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There are 3 subsets in Spi, each subset contains its sublists and I denoted it as Spi[d][l] (d is the number of subsets and l is the number of sublists).
I want to enter each subset to insert just one specific number which is an element of S_inter into the 3rd, 4th, and 5th (3, 4, 5 are elements of in_inter_job) position of each sublist respectively.
To be more clear, that is inserting number 4 into the first subset, next is number 2 entering to the second subset (2 will be inserted into position 3 of the first sublist, position 4 in the second sublist and 5th position in the last sublist), the do the same for number 6 and the last subset.
S_inter=[4, 2, 6]
in_inter_job=[ 3, 4, 5]
Spi=[[[1, 3, 5, 2, 6], [1, 3, 5, 2, 6], [1, 3, 5, 2, 6]], [[1, 3, 5, 4, 6], [1, 3, 5, 4, 6], [1, 3, 5, 4, 6]], [[1, 3, 5, 4, 2], [1, 3, 5, 4, 2], [1, 3, 5, 4, 2]]]
The result I wanted is like :
Spi=[[[1, 3, 5, 4, 2, 6], [1, 3, 5, 2, 4, 6], [1, 3, 5, 2, 6, 4]], [[1, 3, 5, 2, 4, 6], [1, 3, 5, 4, 2, 6], [1, 3, 5, 4, 6, 2]], [[1, 3, 5, 6, 4, 2], [1, 3, 5, 4, 6, 2], [1, 3, 5, 4, 2, 6]]]
But after I run these for loop:
for d in range(0,len(Spi)):
for k in S_inter:
for l, r in zip(range(len(Spi[d])),in_inter_job):
Spi[d][l].insert(r,k)
if len(Spi[d][l]) == 6:
break
print(" After insert ",Spi)
then I get result:
Spi=[[[1, 3, 5, 6, 6, 6, 2, 2, 2, 4, 2, 6], [1, 3, 5, 6, 6, 6, 2, 2, 2, 4, 2, 6], [1, 3, 5, 6, 6, 6, 2, 2, 2, 4, 2, 6]], [[1, 3, 5, 6, 6, 6, 2, 2, 2, 4, 4, 6], [1, 3, 5, 6, 6, 6, 2, 2, 2, 4, 4, 6], [1, 3, 5, 6, 6, 6, 2, 2, 2, 4, 4, 6]], [[1, 3, 5, 6, 6, 6, 2, 2, 2, 4, 4, 2], [1, 3, 5, 6, 6, 6, 2, 2, 2, 4, 4, 2], [1, 3, 5, 6, 6, 6, 2, 2, 2, 4, 4, 2]]]
Please help me!
Simple nested for loop to insert into each list in Spi at corresponding position in in_inter_job with corresponding value in S_inter:
S_inter=[4, 2, 6]
in_inter_job=[ 3, 4, 5]
Spi=[[[1, 3, 5, 2, 6], [1, 3, 5, 2, 6], [1, 3, 5, 2, 6]], [[1, 3, 5, 4, 6], [1, 3, 5, 4, 6], [1, 3, 5, 4, 6]], [[1, 3, 5, 4, 2], [1, 3, 5, 4, 2], [1, 3, 5, 4, 2]]]
for i, x in enumerate(S_inter):
for j, L in enumerate(Spi[i]):
pos = in_inter_job[j]
L.insert(pos, x)
print(Spi)
Your zip (which is similar to what enumerate above is doing) doesn't work, because it doesn't match your logic. The positions of in_inter_job do not directly correspond with the indexes in S_inter, and so you end up inserting the wrong values, because you're trying to use the same index for both lists.
