title: Scala Apache Spark: Nonstandard characters in column names
body: <p>I'm calling the following:</p>
  
  <pre><code>  propertiesDF.select(
          col("timestamp"), col("coordinates")(0) as "lon", 
          col("coordinates")(1) as "lat", 
          col("properties.tide (above mllw)") as "tideAboveMllw",
          col("properties.wind speed") as "windSpeed")
  </code></pre>
  
  <p>This gives me the following error:</p>
  
  <blockquote>
    <p>org.apache.spark.sql.AnalysisException: No such struct field tide
    (above mllw) in air temperature, atmospheric pressure, dew point,
    dominant wave period, mean wave direction, name, program name,
    significant wave height, tide (above mllw):, visibility, water
    temperature, wind direction, wind speed;</p>
  </blockquote>
  
  <p>Now there definitely is such a struct field.  (The error message itself says so.)</p>
  
  <p>Here is the schema:</p>
  
  <pre><code> root
   |-- timestamp: long (nullable = true)
   |-- coordinates: array (nullable = true)
   |    |-- element: double (containsNull = true)
   |-- properties: struct (nullable = true)
   |    |-- air temperature: double (nullable = true)
   |    |-- atmospheric pressure: double (nullable = true)
   |    |-- dew point: double (nullable = true)
            .
            .
            .
   |    |-- tide (above mllw):: string (nullable = true)
            .
            .
            .
  </code></pre>
  
  <p>The input is read as JSON like this: </p>
  
  <pre><code>val df = sqlContext.read.json(dirName)
  </code></pre>
  
  <p>How do I handle parentheses in a column name?</p>