code: def row(df, col_name, tf_name=None):
      """
      Automatically infers a placeholder from a dataframe. The shape returned is that of one row of
      data in the dataframe.
  
      The placeholder uses implicitly the current computation graph of tensorflow.
  
      :param df: a Spark dataframe
      :param col_name: the name of a column in a dataframe
      :param tf_name: if specified, the name assigned to the placeholder. If not specified,
      it will be the name of the column.
      :return: a TensorFlow placeholder.
      """
      return _auto_placeholder(df, col_name, tf_name, block=False)
  
imports: import tensorflow
  import numpy
  import logging
  import tempfile
  import pandas
  from pyspark import RDD, SparkContext
  from pyspark.sql import SQLContext, Row, DataFrame
  from pyspark.sql.types import DoubleType, IntegerType, LongType, FloatType, ArrayType
label_desc: Use image node_id 23 for calling a global function with example usage: row(df, col_name, tf_name) and returns: _auto_placeholder