"term not defined" or "invalid syntax"

[jonathanemil]

Hello,

I am a 1st semester Computer Science student in a Python class. Our current assignment calls for us to read a list from a file, create a 2-dimensional list from the file, and check to see whether or not 2-dim list constitutes a "magic square" (i.e. all the rows, columns and diagonals equal each other when added). We are to create several definitions, and I have had no problem reading from the file, creating the list, and getting the sum of the first row. The next thing I need to do is sum up the other rows and see if they are equal to the first row. If not equal, I return a false and the function ends, if all are equal, I return a True. When I try to call another function (def sum(list, dimensions)) in my "areRowSumsEqua lToSum" function, I am getting a message telling me that the term "dimensions " is not defined, even though i use the same term in the "def sum(list, dimensions)" function. When I try to call sum(list, dimensions) in the definition name, I get an "invalid syntax" error.

The list file looks like this, the first line is the dimensions of the "square", with the list following after a blank space.

3

8
1
6
3
5
7
4
9
2

Here is my code, I appreciate any help, and I apologize if this is a mess. I'm pretty green still.

[CODE=python]
def main():
import string
value = True
while value:
try:
userfile = raw_input("Ente r the file name where the list is located: ")
infile = open(userfile, 'r')
value = False
except IOError:
print "File not found"
dimensions = eval(infile.rea dline())
infile.readline ()
list = construct2dimli st(infile, dimensions)
print sum(list, dimensions)
print areRowSumsEqual ToSum(list, sum(list, dimensions))

def construct2dimli st(infile, dimensions):
outerlist = []
for i in range(dimension s):
sublist = []
for j in range(dimension s):
sublist = sublist + [eval(infile.rea dline())]
outerlist = outerlist + [sublist]
return outerlist

print construct2dimli st(infile, dimensions)
infile.close

def sum(list, dimensions):
rowsum = 0
for i in range(dimension s):
rowsum = rowsum + list[0][i]
return rowsum

def areRowSumsEqual ToSum(list, sum(list, dimensions)):
rowsums = 0
for i in range(1, len(list)):
for j in range(len(list) ):
rowsums = rowsums + list[i][j]
if(sum(list) != rowsums):
return False
return True

main() [/CODE]

Thanks!

edit: i guess the indents don't show up here?

[bartonc]

I can't quote your code here due to a bug in the system, but this should help:

edit: i guess the indents don't show up here?

I've added what are called code tags. Instructions are on the right hand side while posting or replying.

I've marked up your submission, but haven't tested any thing.
I can't stress this enough: Comment everything. You'll like yourself much more in the long run and getting help from others becomes easier, as well.

Have fun:[CODE=python]
def construct2dimli st(infile, dimensions):
"""Build a 2D list using the open file and DIMENSION_TUPLE ????"""
outerlist = []
## for i in range(dimension s):?????????
for i in range(dimension s[0]):
sublist = []
## for j in range(dimension s):???????
for j in range(dimension s[1]):
## sublist = sublist + [eval(infile.rea dline())]
sublist.append( eval(infile.rea dline()))
## outerlist = outerlist + [sublist]
outerlist.appen d(sublist)
return outerlist

#### never executed ####
print construct2dimli st(infile, dimensions)
# don't close here, because in was not opened here, anyway
infile.close

#### Use python built-in function instead
##def sum(list, dimensions):
## rowsum = 0
## for i in range(dimension s):
## rowsum = rowsum + list[0][i]
## return rowsum

def areRowSumsEqual ToSum(list, mustBeANameHere ):
rowsums = 0
## for i in range(1, len(list)): ## Use the list elements instead of an index
for subList in list[1:]: # Might as well slice off the one that was already summed
# that's one way to do it
## for j in range(len(list) ):
## rowsums = rowsums + list[i][j]
## if mustBeANameHere != rowsums:
## return False
if sum(subList) != mustBeANameHere
return False
return True


def main():
import string
value = True
while value:
try:
userfile = raw_input("Ente r the file name where the list is located: ")
infile = open(userfile, 'r')
value = False
except IOError:
print "File not found"
#### STOP EXECUTION ###
return

dimensions = eval(infile.rea dline())
infile.readline () # skip a line
# I like doing this - pass the prepared file to the worker
# but don't use python keywords like 'list', 'dict', etc for variable names (bad practice)
## list = construct2dimli st(infile, dimensions)
a2DList = construct2dimli st(infile, dimensions) # dimensions is presumably a tuple
infile.close

