Split an array in python using indexes from a list

up vote
-2
down vote

favorite

I have a 2d array of size 3 by 7 in numpy:

[[1 2 3 4 5 6 7]
[4 5 6 7 8 9 0] 
[2 3 4 5 6 7 8]]

I also have a list that contains indexes of splitting points:

[1, 3]

Now, I want to split the array using the indexes in the list such that I get:

[[1 2]
[4 5]
[2 3]]

[[ 2 3 4]
[5 6 7]
[3 4 5]]

[[ 4 5 6 7]
[7 8 9 0]
[5 6 7 8]]

How can I do this in python?

edited 2 days ago

jpp

79.8k184695

asked 2 days ago

mrbright

224

add a comment |

up vote
-2
down vote

favorite

I have a 2d array of size 3 by 7 in numpy:

[[1 2 3 4 5 6 7]
[4 5 6 7 8 9 0] 
[2 3 4 5 6 7 8]]

I also have a list that contains indexes of splitting points:

[1, 3]

Now, I want to split the array using the indexes in the list such that I get:

[[1 2]
[4 5]
[2 3]]

[[ 2 3 4]
[5 6 7]
[3 4 5]]

[[ 4 5 6 7]
[7 8 9 0]
[5 6 7 8]]

How can I do this in python?

edited 2 days ago

jpp

79.8k184695

asked 2 days ago

mrbright

224

add a comment |

up vote
-2
down vote

favorite

I have a 2d array of size 3 by 7 in numpy:

[[1 2 3 4 5 6 7]
[4 5 6 7 8 9 0] 
[2 3 4 5 6 7 8]]

I also have a list that contains indexes of splitting points:

[1, 3]

Now, I want to split the array using the indexes in the list such that I get:

[[1 2]
[4 5]
[2 3]]

[[ 2 3 4]
[5 6 7]
[3 4 5]]

[[ 4 5 6 7]
[7 8 9 0]
[5 6 7 8]]

How can I do this in python?

edited 2 days ago

jpp

79.8k184695

asked 2 days ago

mrbright

224

I have a 2d array of size 3 by 7 in numpy:

[[1 2 3 4 5 6 7]
[4 5 6 7 8 9 0] 
[2 3 4 5 6 7 8]]

I also have a list that contains indexes of splitting points:

[1, 3]

Now, I want to split the array using the indexes in the list such that I get:

[[1 2]
[4 5]
[2 3]]

[[ 2 3 4]
[5 6 7]
[3 4 5]]

[[ 4 5 6 7]
[7 8 9 0]
[5 6 7 8]]

How can I do this in python?

python python-3.x list numpy indexing

edited 2 days ago

jpp

79.8k184695

asked 2 days ago

mrbright

224

edited 2 days ago

jpp

79.8k184695

asked 2 days ago

mrbright

224

edited 2 days ago

jpp

79.8k184695

edited 2 days ago

jpp

79.8k184695

edited 2 days ago

jpp

79.8k184695

asked 2 days ago

mrbright

224

asked 2 days ago

mrbright

224

asked 2 days ago

mrbright

224

add a comment |

1 Answer
1

active

oldest

votes

up vote
2
down vote

accepted

You can use a list comprehension with slicing, using zip to extract indices pairwise.

A = np.array([[1, 2, 3, 4, 5, 6, 7],
 [4, 5, 6, 7, 8, 9, 0],
 [2, 3, 4, 5, 6, 7, 8]])

idx = [1, 3]
idx = [0] + idx + [A.shape[1]]

res = [A[:, start: end+1] for start, end in zip(idx, idx[1:])]

print(*res, sep='n'*2)

[[1 2]
 [4 5]
 [2 3]]

[[2 3 4]
 [5 6 7]
 [3 4 5]]

[[4 5 6 7]
 [7 8 9 0]
 [5 6 7 8]]

answered 2 days ago

jpp

79.8k184695

Thank you @jpp, It worked
– mrbright
2 days ago

add a comment |

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1 Answer
1

active

oldest

votes

1 Answer
1

active

oldest

votes

up vote
2
down vote

accepted

You can use a list comprehension with slicing, using zip to extract indices pairwise.

A = np.array([[1, 2, 3, 4, 5, 6, 7],
 [4, 5, 6, 7, 8, 9, 0],
 [2, 3, 4, 5, 6, 7, 8]])

idx = [1, 3]
idx = [0] + idx + [A.shape[1]]

res = [A[:, start: end+1] for start, end in zip(idx, idx[1:])]

print(*res, sep='n'*2)

[[1 2]
 [4 5]
 [2 3]]

[[2 3 4]
 [5 6 7]
 [3 4 5]]

[[4 5 6 7]
 [7 8 9 0]
 [5 6 7 8]]

answered 2 days ago

jpp

79.8k184695

Thank you @jpp, It worked
– mrbright
2 days ago

add a comment |

up vote
2
down vote

accepted

You can use a list comprehension with slicing, using zip to extract indices pairwise.

A = np.array([[1, 2, 3, 4, 5, 6, 7],
 [4, 5, 6, 7, 8, 9, 0],
 [2, 3, 4, 5, 6, 7, 8]])

idx = [1, 3]
idx = [0] + idx + [A.shape[1]]

res = [A[:, start: end+1] for start, end in zip(idx, idx[1:])]

print(*res, sep='n'*2)

[[1 2]
 [4 5]
 [2 3]]

[[2 3 4]
 [5 6 7]
 [3 4 5]]

[[4 5 6 7]
 [7 8 9 0]
 [5 6 7 8]]

answered 2 days ago

jpp

79.8k184695

Thank you @jpp, It worked
– mrbright
2 days ago

add a comment |

up vote
2
down vote

accepted

You can use a list comprehension with slicing, using zip to extract indices pairwise.

A = np.array([[1, 2, 3, 4, 5, 6, 7],
 [4, 5, 6, 7, 8, 9, 0],
 [2, 3, 4, 5, 6, 7, 8]])

idx = [1, 3]
idx = [0] + idx + [A.shape[1]]

res = [A[:, start: end+1] for start, end in zip(idx, idx[1:])]

print(*res, sep='n'*2)

[[1 2]
 [4 5]
 [2 3]]

[[2 3 4]
 [5 6 7]
 [3 4 5]]

[[4 5 6 7]
 [7 8 9 0]
 [5 6 7 8]]

answered 2 days ago

jpp

79.8k184695

You can use a list comprehension with slicing, using zip to extract indices pairwise.

A = np.array([[1, 2, 3, 4, 5, 6, 7],
 [4, 5, 6, 7, 8, 9, 0],
 [2, 3, 4, 5, 6, 7, 8]])

idx = [1, 3]
idx = [0] + idx + [A.shape[1]]

res = [A[:, start: end+1] for start, end in zip(idx, idx[1:])]

print(*res, sep='n'*2)

[[1 2]
 [4 5]
 [2 3]]

[[2 3 4]
 [5 6 7]
 [3 4 5]]

[[4 5 6 7]
 [7 8 9 0]
 [5 6 7 8]]

answered 2 days ago

jpp

79.8k184695

answered 2 days ago

jpp

79.8k184695

answered 2 days ago

jpp

79.8k184695

answered 2 days ago

jpp

79.8k184695

Thank you @jpp, It worked
– mrbright
2 days ago

add a comment |

Thank you @jpp, It worked
– mrbright
2 days ago

Thank you @jpp, It worked
– mrbright
2 days ago

add a comment |

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