I am receiving the error
TypeError: 'filter' object is not subscriptable
When trying to run the following block of code
bonds_unique = {} for bond in bonds_new: if bond[0] < 0: ghost_atom = -(bond[0]) - 1 bond_index = 0 elif bond[1] < 0: ghost_atom = -(bond[1]) - 1 bond_index = 1 else: bonds_unique[repr(bond)] = bond continue if sheet[ghost_atom][1] > r_length or sheet[ghost_atom][1] < 0: ghost_x = sheet[ghost_atom][0] ghost_y = sheet[ghost_atom][1] % r_length image = filter(lambda i: abs(i[0] - ghost_x) < 1e-2 and abs(i[1] - ghost_y) < 1e-2, sheet) bond[bond_index] = old_to_new[sheet.index(image[0]) + 1 ] bond.sort() #print >> stderr, ghost_atom +1, bond[bond_index], image bonds_unique[repr(bond)] = bond # Removing duplicate bonds bonds_unique = sorted(bonds_unique.values())
And
sheet_new = [] bonds_new = [] old_to_new = {} sheet=[] bonds=[]
The error occurs at the line
bond[bond_index] = old_to_new[sheet.index(image[0]) + 1 ]
I apologise that this type of question has been posted on SO many times, but I am fairly new to Python and do not fully understand dictionaries. Am I trying to use a dictionary in a way in which it should not be used, or should I be using a dictionary where I am not using it? I know that the fix is probably very simple (albeit not to me), and I will be very grateful if someone could point me in the right direction.
Once again, I apologise if this question has been answered already
Thanks,
Chris.
I am using Python IDLE 3.3.1 on Windows 7 64-bit.
Methods are not subscriptable objects and therefore cannot be accessed like a list with square brackets. To solve this error, replace the square brackets with the round brackets after the method's name when you are calling it.
The “typeerror: 'int' object is not subscriptable” error is raised when you try to access an integer as if it were a subscriptable object, like a list or a dictionary. To solve this problem, make sure that you do not use slicing or indexing to access values in an integer.
Filter a Python List with filter() The filter(function, iterable) function takes a function as input that takes on argument (a list element) and returns a Boolean value whether this list element should pass the filter. All elements that pass the filter are returned as a new iterable object (a filter object).
TypeError: 'NoneType' object is not subscriptable Solution The best way to resolve this issue is by not assigning the sort() method to any variable and leaving the numbers. sort() as is.
filter()
in python 3 does not return a list, but an iterable filter
object. Use the next()
function on it to get the first filtered item:
bond[bond_index] = old_to_new[sheet.index(next(image)) + 1 ]
There is no need to convert it to a list, as you only use the first value.
Iterable objects like filter()
produce results on demand rather than all in one go. If your sheet
list is very large, it might take a long time and a lot of memory to put all the filtered results into a list, but filter()
only needs to evaluate your lambda
condition until one of the values from sheet
produces a True
result to produce one output. You tell the filter()
object to scan through sheet
for that first value by passing it to the next()
function. You could do so multiple times to get multiple values, or use other tools that take iterables to do more complex things; the itertools
library is full of such tools. The Python for
loop is another such a tool, it too takes values from an iterable one by one.
If you must have access to all filtered results together, because you have to, say, index into the results at will (e.g. because this time your algorithm needed to access index 223, index 17 then index 42) only then convert the iterable object to a list, by using list()
:
image = list(filter(lambda i: ..., sheet))
The ability to access any of the values of an ordered sequence of values is called random access; a list
is such a sequence, and so is a tuple
or a numpy array. Iterables do not provide random access.
Use list
before filter
condtion then it works fine. For me it resolved the issue.
For example
list(filter(lambda x: x%2!=0, mylist))
instead of
filter(lambda x: x%2!=0, mylist)
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