# sum() takes a list, just tell it which part of the array that you want to sum
## theSum = sum(a2DList, dimensions)
theSum = sum(a2DList[0])
print areRowSumsEqual ToSum(list, theSum)

if __name__ == "__main__": # this makes it possible to import this module into others
main()[/CODE]

[jonathanemil]

Thanks for the reply bartonc. I now get this error:

Traceback (most recent call last):
  File "/Users/jonathan/Documents/pythonboard2.py", line 67, in <module>
    main()
  File "/Users/jonathan/Documents/pythonboard2.py", line 59, in main
    a2DList = construct2dimlist(infile, dimensions) # dimensions is presumably a tuple
  File "/Users/jonathan/Documents/pythonboard2.py", line 5, in construct2dimlist
    for i in range(dimensions[0]):
TypeError: 'int' object is unsubscriptable

I was wondering if you could look at my original code and possibly explain why I would be getting an invalid syntax error when I write my definition as:

def areRowSumsEqual ToSum(list, sum(list, dimensions)):

Is it an illegal operation to have "list" in the parameters twice, in two different forms (if that makes sense at all)? As I mentioned before, if I leave out "dimensions ", I get an error telling me that sum has two parameters, and I have left out one, or that "dimensions " is not defined.

Thanks again for the help!

Hmmm...I don't think I "coded" my code correctly for the message board.

[bvdet]

Hello,

I am a 1st semester Computer Science student in a Python class. Our current assignment calls for us to read a list from a file, create a 2-dimensional list from the file, and check to see whether or not 2-dim list constitutes a "magic square" (i.e. all the rows, columns and diagonals equal each other when added). We are to create several definitions, and I have had no problem reading from the file, creating the list, and getting the sum of the first row. The next thing I need to do is sum up the other rows and see if they are equal to the first row. If not equal, I return a false and the function ends, if all are equal, I return a True. When I try to call another function (def sum(list, dimensions)) in my "areRowSumsEqua lToSum" function, I am getting a message telling me that the term "dimensions " is not defined, even though i use the same term in the "def sum(list, dimensions)" function. When I try to call sum(list, dimensions) in the definition name, I get an "invalid syntax" error.

The list file looks like this, the first line is the dimensions of the "square", with the list following after a blank space.

3

8
1
6
3
5
7
4
9
2

Here is my code, I appreciate any help, and I apologize if this is a mess. I'm pretty green still.

[CODE=python]
def main():
import string
value = True
while value:
try:
userfile = raw_input("Ente r the file name where the list is located: ")
infile = open(userfile, 'r')
value = False
except IOError:
print "File not found"
dimensions = eval(infile.rea dline())
infile.readline ()
list = construct2dimli st(infile, dimensions)
print sum(list, dimensions)
print areRowSumsEqual ToSum(list, sum(list, dimensions))

def construct2dimli st(infile, dimensions):
outerlist = []
for i in range(dimension s):
sublist = []
for j in range(dimension s):
sublist = sublist + [eval(infile.rea dline())]
outerlist = outerlist + [sublist]
return outerlist

print construct2dimli st(infile, dimensions)
infile.close

def sum(list, dimensions):
rowsum = 0
for i in range(dimension s):
rowsum = rowsum + list[0][i]
return rowsum

def areRowSumsEqual ToSum(list, sum(list, dimensions)):
rowsums = 0
for i in range(1, len(list)):
for j in range(len(list) ):
rowsums = rowsums + list[i][j]
if(sum(list) != rowsums):
return False
return True

main() [/CODE]

Thanks!

edit: i guess the indents don't show up here?

I made a change to this code snippet of yours:
[code=Python]lst = construct2dimli st(infile, dimensions)
print sum(lst, dimensions)
print areRowSumsEqual ToSum(lst, dimensions)[/code]

You cannot call a function in an argument list. Another change:[code=Python]def areRowSumsEqual ToSum(lst, dimensions):
rowsums = 0
for i in range(1, len(lst)):
for j in range(len(lst)) :
rowsums = rowsums + lst[i][j]
if(sum(lst, dimensions) != rowsums):
return False
return True[/code]

See if your code will execute now.

