class_docstr: Class implementing ArrayFeatureExtractor in PyTorch
  
  This is used by SelectKBest, VarianceThreshold operators in scikit-learn
code: def forward(self, x):
      if isinstance(x, tuple):
          return x[self.column_indices]
      if len(x.shape) == 1:
          x = x.view(1, -1)
      if self.is_contiguous:
          return x[:, self.min : self.max]
      else:
          return torch.index_select(x, 1, self.column_indices)
  
imports: import torch
  from ._physical_operator import PhysicalOperator
label_desc: Use image node_id 2 for calling the ArrayFeatureExtractor obj's underlying member method code with example usage: obj.forward(x) and returns: x, x, torch