 10], [2, 10]]
print("Old matrix: ")
print_matrix(matrix)
new_matrix = make_new_matrix(matrix)
print("New matrix")
print_matrix(new_matrix)
I am trying to solve 1st step from Numeric Matrix Processor (hyperskill.org). I have to write program (without using numpy) which takes 2 matrix and then if number of rows and number of columns are equal I have to output sum of these 2 matrix. I know that for now number of columns is not used (only in if condition) but it doesn't matter. The problem is "IndexError: list index out of range" after I call summing function. Can someone tell me what am I doing wrong? Thx for helping!
main = []
main2 = []
final = []
mat = []
def reading():
print("rows:")
reading.rows = int(input())
print("columns:")
reading.columns = int(input())
for i in range(reading.rows):
mat = input().split()
mat = list(map(int, mat))
main.append(mat)
return main
def reading2():
print("rows:")
reading2.rows = int(input())
print("columns:")
reading2.columns = int(input())
for i in range(reading2.rows):
mat = input().split()
mat = list(map(int, mat))
main2.append(mat)
return main2
def summing():
if reading.rows == reading2.rows and reading.columns == reading2.columns:
for i in range(reading.rows):
for j in range(reading.columns):
final[i][j] = main[i][j] + main2[i][j]
print(final[j][i], end=" ")
print()
else:
print('ERROR')
reading()
reading2()
summing()
#ADD STRING MATRIX AND NUM MATRIX Fraction(3).limit_denominator(10)from fractions import Fraction
#ONLY WORKS FOR SQUARE ONES RIGHT NOW!
from fractions import Fraction
def make1(nm,x):
if nm[x][x]!=1:
print("Divide R1 by ",Fraction(nm[x][x]).limit_denominator(10))
tempr = multiply(nm[x],1/nm[x][x])
nm[x] = tempr
return nm
def convert(n):
try:
return float(n)
except ValueError:
num, denom = n.split('/')
return float(num) / float(denom)
def convertm(m):
lm = len(m)
lx = len(m[0])
tempn = [0]*lx
temps = [[]]*lm
print(temps)
cnt = 0
for x in m:
tempn = x
for n in x:
temps[cnt].append(str(Fraction(n).limit_denominator(10)))
print(n)
cnt+=1
print(temps)
def mprint(matrix):
s = [[str(e) for e in row] for row in matrix]
lens = [max(map(len, col)) for col in zip(*s)]
fmt = '\t'.join('{{:{}}}'.format(x) for x in lens)
table = [fmt.format(*row) for row in s]
print('\n'.join(table))
def subtract(r1,r2): #r1-r2
tempr = [0]*len(r1)
for x in range (0,len(r1)):
tempr[x] = r1[x]-r2[x]
return tempr
def multiply(r1,n):
tempr = [0]*len(r1)
for x in range (0,len(r1)):
tempr[x] = r1[x]*n
return tempr
def ans(nm):
end = len(nm[0])
cnt = 0
for x in nm:
cnt+=1
print("X",cnt,"=",x[end-1])
equ = int(input("How many equasions are in the linear system? "))
#unk = int(input("How many unkowns are in the linear system? "))
nm = [0] * equ
sm = [0] * equ
for x in range (0,equ):
tempinput = input("Please enter line "+str(x+1)+" of the matrix: ")
templist = [convert(n) for n in tempinput.split()]
nm[x] = templist
sm[x] = tempinput.split()
mprint(nm)
nm = make1(nm,0)
mprint(nm)
for p in range (0,equ-1):
for x in range (p,equ-1):
print("Subtract ",Fraction(nm[x+1][p]).limit_denominator(10),"*",p+1,"by",p+2)
tempr = multiply(nm[p],nm[x+1][p])
nm[x+1] = subtract(tempr,nm[x+1])
print("FIRST X: ",x,"P",x)
mprint(nm)
nm = make1(nm,p+1)
mprint(nm)
#GOIN BACK
for p in range (0,equ-1):
for x in range (0,equ-(p+1)):
print("Subtract ",x,"by",Fraction(nm[x][2-p]).limit_denominator(10),"*",3)
tempr = multiply(nm[2-p],nm[x][2-p])
nm[x]= subtract(nm[x],tempr)
print("SECOND X: ",x,"P",x)
mprint(nm)
ans(nm)
##or x in range (0,equ):
# print()
#g = nm[1][0]-1
#print("")
#tempr = multiply(nm[0],g/nm[0][0])
#nm[0]=tempr
#tempr = subtract(nm[1],nm[0])
#nm[0] = tempr
Pastebin of my code
Ok so where my actual problem is in the unimplemented (because I couldn't get it working) def convertm. What this is supposed to do is take the matrix with numbers (nm) and take every value and convert it into a string as fractions (x/x) if needed and store it in the matrix of strings (sm).