[bartonc]

Thanks for the reply bartonc. I now get this error:

Traceback (most recent call last):
  File "/Users/jonathan/Documents/pythonboard2.py", line 67, in <module>
    main()
  File "/Users/jonathan/Documents/pythonboard2.py", line 59, in main
    a2DList = construct2dimlist(infile, dimensions) # dimensions is presumably a tuple
  File "/Users/jonathan/Documents/pythonboard2.py", line 5, in construct2dimlist
    for i in range(dimensions[0]):
TypeError: 'int' object is unsubscriptable

Your variable is called "dimentions " with an "s" so I assumed a tuple like

dimensions = (5, 5)

I see now that you assume a square array so take out the subscript "[0]" part.

I was wondering if you could look at my original code and possibly explain why I would be getting an invalid syntax error when I write my definition as:

def areRowSumsEqualToSum(list, sum(list, dimensions)):

Won't work because you must have a name in the argument list so that it may be referred to later in the function. The syntax would be allowed in the function call:

areRowSumsEqualToSum(list, sum(list, dimensions))

but not the definition.

Is it an illegal operation to have "list" in the parameters twice, in two different forms (if that makes sense at all)? As I mentioned before, if I leave out "dimensions ", I get an error telling me that sum has two parameters, and I have left out one, or that "dimensions " is not defined.

Thanks again for the help!

Hmmm...I don't think I "coded" my code correctly for the message board.

Keep trying to get your latest code posted correctly. You have a full hour to get it right. Then it's no big deal for me to fix it after that.

[jonathanemil]

bartonc,

If I could just ask you one more question, you'll be free of me (at least for the rest of this evening). Thank you for your help so far. I have finished my program, however, I am still having a hard time getting my "sum" into each of the different functions in order to compare it with other column/row/diagonal sums. After I calculated the sum in a definition, I figured if I defined "sum" as that definition (sum = sum(list, dimensions)), I'd be able to call that in my other functions easily. It obviously isn't working the way I had hoped-when I print what I hope will be a comparison between "sum" and one of the computed values, they don't equal each other (and they should). In fact, when I try to print "sum" in the other functions, I see "function sum at 0x11132b0", instead of an integer.

Is there any way to get that "sum" into my other definitions without major changes?

Here is my (almost) final code:
[CODE=python]
#magicsquareche cker.py
#This program creates a two-dimensional list of any dimension using
#input from a user-created file. It then evaluates the 2D list to
#determine whether or not it constitues a "Magic Square".

def main():
import string
print "This program constructs a two-dimensional list from a"
print "user-supplied file and checks to see whether the list constitutes"
print "a 'magic square'."
value = True
while value:
try:
userfile = raw_input("Ente r the file name where the list is located: ")
infile = open(userfile, 'r')
value = False
except IOError:
print "File not found"
dimensions = eval(infile.rea dline())
infile.readline ()
list = construct2dimli st(infile, dimensions)
print list
print areRowSumsEqual ToSum(list, sum)
print areColumnSumsEq ualToSum(list, sum)
print isDownDiagonalS umEqualToSum(li st, sum)
print isUpDiagonalSum EqualToSum(list , sum)
print isMagicSquare(l ist)

def construct2dimli st(infile, dimensions):
outerlist = []
for i in range(dimension s):
sublist = []
for j in range(dimension s):
sublist = sublist + [eval(infile.rea dline())]
outerlist = outerlist + [sublist]
return outerlist
construct2dimli st(infile, dimensions)
print areRowSumsEqual ToSum(list, sum)
infile.close

def sum(list, dimensions):
rowsum = 0
for i in range(dimension s):
rowsum = rowsum + list[0][i]
return rowsum

sum = sum(list, dimensions)

def areRowSumsEqual ToSum(list, sum):
otherrowsums = 0
for i in range(1, len(list)):
for j in range(len(list) ):
otherrowsums = otherrowsums + list[i][j]
if(sum != otherrowsums):
return False
return True

def areColumnSumsEq ualToSum(list, sum):
columnsums = 0
for i in range(len(list) ):
for j in range(len(list) ):
columnsums = columnsums + list[j][i]
if(sum != columnsums):
return False
return True

def isDownDiagonalS umEqualToSum(li st, sum):
downdiagonalsum = 0
for i in range(len(list) ):
downdiagonalsum = downdiagonalsum + list[i][i]
if(sum != downdiagonalsum ):
return False
return True

