How do you divide each element in a list by an int?
I just want to divide each element in a list by an int.
myList = [10,20,30,40,50,60,70,80,90] myInt = 10 newList = myList/myInt
This is the error:
TypeError: unsupported operand type(s) for /: 'list' and 'int'
I understand why I am receiving this error. But I am frustrated that I can't find a solution.
newList = [ a/b for a, b in (myList,myInt)]
ValueError: too many values to unpack
newList = [1,2,3,4,5,6,7,8,9]
The following code gives me my expected result:
newList =  for x in myList: newList.append(x/myInt)
But is there an easier/faster way to do this?
The idiomatic way would be to use list comprehension:
myList = [10,20,30,40,50,60,70,80,90] myInt = 10 newList = [x / myInt for x in myList]
or, if you need to maintain the reference to the original list:
myList[:] = [x / myInt for x in myList]
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The way you tried first is actually directly possible with numpy:
import numpy myArray = numpy.array([10,20,30,40,50,60,70,80,90]) myInt = 10 newArray = myArray/myInt
If you do such operations with long lists and especially in any sort of scientific computing project, I would really advise using numpy.
>>> myList = [10,20,30,40,50,60,70,80,90] >>> myInt = 10 >>> newList = map(lambda x: x/myInt, myList) >>> newList [1, 2, 3, 4, 5, 6, 7, 8, 9]
myList = [10,20,30,40,50,60,70,80,90] myInt = 10 newList = [i/myInt for i in myList]
The abstract version can be:
import numpy as np myList = [10, 20, 30, 40, 50, 60, 70, 80, 90] myInt = 10 newList = np.divide(myList, myInt)
myInt=10 myList=[tmpList/myInt for tmpList in range(10,100,10)]