value error #28

File "C:\Users\Bilva Prasad\Anaconda3\lib\site-packages\sklearn\utils\validation.py", line 521, in check_array
"if it contains a single sample.".format(array))
ValueError: Expected 2D array, got 1D array instead:
array=[].
Reshape your data either using array.reshape(-1, 1) if your data has a single feature or array.reshape(1, -1) if it contains a single sample.

how to fix this??