def isUpDiagonalSum EqualToSum(list , sum):
updiagonalsum = 0
for i in range((len(list ))-1, -1, -1):
updiagonalsum = updiagonalsum + list[i][((len(list))-1)-i]
if(sum != updiagonalsum):
return False
return True

def isMagicSquare(l ist):
if(areRowSumsEq ualToSum(list, sum) and areColumnSumsEq ualToSum(list, sum) and isDownDiagonalS umEqualToSum(li st, sum) and isUpDiagonalSum EqualToSum(list , sum)):
return "Yes, the two-dimensional list is a magic square"
return "No, the list does not constitute a magic square."

main()[/CODE]

One more thing, where do I select "Python Code"?

Thanks again!

Jon

[bartonc]

I have to admit being a little disappointed when I saw that you had not made some of the changes that I had suggested. I tried, here, to keep as much of your work as possible, but I can't in good conscience let you create lists by adding them together. I have used list.append() as it should be used.

As for code tag syntax, see the reason for edit at the bottom of your post. The thing is that, if I type it here, it won't show up. You can alway see the raw text of a post when you reply to it, though.[CODE=python]
#magicsquareche cker.py
#This program creates a two-dimensional list of any dimension using
#input from a user-created file. It then evaluates the 2D list to
#determine whether or not it constitues a "Magic Square".

def construct2dimli st(infile, dimensions):
outerlist = []
for i in range(dimension s):
sublist = []
for j in range(dimension s):
sublist.append( eval(infile.rea dline()))
## sublist = sublist + [eval(infile.rea dline())]
outerlist.appen d(sublist)
## outerlist = outerlist + [sublist]
return outerlist

## never executed due to the return above
construct2dimli st(infile, dimensions)
print areRowSumsEqual ToSum(list, sum) # It's bad practice to use built-in names as argument names
infile.close

def my_sum(aList, rowNum): # don't use built-in names for your function names
"""Return the some of a given row"""
## rowsum = 0
## for i in range(dimension s):
## rowsum = rowsum + aList[0][i]
## return rowsum
return sum(aList[rowNum]) # call built-in sum()

## never executed due to the return above
## sum = my_sum(aList, dimensions)

def sum_all(aList):
"""Return the total of all rows in the array"""
return sum([sum(item) for item in aList]) # List comprehentions are very handy

def areRowSumsEqual ToSum(aList, total):
otherrowsums = 0
for i in range(1, len(aList)):
for j in range(len(aList )):
otherrowsums = otherrowsums + aList[i][j]
if(total != otherrowsums):
return False
return True

def areColumnSumsEq ualToSum(aList, total):
columnsums = 0
for i in range(len(aList )):
for j in range(len(aList )):
columnsums = columnsums + aList[j][i]
if(total != columnsums):
return False
return True

def isDownDiagonalS umEqualToSum(aL ist, total):
downdiagonalsum = 0
for i in range(len(aList )):
downdiagonalsum = downdiagonalsum + aList[i][i]
if(total != downdiagonalsum ):
return False
return True

def isUpDiagonalSum EqualToSum(aLis t, total):
updiagonalsum = 0
for i in range((len(aLis t))-1, -1, -1):
updiagonalsum = updiagonalsum + aList[i][((len(aList))-1)-i]
if(total != updiagonalsum):
return False
return True

def isMagicSquare(a List):
if(areRowSumsEq ualToSum(aList, total) and \
areColumnSumsEq ualToSum(aList, total) and \
isDownDiagonalS umEqualToSum(aL ist, total) and \
isUpDiagonalSum EqualToSum(aLis t, total)):
return "Yes, the two-dimensional list is a magic square"
return "No, the list does not constitute a magic square."