I have these two matrices:
A = [[2, 7, 3, 6], [3, 3, 4, 4], [6, 9, 5, 3], [4, 2, 1, 7]]
B = [[2, 6, 3, 5], [-1, 2, -3, 1], [2, -5, 7, 3]]
I need to create three matrices A+1st column of B, and so on
So I need this final result:
A1 = [[2, 7, 3, 6, 2], [3, 3, 4, 4, 6], [6, 9, 5, 3, 3], [4, 2, 1, 7, 5]]
A2 = [[2, 7, 3, 6, -1], [3, 3, 4, 4, 2], [6, 9, 5, 3, -3], [4, 2, 1, 7, 7]]
A3 = [[2, 7, 3, 6, 2], [3, 3, 4, 4, -5], [6, 9, 5, 3, 7], [4, 2, 1, 7, 3]]
I start doing the following code, but I only got one of those
for j in range(len(B)):
for i in range(j):
b = B[j][i]
A = [x + [b] for x in A]
print(A)
Output:
[[2, 7, 3, 6], [3, 3, 4, 4], [6, 9, 5, 3], [4, 2, 1, 7]]
[[2, 7, 3, 6, -1], [3, 3, 4, 4, -1], [6, 9, 5, 3, -1], [4, 2, 1, 7, -1]]
[[2, 7, 3, 6, -1, 2, -5], [3, 3, 4, 4, -1, 2, -5], [6, 9, 5, 3, -1, 2, -5], [4, 2, 1, 7, -1, 2, -5]]
Process finished with exit code 0
You can leverage enumerate() to get your output:
A = [[2, 7, 3, 6], [3, 3, 4, 4], [6, 9, 5, 3], [4, 2, 1, 7]]
B = [[2, 6, 3, 5], [-1, 2, -3, 1], [2, -5, 7, 3]]
AA ={}
for idx,inner in enumerate(B):
# add to each a from A the k-th elem of your inner
AA[f"A{idx}"] = [a +[inner[k]] for k,a in enumerate(A)]
print(AA) # stored the lists into a dict
{'A0': [[2, 7, 3, 6, 2], [3, 3, 4, 4, 6], [6, 9, 5, 3, 3], [4, 2, 1, 7, 5]],
'A1': [[2, 7, 3, 6, -1], [3, 3, 4, 4, 2], [6, 9, 5, 3, -3], [4, 2, 1, 7, 1]],
'A2': [[2, 7, 3, 6, 2], [3, 3, 4, 4, -5], [6, 9, 5, 3, 7], [4, 2, 1, 7, 3]]}
As a personal preference I avoid using range(len(...)) where I can - enumerate is cleaner.
If string literals do not work for you, use "A{}".format(idx) instead.
Your code does not work because you coupled the range of i to j
for j in range(len(B)): # j starts as 0,1,2
for i in range(j): # i is doing nothing, 0, 0+1 <-- wrong
This is a possible solution that you can certainly start with:
k = len(A)
D = []
for i in range(len(B)):
D.append([])
for j in range(len(A)):
C = A[j][:k]
C.append(B[i][j])
D[i].append(C)
Make sure to use deepcopy so that they are not all referring to the same object.
A = [[2, 7, 3, 6], [3, 3, 4, 4], [6, 9, 5, 3], [4, 2, 1, 7]]
B = [[2, 6, 3, 5], [-1, 2, -3, 1], [2, -5, 7, 3]]
from copy import deepcopy
A_list = [deepcopy(A) for i in range(3)]
for outer_idx, list_in_b in enumerate(B):
for inner_idx, value in enumerate(list_in_b):
A_list[outer_idx][inner_idx].append(value)
print(A_list)
# Output:
#[[[2, 7, 3, 6, 2], [3, 3, 4, 4, 6], [6, 9, 5, 3, 3], [4, 2, 1, 7, 5]],
# [[2, 7, 3, 6, -1], [3, 3, 4, 4, 2], [6, 9, 5, 3, -3], [4, 2, 1, 7, 1]],
# [[2, 7, 3, 6, 2], [3, 3, 4, 4, -5], [6, 9, 5, 3, 7], [4, 2, 1, 7, 3]]]
In python I have an array of arrays:
[[1,2,3,4,5,6,7,8,6,5,4,3],
[3,4,5,6,7,8,9,5,3,2,4,2],
[3,4,5,6,7,8,9,5,3,2,4,2],
[3,4,5,6,7,8,9,5,3,2,4,2],
[3,4,5,6,7,8,9,5,3,2,4,2]]
And I want to select for each array in array only firs n elements. For example for n == 4 I will get:
[[1,2,3,4],
[3,4,5,6],
[3,4,5,6],
[3,4,5,6],
[3,4,5,6]]
What is the most short code in Python for this?
