TypeError: unsupported operand type(s) for +: 'dict_keys' and 'list' in Python
Dung Do Tien
Oct 22 2021
77
Hello you guys, I am a newbie in Python and I'm also studying more about Python.
I am working with Lamda and the list object dictionary. I have some lines of code as below:
odd_lamda = lambda x: (x + 1) | 1
even_lamda = lambda x: (x + 2) & ~1
object_mapping = {
'RTL': (odd_lamda, 'N'),
'RTR': (even_lamda, 'N'),
'RAL': (odd_lamda, 'R'),
'LTR': (even_lamda, 'L'),
}
ignore = object_mapping.keys() + ['BN', 'PDF', 'B']
remove = object_mapping.keys() + ['BN', 'PDF']
But I get an exception throw TypeError: unsupported operand type(s) for +: 'dict_keys' and 'list' when I run code above.
Traceback (most recent call last):
File "main.py", line 11, in <module>
ignore = object_mapping.keys() + ['BN', 'PDF', 'B']
TypeError: unsupported operand type(s) for +: 'dict_keys' and 'list'
And I am using python 3.x
Anyone can explain it to me?
How can I solve it?
Thanks for any suggestions.
Have 2 answer(s) found.
-
P1
Praween Kumar Oct 23 2021
You got issue in line
11&12. In Python 3.xkeys()method will not return a list string for you, so you need to uselist()method to help convert dictionary to a list string, see example below:ignore = list(object_mapping) + ['BN', 'PDF', 'B'] remove = list(object_mapping) + ['BN', 'PDF']#Output
['RTL', 'RTR', 'RAL', 'LTR', 'BN', 'PDF', 'B'] ['RTL', 'RTR', 'RAL', 'LTR', 'BN', 'PDF']I hope it helpful for you.
-
D0
Dũng Đô La Oct 23 2021
You can use
list()function to help convert dictionary to a list string:odd_lamda = lambda x: (x + 1) | 1 even_lamda = lambda x: (x + 2) & ~1 object_mapping = { 'RTL': (odd_lamda, 'N'), 'RTR': (even_lamda, 'N'), 'RAL': (odd_lamda, 'R'), 'LTR': (even_lamda, 'L'), } ignore = list(object_mapping.keys()) + ['BN', 'PDF', 'B'] remove = list(object_mapping.keys()) + ['BN', 'PDF'] print(ignore) print(remove)#output
['RTL', 'RTR', 'RAL', 'LTR', 'BN', 'PDF', 'B'] ['RTL', 'RTR', 'RAL', 'LTR', 'BN', 'PDF']
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