def main():
# don't import string unless you really need some constant defined there
## import string
print "This program constructs a two-dimensional list from a"
print "user-supplied file and checks to see whether the list constitutes"
print "a 'magic square'."
value = True
while value:
try:
userfile = raw_input("Ente r the file name where the list is located: ")
infile = open(userfile, 'r')
value = False
except IOError:
print "File not found"
dimensions = eval(infile.rea dline()) # An iteger defining BOTH dimensions
infile.readline () # Skip a line
a2DList = construct2dimli st(infile, dimensions)
### close the file here! ###
infile.close

print a2DList
## Caluculate the sum of the zeroth row ##
rowZeroSum = my_sum(a2DList, 0)
print areRowSumsEqual ToSum(a2DList, rowZeroSum)
print areColumnSumsEq ualToSum(a2DLis t, rowZeroSum)
print isDownDiagonalS umEqualToSum(a2 DList, rowZeroSum)
print isUpDiagonalSum EqualToSum(a2DL ist, rowZeroSum)
print isMagicSquare(a 2DList)


if __name__ == "__main__":

## # used for testing without a file
## from random import randint
## size = 5 # the size of each side of the array
## a2DList = [[randint(0, 50) for i in range(size)] for j in range(size)]

main()[/CODE]

[bartonc]

You may ask all the questions that you like. That's what the Python Forum is here for.

In fact, when I try to print "sum" in the other functions, I see "function sum at 0x11132b0", instead of an integer.

I think that I can put that into terms that are understandable:[CODE=python]
>>> def aFunction(): # everything in python is an object of some sort
... return "hello world" # a function object returns an object of some sort
...
>>> # when you use this syntax:
>>> result = aFunction() # you call the function object and work gets done
>>> print result
hello world
>>> result = aFunction # if you do this by mistake (or in your case not keeping names clear)
>>> print result # you get the function object itself. not the result of the function call
<function aFunction at 0x02F21C30>
>>> [/CODE]

[bvdet]

You may ask all the questions that you like. That's what the Python Forum is here for.

In fact, when I try to print "sum" in the other functions, I see "function sum at 0x11132b0", instead of an integer.

I think that I can put that into terms that are understandable:[CODE=python]
>>> def aFunction(): # everything in python is an object of some sort
... return "hello world" # a function object returns an object of some sort
...
>>> # when you use this syntax:
>>> result = aFunction() # you call the function object and work gets done
>>> print result
hello world
>>> result = aFunction # if you do this by mistake (or in your case not keeping names clear)
>>> print result # you get the function object itself. not the result of the function call
<function aFunction at 0x02F21C30>
>>> [/CODE]

You have done some good work on this thread Barton. I have taken a slightly different approach to this problem. Pass the list to a function. In the function, initialize a set, sum each row, sum each column, sum the two diagonals, and add the results to the set. If the set length is greater than 1, the list is not a magic square and returns False:

def areAllSumsEqual(a2DList):
    sumSet = set()
    # sum each row
    for row in a2DList:
        sumSet.add(sum(row))
        
    # sum each column
    for i in range(len(a2DList)):
        sumSet.add(sum([row[i] for row in a2DList]))
        
    # sum diagonals
    sumSet.add(sum([a2DList[i][i] for i in range(len(a2DList))]))
    indxList = (range(len(a2DList)-1,-1,-1), range(len(a2DList)))
    sumSet.add(sum([a2DList[indxList[0][i]][indxList[1][i]] for i in range(len(a2DList))]))
    
    if len(sumSet) > 1:
        return False
    return True

[jonathanemil]

I have to admit being a little disappointed when I saw that you had not made some of the changes that I had suggested. I tried, here, to keep as much of your work as possible, but I can't in good conscience let you create lists by adding them together. I have used list.append() as it should be used.

The thing is, I'm at a point very early in the game, and some of the changes you made we haven't learned about yet in class. Also, we have very strict assignment specs, what you see in my code is the way my instructor INSISTS on things being done. So while my instructor encouraged us to ask around when we get stuck, I wouldn't feel right about copying portions of your code without really understanding them, and probably wouldn't have gotten credit for them.

But I really do appreciate the input, thank you.

[bartonc]

The thing is, I'm at a point very early in the game, and some of the changes you made we haven't learned about yet in class. Also, we have very strict assignment specs, what you see in my code is the way my instructor INSISTS on things being done. So while my instructor encouraged us to ask around when we get stuck, I wouldn't feel right about copying portions of your code without really understanding them, and probably wouldn't have gotten credit for them.

But I really do appreciate the input, thank you.

Fair enough. I'll go ahead and stick in "best practices" when I see that your instructor is leading you astray (IMO), but won't expect to see them implemented in your re-posts.

Most of all, HAVE FUN WITH PYTHON! It's a really great language.