How do i take radio value checked in vuejs? - vue.js

Question

I have this code so far, i try to take the value from radio button.I can take from v-model value but with radio i have some problems.For example if i have more radio buttons how i can take the checked one.
new Vue({
el:'#root',
data:{
removelines: [
{value:'a'},
{value:'b'}
]
},
methods:{
insert:function(){
let vueIn = this;
axios.post('/vue', {removelines: vueIn.removelines.value}).then(
function(response){
vueIn.removelines = response.data.removelines.value;
}
).catch(function(error){ console.log(error.message); });
}
}
});
html code here:
<div class="card-block">
<div class="btn-group" data-toggle="buttons">
<label class="btn btn-warning active">
<input v-model="removelines" name="removelines" type="radio" class ="cheker" autocomplete="off" v-bind:value="a" checked>
Yes
</label>
<label class="btn btn-warning">
<input v-model="removelines" name="removelines" type="radio" class ="cheker" v-bind:value="b">
No
</label>
</div>
</div>

Answer 1

Check this working sample, please.
new Vue({
el: '#root',
data: {
removelines: 'b'
}
});
<script src="https://unpkg.com/vue#2.4.2/dist/vue.js"></script>
<div id="root">
<div class="card-block">
{{ removelines }}
<div class="btn-group" data-toggle="buttons">
<label class="btn btn-warning active">
<input v-model="removelines" name="removelines" type="radio" class ="cheker" autocomplete="off" v-bind:value="'a'" checked>
Yes
</label>
<label class="btn btn-warning">
<input v-model="removelines" name="removelines" type="radio" class ="cheker" v-bind:value="'b'">
No
</label>
</div>
</div>
</div>