Can I insert angular data into an HTML attribute? [duplicate]

I'm trying to use *ngFor to generate a table that is collapsible. Doing this though requires a unique id matching both the tr element with the data-target attribute for the collapsible to work. My plan is to use the User's ID from the backend as this unique identifier. I can't seem to find the correct syntax for this.

Below is the code I've tried, but I know this isn't the correct syntax. the "data-target" attribute is what I need the help with.

<table class="table table-condensed table-striped">
          <thead>
            <tr>
              <th></th>
              <th>Fist Name</th>
              <th>Last Name</th>
            </tr>
          </thead>

          <tbody>
            <tr
              data-toggle="collapse"
              data-target="#demo[[user.id]]"
              class="accordion-toggle"
              *ngFor="let user of viewUsers"
            >
              <td>
                <button class="btn btn-default btn-xs">
                  <span class="glyphicon glyphicon-eye-open"></span>
                </button>
              </td>
              <td>{{ user.firstName }}</td>
              <td>{{ user.lastName }}</td>
            </tr>

            <tr>
              <td colspan="12" class="hiddenRow">
                <div class="accordian-body collapse" id="demo[[user.id]]">
                  <table class="table table-striped">
                    <thead>
                      <tr class="info">
                        <th>Job</th>
                        <th>Company</th>
                        <th>Salary</th>
                        <th>Date On</th>
                        <th>Date off</th>
                        <th>Action</th>
                      </tr>
                    </thead>