tf.keras.backend.placeholder
  
  Instantiates a placeholder tensor and returns it.
  
  tf.keras.backend.placeholder(
    shape=None, ndim=None, dtype=None, sparse=False, name=None, ragged=False
)
  
   
    
     
     
    
    
     
      | Arguments | 
     
     
      shape | 
      Shape of the placeholder (integer tuple, may include None entries). | 
     
     
      ndim | 
      Number of axes of the tensor. At least one of {shape, ndim} must be specified. If both are specified, shape is used. | 
     
     
      dtype | 
      Placeholder type. | 
     
     
      sparse | 
      Boolean, whether the placeholder should have a sparse type. | 
     
     
      name | 
      Optional name string for the placeholder. | 
     
     
      ragged | 
      Boolean, whether the placeholder should have a ragged type. In this case, values of 'None' in the 'shape' argument represent ragged dimensions. For more information about RaggedTensors, see this guide. | 
     
    
   
   
  
   
    
     
     
    
    
     
      | Raises | 
     
     
      ValueError | 
      If called with eager execution | 
     
     
      ValueError | 
      If called with sparse = True and ragged = True. | 
     
    
   
   
  
   
    
     
     
    
    
     
      | Returns | 
     
     
      | Tensor instance (with Keras metadata included). | 
     
    
   
   
  Examples:
  input_ph = tf.keras.backend.placeholder(shape=(2, 4, 5))
input_ph
<tf.Tensor 'Placeholder_...' shape=(2, 4, 5) dtype=float32>