How do I figure out the value which is greater than certain threshold in a matrix?

-2

Assume that I have a matrix:

a = [[4,7,2],[0,1,4],[4,5,6]]

And I want to get

b = [0, 1]

c = [[2],[0,1]]

b = [0,1] because the inner lists of a at position 0 and 1 contain values that are smaller then 3.

c = [[2],[0,1]] because the [2] nd element of the first sublist in b is below 3 and [0,1] because the first and second element in the second sublist in b is below 3.

I tried :

for i in a:

   for o in i:

      if o < 3:

         print(i)

It only returns the original matrix.

How do I get b&c in python?

edited Jan 1 at 16:14

Patrick Artner

25.3k62444

asked Jan 1 at 15:47

wayne64001

475

1

"Matrix b is that a[0], a[1] have a value that is smaller than 3, c is a[0][2] and a[0][0], a[0][1] is less than 3". This doesn't make the question sound clear at all

– Bazingaa
Jan 1 at 16:04

This doesn't give it in the exact form you are looking for, but depending on why you want to do this, you might be interested in np.where(a<3) which outputs the tuple ([0,1,1],[2,0,1]) giving all the indices where a<3.

– tch
Jan 1 at 17:00

add a comment |

-2

Assume that I have a matrix:

a = [[4,7,2],[0,1,4],[4,5,6]]

And I want to get

b = [0, 1]

c = [[2],[0,1]]

b = [0,1] because the inner lists of a at position 0 and 1 contain values that are smaller then 3.

c = [[2],[0,1]] because the [2] nd element of the first sublist in b is below 3 and [0,1] because the first and second element in the second sublist in b is below 3.

I tried :

for i in a:

   for o in i:

      if o < 3:

         print(i)

It only returns the original matrix.

How do I get b&c in python?

edited Jan 1 at 16:14

Patrick Artner

25.3k62444

asked Jan 1 at 15:47

wayne64001

475

1

"Matrix b is that a[0], a[1] have a value that is smaller than 3, c is a[0][2] and a[0][0], a[0][1] is less than 3". This doesn't make the question sound clear at all

– Bazingaa
Jan 1 at 16:04

This doesn't give it in the exact form you are looking for, but depending on why you want to do this, you might be interested in np.where(a<3) which outputs the tuple ([0,1,1],[2,0,1]) giving all the indices where a<3.

– tch
Jan 1 at 17:00

add a comment |

-2

Assume that I have a matrix:

a = [[4,7,2],[0,1,4],[4,5,6]]

And I want to get

b = [0, 1]

c = [[2],[0,1]]

b = [0,1] because the inner lists of a at position 0 and 1 contain values that are smaller then 3.

c = [[2],[0,1]] because the [2] nd element of the first sublist in b is below 3 and [0,1] because the first and second element in the second sublist in b is below 3.

I tried :

for i in a:

   for o in i:

      if o < 3:

         print(i)

It only returns the original matrix.

How do I get b&c in python?

edited Jan 1 at 16:14

Patrick Artner

25.3k62444

asked Jan 1 at 15:47

wayne64001

475

Assume that I have a matrix:

a = [[4,7,2],[0,1,4],[4,5,6]]

And I want to get

b = [0, 1]

c = [[2],[0,1]]

b = [0,1] because the inner lists of a at position 0 and 1 contain values that are smaller then 3.

c = [[2],[0,1]] because the [2] nd element of the first sublist in b is below 3 and [0,1] because the first and second element in the second sublist in b is below 3.

I tried :

for i in a:

   for o in i:

      if o < 3:

         print(i)

It only returns the original matrix.

How do I get b&c in python?

python python-3.x numpy for-loop enumerate

edited Jan 1 at 16:14

Patrick Artner

25.3k62444

asked Jan 1 at 15:47

wayne64001

475

edited Jan 1 at 16:14

Patrick Artner

25.3k62444

asked Jan 1 at 15:47

wayne64001

475

edited Jan 1 at 16:14

Patrick Artner

25.3k62444

edited Jan 1 at 16:14

Patrick Artner

25.3k62444

edited Jan 1 at 16:14

Patrick Artner

25.3k62444

asked Jan 1 at 15:47

wayne64001

475

asked Jan 1 at 15:47

wayne64001

475

asked Jan 1 at 15:47

wayne64001

475

1

"Matrix b is that a[0], a[1] have a value that is smaller than 3, c is a[0][2] and a[0][0], a[0][1] is less than 3". This doesn't make the question sound clear at all

– Bazingaa
Jan 1 at 16:04

This doesn't give it in the exact form you are looking for, but depending on why you want to do this, you might be interested in np.where(a<3) which outputs the tuple ([0,1,1],[2,0,1]) giving all the indices where a<3.

– tch
Jan 1 at 17:00

add a comment |

1

"Matrix b is that a[0], a[1] have a value that is smaller than 3, c is a[0][2] and a[0][0], a[0][1] is less than 3". This doesn't make the question sound clear at all

– Bazingaa
Jan 1 at 16:04

This doesn't give it in the exact form you are looking for, but depending on why you want to do this, you might be interested in np.where(a<3) which outputs the tuple ([0,1,1],[2,0,1]) giving all the indices where a<3.

