I have q = [[7,2,3],[4,5,6]] and r=[[6,1,2],[3,4,5]]. I need to divide q by the corresponding elements in r. (i.e. [[7/6,2/1,3/2],[4/3,5/4,6/5]])
Output needed B = [[1.16,2,1.5],[1.33,1.25,1.2]]
Code:
B= [[float(j)/float(i) for j in q] for i in r].
However, I keep getting an error : TypeError: float() argument must be a string or a number. I have imported division from future. Any suggestions?
Use zip for bring together the sublists pairwise and then use it again to bring together the corresponding numerators and denominators:
>>> q = [[7,2,3],[4,5,6]]
>>> r = [[6,1,2],[3,4,5]]
>>> [[n/d for n, d in zip(subq, subr)] for subq, subr in zip(q, r)]
[[1.1666666666666667, 2.0, 1.5], [1.3333333333333333, 1.25, 1.2]]
[[float(n)/d for n, d in zip(subq, subr)] for subq, subr in zip(q, r)]
from __future__ import division.You can do:
>>> out=[]
>>> for s1, s2 in zip(q, r):
... inner=[]
... for n, d in zip(s1, s2):
... inner.append(float(n)/d)
... out.append(inner)
...
>>> out
[[1.1666666666666667, 2.0, 1.5], [1.3333333333333333, 1.25, 1.2]]
Or, use numpy:
>>> q=[[7.,2.,3.],[4.,5.,6.]]
>>> r=[[6.,1.,2.],[3.,4.,5.]]
>>> np.array(q)/np.array(r)
array([[ 1.16666667, 2. , 1.5 ],
[ 1.33333333, 1.25 , 1.2 ]])
Or, if you have int literals:
>>> q=[[7,2,3],[4,5,6]]
>>> r=[[6,1,2],[3,4,5]]
>>> np.array(q, dtype=float)/np.array(r)
array([[ 1.16666667, 2. , 1.5 ],
[ 1.33333333, 1.25 , 1.2 ]])