Lightning Select component markup with select inside iteration.

gistfile1.txt

<aura:attribute name="selectOptions" type="object[]" description="A list of objects with value (ID) and text (label) attributes"/>
<aura:attribute name="selectedOption" type="ID" default="" description="The value of the selected option"/>
    
<lightning:select name="selectName" label="My Select" value="{!v.selectedOption}" onchange="{!c.doSomething}" required="true">
    <aura:iteration items="{!v.selectOptions}" var="option">
        <option value="{!option.value}" selected="{!if(v.selectedOption==option.value,'selected','')}">{!option.text}</option>
    </aura:iteration>
</lightning:select>