Pass Lightning input iteration value by index of String array

Question

I have a lightning component where I dynamically generate some columns and some input fields. I have a String Array as attribute. How do I get the index of the array to pass the value. I tried below but this gives me an expression error.

Attribute

<aura:attribute name="searchKeywordArr" type="String[]" description="store search input"/>

Iteration

 <aura:iteration items="{!v.colData}" var="obj" indexVar="index">
                            <td role="gridcell">
                                <lightning:input 
                                                 value="{!v.searchKeywordArr[v.indexVar]}"
                                                 required="false"
                                                 placeholder="{!obj.label + '...'}"
                                                 aura:id="{!obj.Id}"
                                                 label="{!obj.label}"
                                                 variant="label-hidden"/>
                                
                            </td>
                        </aura:iteration>

Answer 1

For anyone looking for an anwer. The following works

Component:

  <aura:iteration items="{!v.colData}" var="obj" indexVar="index">
        <lightning:input type="text" name="{!index}" value="{!obj}" label="Lightning Input" onchange="{!c.update}"/>
     </aura:iteration>

Javascriptcontroller:

update : function(component,event){
        var index = event.getSource().get('v.name');
            alert('index' + index);  
        var value = event.getSource().get('v.value');
              alert('value' + value);  
    }