Convert a 1D array to a 2D array in numpy

Question

I want to convert a 1-dimensional array into a 2-dimensional array by specifying the number of columns in the 2D array  Something that would work like this    gt  import numpy as np  gt  A   np array  1 2 3 4 5 6    gt  B   vec2matrix A ncol 2   gt  B array   1  2           3  4           5  6      Does numpy have a function that works like my made-up function  vec2matrix    I understand that you can index a 1D array like a 2D array  but that isn t an option in the code I have - I need to make this conversion

User · Answer

If your sole purpose is to convert a 1d array X to a 2d array just do   X   np reshape X  1  X size

User · Answer

Try something like   B   np reshape A  -1 ncols     You ll need to make sure that you can divide the number of elements in your array by ncols though  You can also play with the order in which the numbers are pulled into B using the order keyword

User · Answer

import numpy as np array   np arange 8   print  Original array    n   array  array   np arange 8  reshape 2  4  print  New array    n   array

User · Answer

Change 1D array into 2D array without using Numpy   l    i for i in range 1 21   part   3 new      start  end   0  part   while end  lt   len l       temp          for i in range start  end           temp append l i       new append temp      start    part     end    part print  new values      new      for uneven cases temp      while start  lt  len l       temp append l start       start    1     new append temp  print  new values for uneven cases       new

User · Answer

There is a simple way as well  we can use the reshape function in a different way  A reshape   A reshape No of rows  No of columns

User · Answer

You have two options    If you no longer want the original shape  the easiest is just to assign a new shape to the array  a shape    a size  ncols  ncols    You can switch the a size  ncols by -1 to compute the proper shape automatically  Make sure that a shape 0  a shape 1  a size  else you ll run into some problem  You can get a new array with the np reshape function  that works mostly like the version presented above  new   np reshape a   -1  ncols     When it s possible  new will be just a view of the initial array a  meaning that the data are shared  In some cases  though  new array will be acopy instead  Note that np reshape also accepts an optional keyword order that lets you switch from row-major C order to column-major Fortran order  np reshape is the function version of the a reshape method    If you can t respect the requirement a shape 0  a shape 1  a size  you re stuck with having to create a new array  You can use the np resize function and mixing it with np reshape  such as   gt  gt  gt  a  np arange 9   gt  gt  gt  np resize a  10  reshape 5 2

User · Answer

some array shape    1   some array shape   or get a new one  another array   numpy reshape some array   1   some array shape    This will make dimensions  1  equals to adding a bracket on the outermost

User · Answer

convert a 1-dimensional array into a 2-dimensional array by adding new axis  a np array  10 20 30 40 50 60    b a   np newaxis --it will convert it to two dimension

User · Answer

You want to reshape the array   B   np reshape A   -1  2     where -1 infers the size of the new dimension from the size of the input array

User · Answer

You can useflatten   from the numpy package   import numpy as np a   np array   1  2           3  4           5  6    a flat   a flatten   print f original array   a   nflattened array    a flat      Output   original array    1 2    3 4    5 6    flattened array    1 2 3 4 5 6

[python] Convert a 1D array to a 2D array in numpy

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