title: How to use a variable with space in Kotlin data class
body: <p><strong>Context</strong>:
  I am passing the x value, y value and z value from an <strong>Arduino accelerometer sensor</strong> to <strong>Firebase Realtime Database</strong>. The way Arduino passes the values to real-time database is shown below (X Axis, Y Axis, Z Axis). I could not change the way it passes the variable name to Firebase. I want it to be like <em><strong>x_axis</strong></em>, <em><strong>y_axis</strong></em>, and so on.</p>
  <pre><code>***FIREBASE REALTIME DATABASE
  
  &quot;data&quot;: {
          &quot;data1&quot;: {
            &quot;X Axis&quot;: 0.78,
            &quot;Y Axis&quot;: 0.91,
            &quot;Z Axis&quot;: 0.07
          },
          &quot;data2&quot;: {
            &quot;X Axis&quot;: 0.23,
            &quot;Y Axis&quot;: 0.21,
            &quot;Z Axis&quot;: 0.43
          }
        }
  </code></pre>
  <p>My Kotlin data class to accommodate this is shown below (<em><strong>using backtick to define the variable and identifier suppress at top of the file + turned off the Identifier linting in IDE setting</strong></em>):</p>
  <pre><code>@file:Suppress(&quot;IllegalIdentifier&quot;)
  package com.example.projectxyz.model.user_list
  
  data class DataMeasured(
      val `X Axis`: Double = 0.00,
      val `Y Axis`: Double = 0.00,
      val `Z Axis`: Double = 0.00,
  )
  </code></pre>
  <p>This is the error I am getting when tried to build the app:</p>
  <pre><code>&gt; Task :app:dexBuilderDebug FAILED
  AGPBI: {&quot;kind&quot;:&quot;error&quot;,&quot;text&quot;:&quot;com.android.tools.r8.internal.XI0: Space characters in SimpleName 'X Axis' are not allowed prior to DEX version 040&quot;,&quot;sources&quot;:[{&quot;file&quot;:&quot;C:\\01PrasanthCodes\\ProjectsPras\\1AndroidDevelopment\\Harinivas\\app\\build\\tmp\\kotlin-classes\\debug\\com\\example\\projectxyz\\model\\user_list\\DataMeasured.class&quot;}],&quot;tool&quot;:&quot;D8&quot;}
  AGPBI: {&quot;kind&quot;:&quot;error&quot;,&quot;text&quot;:&quot;com.android.tools.r8.internal.XI0: Space characters in SimpleName 'X Axis' are not allowed prior to DEX version 040&quot;,&quot;sources&quot;:[{&quot;file&quot;:&quot;C:\\01PrasanthCodes\\ProjectsPras\\1AndroidDevelopment\\Harinivas\\app\\build\\tmp\\kotlin-classes\\debug\\com\\example\\projectxyz\\model\\user_list\\DataMeasured.class&quot;}],&quot;tool&quot;:&quot;D8&quot;}
  </code></pre>
  <p>Is there any way for me to overcome this issue? Thank you so much</p>