Returns a column which is the input column scaled to have range [0,1].

x A numeric Tensor.
key A Tensor of type string.
elementwise If true, scale each element of the tensor independently.
key_vocabulary_filename (Optional) The file name for the per-key file. If None, this combiner will assume the keys fit in memory and will not store the analyzer result in a file. If '', a file name will be chosen based on the current TensorFlow scope. If not '', it should be unique within a given preprocessing function.
name (Optional) A name for this operation.

A Tensor containing the input column scaled to [0, 1], per key. If the analysis dataset is empty or contains a single distinct value, then x is scaled using a sigmoid function.