Error in Python script Expected 2D array got 1D array instead

Question

I m following this tutorial to make this ML prediction   import numpy as np import matplotlib pyplot as plt from matplotlib import style  style use  ggplot   from sklearn import svm  x    1  5  1 5  8  1  9  y    2  8  1 8  8  0 6  11   plt scatter x y  plt show    X   np array   1 2                 5 8                 1 5 1 8                 8 8                 1 0 6                 9 11     y    0 1 0 1 0 1  X reshape 1  -1   clf   svm SVC kernel  linear   C   1 0  clf fit X y   print clf predict  0 58 0 76      I m using Python 3 6 and I get error  Expected 2D array  got 1D array instead   I think the script is for older versions  but I don t know how to convert it to the 3 6 version   Already try with the   X reshape 1  -1

User · Answer

Just insert the argument between a double square bracket  regressor predict   values     that worked for me

User · Answer

You are just supposed to provide the predict method with the same 2D array  but with one value that you want to process  or more   In short  you can just replace   0 58 0 76    With    0 58 0 76     And it should work   EDIT  This answer became popular so I thought I d add a little more explanation about ML  The short version  we can only use predict on data that is of the same dimensionality as the training data  X  was    In the example in question  we give the computer a bunch of rows in X  with 2 values each  and we show it the correct responses in y  When we want to predict using new values  our program expects the same - a bunch of rows  Even if we want to do it to just one row  with two values   that row has to be part of another array

User · Answer

I faced the same problem  You just have to make it an array and moreover you have to put double squared brackets to make it a single element of the 2D array as first bracket initializes the array and the second makes it an element of that array    So simply replace the last statement by   print clf predict np array  0 58 0 76

User · Answer

I use the below approach   reg   linear model LinearRegression   reg fit df   year    df income   reg predict   2136

User · Answer

With one feature my Dataframe list converts to a Series  I had to convert it back to a Dataframe list and it worked   if type X  is Series      X   X to frame

User · Answer

I faced the same issue except that the data type of the instance I wanted to predict was a panda Series object   Well I just needed to predict one input instance  I took it from a slice of my data   df   pd DataFrame list BiogasPlant objects all     test   df iloc -1           sliced it here   In this case  you ll need to convert it into a 1-D array  and then reshape it    test2d   test values reshape 1 -1    From the docs  values will convert Series into a numpy array

User · Answer

I was facing the same issue earlier but I have somehow found the solution  You can try reg predict   3300        The API used to allow scalar value but now you need to give a 2D array

User · Answer

The X and Y matrix of Independent Variable and Dependent Variable respectively to DataFrame from int64 Type so that it gets converted from 1D array to 2D array    i e X pd DataFrame X  and Y pd dataFrame Y  where pd is of pandas class in python  and thus feature scaling in-turn doesn t lead to any error

User · Answer

The problem is occurring when you run prediction on the array  0 58 0 76   Fix the problem by reshaping it before you call predict     import numpy as np import matplotlib pyplot as plt from matplotlib import style  style use  ggplot   from sklearn import svm  x    1  5  1 5  8  1  9  y    2  8  1 8  8  0 6  11   plt scatter x y  plt show    X   np array   1 2                 5 8                 1 5 1 8                 8 8                 1 0 6                 9 11     y    0 1 0 1 0 1   clf   svm SVC kernel  linear   C   1 0  clf fit X y   test   np array  0 58  0 76   print test         Produces    0 58  0 76  print test shape   Produces   2   meaning 2 rows  1 col  test   test reshape 1  -1  print test         Produces     0 58  0 76   print test shape   Produces  1  2  meaning 1 row  2 cols  print clf predict test     Produces  0   as expected

[python] Error in Python script "Expected 2D array, got 1D array instead:"?

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