– tch
Jan 1 at 17:00

"Matrix b is that a[0], a[1] have a value that is smaller than 3, c is a[0][2] and a[0][0], a[0][1] is less than 3". This doesn't make the question sound clear at all

– Bazingaa
Jan 1 at 16:04

This doesn't give it in the exact form you are looking for, but depending on why you want to do this, you might be interested in np.where(a<3) which outputs the tuple ([0,1,1],[2,0,1]) giving all the indices where a<3.

– tch
Jan 1 at 17:00

add a comment |

1 Answer
1

active

oldest

votes

You can leverate enumerate(iterable[,startingvalue]) which gives you the index and the value of the thing you iterate over:

a = [[4,7,2],[0,1,4],[4,5,6]] 



thresh = 3

b =  # collects indexes of inner lists with values smaller then thresh

c =  # collects indexes in the inner lists that are smaller then thresh

for idx, inner_list in enumerate(a):

    if any(value < thresh for value in inner_list):

        b.append(idx)

        c.append()

        for idx_2, value in enumerate(inner_list):

            if value < thresh:

                c[-1].append(idx_2)



print(a)

print(b)

print(c)

Output:

[[4, 7, 2], [0, 1, 4], [4, 5, 6]]

[0, 1]

[[2], [0, 1]]

Doku:

enumerate()

any()

answered Jan 1 at 15:56

Patrick Artner

25.3k62444

add a comment |

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1 Answer
1

active

oldest

votes

1 Answer
1

active

oldest

votes

You can leverate enumerate(iterable[,startingvalue]) which gives you the index and the value of the thing you iterate over:

a = [[4,7,2],[0,1,4],[4,5,6]] 



thresh = 3

b =  # collects indexes of inner lists with values smaller then thresh

c =  # collects indexes in the inner lists that are smaller then thresh

for idx, inner_list in enumerate(a):

    if any(value < thresh for value in inner_list):

        b.append(idx)

        c.append()

        for idx_2, value in enumerate(inner_list):

            if value < thresh:

                c[-1].append(idx_2)



print(a)

print(b)

print(c)

Output:

[[4, 7, 2], [0, 1, 4], [4, 5, 6]]

[0, 1]

[[2], [0, 1]]

Doku:

enumerate()

any()

answered Jan 1 at 15:56

Patrick Artner

25.3k62444

add a comment |

You can leverate enumerate(iterable[,startingvalue]) which gives you the index and the value of the thing you iterate over:

a = [[4,7,2],[0,1,4],[4,5,6]] 



thresh = 3

b =  # collects indexes of inner lists with values smaller then thresh

c =  # collects indexes in the inner lists that are smaller then thresh

for idx, inner_list in enumerate(a):

    if any(value < thresh for value in inner_list):

        b.append(idx)

        c.append()

        for idx_2, value in enumerate(inner_list):

            if value < thresh:

                c[-1].append(idx_2)



print(a)

print(b)

print(c)

Output:

[[4, 7, 2], [0, 1, 4], [4, 5, 6]]

[0, 1]

[[2], [0, 1]]

Doku:

enumerate()

any()

answered Jan 1 at 15:56

Patrick Artner

25.3k62444

add a comment |

You can leverate enumerate(iterable[,startingvalue]) which gives you the index and the value of the thing you iterate over:

a = [[4,7,2],[0,1,4],[4,5,6]] 



thresh = 3

b =  # collects indexes of inner lists with values smaller then thresh

c =  # collects indexes in the inner lists that are smaller then thresh

for idx, inner_list in enumerate(a):

    if any(value < thresh for value in inner_list):

        b.append(idx)

        c.append()

        for idx_2, value in enumerate(inner_list):

            if value < thresh:

                c[-1].append(idx_2)



print(a)

print(b)

print(c)

Output:

[[4, 7, 2], [0, 1, 4], [4, 5, 6]]

[0, 1]

[[2], [0, 1]]

Doku:

enumerate()

any()

answered Jan 1 at 15:56

Patrick Artner

25.3k62444

You can leverate enumerate(iterable[,startingvalue]) which gives you the index and the value of the thing you iterate over:

a = [[4,7,2],[0,1,4],[4,5,6]] 



thresh = 3

b =  # collects indexes of inner lists with values smaller then thresh

c =  # collects indexes in the inner lists that are smaller then thresh

for idx, inner_list in enumerate(a):

    if any(value < thresh for value in inner_list):

        b.append(idx)

        c.append()

        for idx_2, value in enumerate(inner_list):

            if value < thresh:

                c[-1].append(idx_2)



print(a)

print(b)

print(c)

Output:

[[4, 7, 2], [0, 1, 4], [4, 5, 6]]

[0, 1]

[[2], [0, 1]]

Doku:

enumerate()

any()

answered Jan 1 at 15:56

Patrick Artner

25.3k62444

answered Jan 1 at 15:56

Patrick Artner

25.3k62444

answered Jan 1 at 15:56

Patrick Artner

25.3k62444

answered Jan 1 at 15:56

Patrick Artner

25.3k62444

add a comment |

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