Here is that segment of code I am referencing...
def convertm(m):
lm = len(m)
lx = len(m[0])
tempn = [0]*lx
temps = [[]]*lm
print(temps)
cnt = 0
for x in m:
tempn = x
for n in x:
temps[cnt].append(str(Fraction(n).limit_denominator(10)))
print(n)
cnt+=1
print(temps)
I added some prints in order to try and test what the heck was going on during it. I am getting an output of just the last row being repeated through all rows. I think I don't have a return statement currently just because I have been trying get this to work. Ok so for an example if an array is imported that is...
[ [1,2,3],
[4,5,6],
[7,8,9] ]
It will output (set temps to)
[ ['7','8','9'],
['7','8','9'],
['7','8','9'] ]
I want it to output (set temps to)
[ ['1','2','3'],
['4','5','6'],
['7','8','9'] ]
Also I am using Python 3.3.1
(probably should upgrade to 3.3.3 but that is not what we are discussing!)
I have absolutely no idea why it is doing this and any little bit of help would very appreciated!
THANK YOU
I also apologize if this formatting is horrible I am new to this and I copy/pasted this from another forum I am very desperate to know what is going on here.
The line
temps = [[]]*lm
makes a list of list, where each sublist points to the same list in memory. So, if you modify one, you modify them all. This is why you are seeing the behavior you are seeing.
Change it to
temps = [[] for _ in range(lm)] # xrange on python2
to get different sublists.
Right now I am attempting to code the knapsack problem in Python 3.2. I am trying to do this dynamically with a matrix. The algorithm that I am trying to use is as follows
Implements the memoryfunction method for the knapsack problem
Input: A nonnegative integer i indicating the number of the first
items being considered and a nonnegative integer j indicating the knapsack's capacity
Output: The value of an optimal feasible subset of the first i items
Note: Uses as global variables input arrays Weights[1..n], Values[1...n]
and table V[0...n, 0...W] whose entries are initialized with -1's except for
row 0 and column 0 initialized with 0's
if V[i, j] < 0
if j < Weights[i]
value <-- MFKnapsack(i - 1, j)
else
value <-- max(MFKnapsack(i -1, j),
Values[i] + MFKnapsack(i -1, j - Weights[i]))
V[i, j} <-- value
return V[i, j]
If you run the code below that I have you can see that it tries to insert the weight into the the list. Since this is using the recursion I am having a hard time spotting the problem. Also I get the error: can not add an integer with a list using the '+'. I have the matrix initialized to start with all 0's for the first row and first column everything else is initialized to -1. Any help will be much appreciated.