If you have list of lists then pure python will do:
>>> a = [[1,2,3,4,5,6,7,8,6,5,4,3],
... [3,4,5,6,7,8,9,5,3,2,4,2],
... [3,4,5,6,7,8,9,5,3,2,4,2],
... [3,4,5,6,7,8,9,5,3,2,4,2],
... [3,4,5,6,7,8,9,5,3,2,4,2]]
>>> [x[:4] for x in a]
[[1, 2, 3, 4], [3, 4, 5, 6], [3, 4, 5, 6], [3, 4, 5, 6], [3, 4, 5, 6]]
If it's numpy arrays you can use numpy indexing:
>>> a
array([[1, 2, 3, 4, 5, 6, 7, 8, 6, 5, 4, 3],
[3, 4, 5, 6, 7, 8, 9, 5, 3, 2, 4, 2],
[3, 4, 5, 6, 7, 8, 9, 5, 3, 2, 4, 2],
[3, 4, 5, 6, 7, 8, 9, 5, 3, 2, 4, 2],
[3, 4, 5, 6, 7, 8, 9, 5, 3, 2, 4, 2]])
>>> a[:,:4]
array([[1, 2, 3, 4],
[3, 4, 5, 6],
[3, 4, 5, 6],
[3, 4, 5, 6],
[3, 4, 5, 6]])
You can use list comprehension:
l = [[1,2,3,4,5,6,7,8,6,5,4,3],
[3,4,5,6,7,8,9,5,3,2,4,2],
[3,4,5,6,7,8,9,5,3,2,4,2],
[3,4,5,6,7,8,9,5,3,2,4,2],
[3,4,5,6,7,8,9,5,3,2,4,2]]
result = [el[:4] for el in l]
For example, x = np.random.randint(low=0, high=10, shape=(6,6)) gives me a 6x6 numpy array:
array([[3, 1, 0, 1, 5, 4],
[2, 9, 9, 4, 8, 8],
[2, 3, 4, 3, 2, 9],
[5, 8, 4, 5, 7, 6],
[3, 0, 8, 1, 8, 0],
[6, 7, 1, 9, 0, 5]])
How can I get a list of, say, all 2x3 submatrices? What about non-overlapping ones?
I could code this in myself, but I'm sure this is a common enough operation that it already exists in numpy, I just can't find it.
Listed in this post is a generic approach to get a list of submatrices with given shape. Based on the order of submatrices being row (C-style) or column major (fortran-way), you would have two choices. Here's the implementation with np.reshape , np.transpose and np.array_split -
def split_submatrix(x,submat_shape,order='C'):
p,q = submat_shape # Store submatrix shape
m,n = x.shape
if np.any(np.mod(x.shape,np.array(submat_shape))!=0):
raise Exception('Input array shape is not divisible by submatrix shape!')
if order == 'C':
x4D = x.reshape(-1,p,n/q,q).transpose(0,2,1,3).reshape(-1,p,q)
return np.array_split(x4D,x.size/(p*q),axis=0)
elif order == 'F':
x2D = x.reshape(-1,n/q,q).transpose(1,0,2).reshape(-1,q)
return np.array_split(x2D,x.size/(p*q),axis=0)
else:
print "Invalid output order."
