Part 3...
On Wed, Jul 29, 2015 at 04:16:58AM -0500, Lissa Hopson wrote:
> following:
>
> 1. Load array x column-wise and array y row-wise
> 2. Multiply x by y to compute array z
> 3. Compute the sum of all elements in column 2 of array x and add it to the
> sum of all elements in row 2 of y (the first row/column is 0, the second is
> 1, etc. That got me at first)
> 4. Compute the smallest element in row 1 of y
> ---using appropriate headings:
> 5. Print out matrices x, y, and z (display on screen, but y'all probably
> get that)
> 6. Print out sum and smallest element
>
> The data with which array x is loaded:
> 1, 3, 5, 7, 9, 0, 2, 4, 6, 8, 0, 1, 2, 3, 4
>
> The data with which array y is loaded:
> 2, 3, 4, 5, 6, 7, 8, 9, 0, 1, 3, 5, 7, 9, 0, 2, 4, 6, 8, 0, 1
>
> Must use functions named as follows:
> LOADX, LOADY, COMPUTEZ, SMALLEST, SUMMATION, OUTDATA
>
> lab5.dat is simply a dat file with the data with which the arrays are
> loaded in one long line, each separated by commas.
> Thanks- in advance- no more comments after the program.
>
> This is what I have thus far:
>
> #Lab #5
> #COSC 1336-31493
> #SUM 2015 NRG
> #Tu/Th 1:15-4:25pm
>
> def main():
> #matrix initialization
> x=[[0,0,0],[0,0,0],[0,0,0],[0,0,0],[0,0,0]]
> y=[[0,0,0,0,0,0,0],[0,0,0,0,0,0,0],[0,0,0,0,0,0,0]]
>
> z=[[0,0,0,0,0,0,0],[0,0,0,0,0,0,0],[0,0,0,0,0,0,0],[0,0,0,0,0,0,0],[0,0,0,0,0,0,0]]
> #file declaration
> infile = open('lab5x.dat','r')
> infile = open('lab5y.dat','r')
> outfile = open('lab5.out', 'w')
> #variables
> sumx = 0
> sumy = 0
> small = 0
> A = 0
> B = 0
> C = 0
>
> #call functions
> LOADX(infile, A)
> LOADY(infile, B)
> COMPUTEZ(A, B, C)
> SUMMATION(A, B)
> SMALLEST(A)
> OUTDATA(file, A, B, C)
> #close files
> infile.close()
> infile.close()
> outfile.close()
> dummy = input('Press any key to continue.')
> #def smallest
> def SMALLEST (B):
> k=0
> s=B[1][k]
> k=k+1
> while (k<7):
> if(s> B[1][k]):
> s=B[1][k]
> k=k+1
I don't think that works at all. There doesn't seem to be any attempt to
check for the smallest value.
Python has a function, min(), which can take a list of values and
returns the smallest of them. So we can do the following:
def SMALLEST(B):
# Return the smallest value in row 1 of matrix B.
get row one
pass it to function min()
return the result
Obviously that's not actual Python code!
Now, remember, your matrix looks like this:
[ [a, b, c, d], # row 0
[e, f, g, h], # row 1
etc.
So getting a row is easy. (Getting a column is trickier.)
the_row = B[1]
result = min(the_row)
return result
will put row 1 into variable the_row, then pass it to min(), and
finally return it.
> def OUTDATA(outfile, x, y, z,SMALLEST,SUMMATION):
> i=0
> j=0
> k=0
> while (k<3):
> print(A[k][0],A[k][1],A[k][2],A[k][3],A[k][4])
> k=k+1
This should be printing the x matrix, but you're using variable A
instead, which as far as I understand it, won't exist. I think the
easiest fix for this problem is to change the name in the function
declaration:
def OUTDATA(outfile, x, y, z, SMALLEST, SUMMATION):
becomes:
def OUTDATA(outfile, A, B, C, SMALLEST, SUMMATION):
Note carefully that you have a clash between the names of the
*function* SMALLEST and the argument SMALLEST. Python won't be
confused, but you may be! I recommend that you change the name in the
function declaration.
> file.write[str(A[k][0])+str(A[k][1])+str(A[k][2])+str(A[k][3])+str(A[k][3])+str(A[k][4])]
Three problems with this one line:
(1) The indentation is lost. Maybe that's just an email thing.
(2) The variable should be called outfile, not file.
(3) You're writing the numbers mashed up together: "12345678"
instead of "12,34,56".
Here's a little trick: you can join a list of strings with commas like
this:
list_of_strings = ['12', '34', '56']
print( ','.join(list_of_strings) )
(except you won't use print, you will write it to a file).
So first you make a list of numbers making up the row:
row = A[k][:]
Convert each item from an int to a str:
row = [str(n) for n in row]
Join with commas:
thestring = ','.join(row)
and finally write it to the file:
# don't forget the newline at the end of each line
outfile.write(thestring + '\n')
> while (j<7):
> print(B[j][0],B[j][1],B[j][2])
> j=j+1
> file.write[str(B[j][0])+str(B[j][1])+str(B[j][2])]
> while (i<7):
> print(C[i][0],C[i][1],C[i][2],C[i][3],C[i][4])
> file.write[str(C[i][0]+C[i][1]+C[i][2]+C[i][3]+C[i][4])]
Again, I believe these will run all the numbers together.
> print ('Summation= ',SUMMATION)
> file.write('Summation= ', SUMMATION)
The print() line is okay, because Python will happily print ints as well
as strings. But you can't write ints to a file, you need to convert to a
string first.
> print ('Smallest= ',SMALLEST)
> file.write('Smallest= ',SMALLEST)
Likewise.
Whew! I'm not sure if I caught everything. There's probably some more
bugs that escaped me, but that should give you a good start to go on
with.
Good luck! Let us know how you go!
--
Steve
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