#Knapsack Problem
def knapsack(weight,value,capacity):
weight.insert(0,0)
value.insert(0,0)
print("Weights: ",weight)
print("Values: ",value)
capacityJ = capacity+1
## ------ initialize matrix F ---- ##
dimension = len(weight)+1
F = [[-1]*capacityJ]*dimension
#first column zeroed
for i in range(dimension):
F[i][0] = 0
#first row zeroed
F[0] = [0]*capacityJ
#-------------------------------- ##
d_index = dimension-2
print(matrixFormat(F))
return recKnap(F,weight,value,d_index,capacity)
def recKnap(matrix, weight,value,index, capacity):
print("index:",index,"capacity:",capacity)
if matrix[index][capacity] < 0:
if capacity < weight[index]:
value = recKnap(matrix,weight,value,index-1,capacity)
else:
value = max(recKnap(matrix,weight,value,index-1,capacity),
value[index] +
recKnap(matrix,weight,value,index-1,capacity-(weight[index]))
matrix[index][capacity] = value
print("matrix:",matrix)
return matrix[index][capacity]
def matrixFormat(*doubleLst):
matrix = str(list(doubleLst)[0])
length = len(matrix)-1
temp = '|'
currChar = ''
nextChar = ''
i = 0
while i < length:
if matrix[i] == ']':
temp = temp + '|\n|'
#double digit
elif matrix[i].isdigit() and matrix[i+1].isdigit():
temp = temp + (matrix[i]+matrix[i+1]).center(4)
i = i+2
continue
#negative double digit
elif matrix[i] == '-' and matrix[i+1].isdigit() and matrix[i+2].isdigit():
temp = temp + (matrix[i]+matrix[i+1]+matrix[i+2]).center(4)
i = i + 2
continue
#negative single digit
elif matrix[i] == '-' and matrix[i+1].isdigit():
temp = temp + (matrix[i]+matrix[i+1]).center(4)
i = i + 2
continue
elif matrix[i].isdigit():
temp = temp + matrix[i].center(4)
#updates next round
currChar = matrix[i]
nextChar = matrix[i+1]
i = i + 1
return temp[:-1]
def main():
print("Knapsack Program")
#num = input("Enter the weights you have for objects you would like to have:")
#weightlst = []
#valuelst = []
## for i in range(int(num)):
## value , weight = eval(input("What is the " + str(i) + " object value, weight you wish to put in the knapsack? ex. 2,3: "))
## weightlst.append(weight)
## valuelst.append(value)
weightLst = [2,1,3,2]
valueLst = [12,10,20,15]
capacity = 5
value = knapsack(weightLst,valueLst,5)
print("\n Max Matrix")
print(matrixFormat(value))
main()
F = [[-1]*capacityJ]*dimension
does not properly initialize the matrix. [-1]*capacityJ is fine, but [...]*dimension creates dimension references to the exact same list. So modifying one list modifies them all.
Try instead
F = [[-1]*capacityJ for _ in range(dimension)]
This is a common Python pitfall. See this post for more explanation.
for the purpose of cache illustration, I generally use a default dict as follows:
from collections import defaultdict
CS = defaultdict(lambda: defaultdict(int)) #if i want to make default vals as 0
###or
CACHE_1 = defaultdict(lambda: defaultdict(lambda: int(-1))) #if i want to make default vals as -1 (or something else)
This keeps me from making the 2d arrays in python on the fly...
To see an answer to z1knapsack using this approach:
http://ideone.com/fUKZmq
def zeroes(n,m):
v=[['-' for i in range(0,n)]for j in range(0,m)]
return v
value=[0,12,10,20,15]
w=[0,2,1,3,2]
v=zeroes(6,5)
def knap(i,j):
global v
if i==0 or j==0:
v[i][j]= 0
elif j<w[i] :
v[i][j]=knap(i-1,j)
else:
v[i][j]=max(knap(i-1,j),value[i]+knap(i-1,j-w[i]))
return v[i][j]
x=knap(4,5)
print (x)
for i in range (0,len(v)):
for j in range(0,len(v[0])):
print(v[i][j],end="\t\t")
print()
print()
#now these calls are for filling all the boxes in the matrix as in the above call only few v[i][j]were called and returned
knap(4,1)
knap(4,2)
knap(4,3)
knap(4,4)
for i in range (0,len(v)):
for j in range(0,len(v[0])):
print(v[i][j],end="\t\t")
print()
print()