Why is my .append () list changing the value of each member variable to a new variable?
In my function, I create unique variables that I want to add to the list. But whenever I add the next variable, the values of all other variables inside the list change to the new one.
Here's my code:
def make_list_of_data_transfer_objects(iFile, eFile, index_of_sheet):
iBook = open_workbook(iFile)
iSheet = iBook.sheet_by_index(0)
eBook = open_workbook(eFile)
eSheet = eBook.sheet_by_index(index_of_sheet)
DataSet = namedtuple('DataSet', 'line_num data_list')
list_objects = []
temp_line_num = 99999
temp_data = [0]*5
for row_index in range(eSheet.nrows):
temp_data[0] = eSheet.cell(row_index,0).value
temp_data[1] = eSheet.cell(row_index,1).value
temp_data[2] = eSheet.cell(row_index,2).value
temp_data[3] = eSheet.cell(row_index,3).value
temp_data[4] = eSheet.cell(row_index,4).value
for row_index2 in range(iSheet.nrows):
if temp_data[0] == iSheet.cell(row_index2,0).value:
temp_line_num = row_index2
temp_object = DataSet(temp_line_num, temp_data)
list_objects.append(temp_object)
#print list_objects #every object is the same
list_objects.sort(key = lambda tup: tup[0]) #sort by line number
return list_objects
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1 answer
Edit
temp_object = DataSet(temp_line_num, temp_data)
to
temp_object = DataSet(temp_line_num, temp_data[:])
or
temp_object = DataSet(temp_line_num, list(temp_data))
By passing temp_data
in DataSet
, you don't create a copy of the list, you just reuse the existing one. By using [:]
or list()
, you create a copy instead.
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