return x
Sample run with a modified sample input -
In [201]: x
Out[201]:
array([[5, 2, 5, 6, 5, 6, 1, 5],
[1, 1, 8, 4, 4, 5, 2, 5],
[4, 1, 6, 5, 6, 4, 6, 1],
[5, 3, 7, 0, 5, 8, 6, 5],
[7, 7, 0, 6, 5, 2, 5, 4],
[3, 4, 2, 5, 0, 7, 5, 0]])
In [202]: split_submatrix(x,(3,4))
Out[202]:
[array([[[5, 2, 5, 6],
[1, 1, 8, 4],
[4, 1, 6, 5]]]), array([[[5, 6, 1, 5],
[4, 5, 2, 5],
[6, 4, 6, 1]]]), array([[[5, 3, 7, 0],
[7, 7, 0, 6],
[3, 4, 2, 5]]]), array([[[5, 8, 6, 5],
[5, 2, 5, 4],
[0, 7, 5, 0]]])]
In [203]: split_submatrix(x,(3,4),order='F')
Out[203]:
[array([[5, 2, 5, 6],
[1, 1, 8, 4],
[4, 1, 6, 5]]), array([[5, 3, 7, 0],
[7, 7, 0, 6],
[3, 4, 2, 5]]), array([[5, 6, 1, 5],
[4, 5, 2, 5],
[6, 4, 6, 1]]), array([[5, 8, 6, 5],
[5, 2, 5, 4],
[0, 7, 5, 0]])]
I need to create a new list merging two lists where one of them is a list of lists. Here's what I need to do:
a = [[2, 1, 4, 5, 0], [3, 6, 5, 4, 8], [2, 1, 4, 7, 8], [3, 4, 9, 5, 6], [7, 5, 2, 1, 1]]
b = [2, 3, 5, 0, 8]
c = []
for indx, item in enumerate(a):
c.append([item, b[indx]])
This generates c as:
[[[2, 1, 4, 5, 0], 2], [[3, 6, 5, 4, 8], 3], [[2, 1, 4, 7, 8], 5], [[3, 4, 9, 5, 6], 0], [[7, 5, 2, 1, 1], 8]]
but I would need it to look like:
[[2, 1, 4, 5, 0, 2], [3, 6, 5, 4, 8, 3], [2, 1, 4, 7, 8, 5], [3, 4, 9, 5, 6, 0], [7, 5, 2, 1, 1], 8]
I've tried adding a * in front of item to unpack the elements but that doesn't work.
Just concatenate the items to create a new list from item and the element from b:
for indx, item in enumerate(a):
c.append(item + [b[indx]])
You can simplify your loop using the zip() function:
for a_item, b_item in zip(a, b):
c.append(a_item + [b_item])
Then move the whole definition of c to a list comprehension:
c = [a_item + [b_item] for a_item, b_item in zip(a, b)]
Demo:
>>> a = [[2, 1, 4, 5, 0], [3, 6, 5, 4, 8], [2, 1, 4, 7, 8], [3, 4, 9, 5, 6], [7, 5, 2, 1, 1]]
>>> b = [2, 3, 5, 0, 8]
>>> [a_item + [b_item] for a_item, b_item in zip(a, b)]
[[2, 1, 4, 5, 0, 2], [3, 6, 5, 4, 8, 3], [2, 1, 4, 7, 8, 5], [3, 4, 9, 5, 6, 0], [7, 5, 2, 1, 1, 8]]
You can make use of zip() function and list comprehension:
>>> a = [[2, 1, 4, 5, 0], [3, 6, 5, 4, 8], [2, 1, 4, 7, 8], [3, 4, 9, 5, 6], [7, 5, 2, 1, 1]]
>>> b = [2, 3, 5, 0, 8]
>>> [elem1 + [elem2] for elem1, elem2 in zip(a, b)]
[[2, 1, 4, 5, 0, 2], [3, 6, 5, 4, 8, 3], [2, 1, 4, 7, 8, 5], [3, 4, 9, 5, 6, 0], [7, 5, 2, 1, 1, 8]]