converting array to a true/false matrices
You can try this one line solution:
d = pd.json_normalize([{
    &quot;label&quot;:&quot;bad&quot;,
    &quot;id&quot;: &quot;0009&quot;,
    &quot;signals&quot;:[&quot;high_debt_ratio&quot;, &quot;no_job&quot;] 
},

{
    &quot;label&quot;:&quot;good&quot;,
     &quot;id&quot;: &quot;0002&quot;,
    &quot;signals&quot;:[&quot;high_debt_ratio&quot;, &quot;great_credit&quot;, &quot;no_id_match&quot;] 
},

{
    &quot;label&quot;:&quot;good&quot;,
    &quot;id&quot;: &quot;0003&quot;,
    &quot;signals&quot;:[&quot;low_debt_ratio&quot;, &quot;great_credit&quot;] 
},

{
    &quot;label&quot;:&quot;bad&quot;,
    &quot;id&quot;: &quot;0001&quot;,
    &quot;signals&quot;:[&quot;high_risk_loc&quot;, &quot;high_debt_ratio&quot;, &quot;no_job&quot;, &quot;no_id_match&quot;] 
}])

d.merge(d.signals.apply(lambda x: &quot;|&quot;.join(x)).str.get_dummies(sep = &quot;|&quot;), left_index = True, right_index= True)

Outputs: