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javascriptangularjstimeecmascript-5

Transform 12h clock values to 24h clock values

Given a number of strings that contain clock values such as "12.00 am - 4.00 pm", "4.00 - 9.00 am" and "5.00 am - 9.00 am, 1.00 - 8.00 pm", how can I transform each of them into their 24h equivalent, in this case "12:00-16:00", "4.00-9.00" and "5.00-9.00, 13.00-20.00"?

Solution 
  • var str = "12.00 am - 4.00 pm\n4.00 - 9.00 am\n5.00 am - 9.00 am\n1.00 - 8.00 pm";
var reg = /(\d+\.\d+)( am| pm|)? - (\d+\.\d+) (am|pm)/g;
str.replace(reg,function myfun(g,g1,g2,g3,g4){
    if(!g2){
        g2 = g4
    }
    if(g2=='pm'){
        g1 = (parseInt(g1)+12)+".00";
    }
    if(g4=='pm'){
        g3 = (parseInt(g3)+12)+".00";
    }
    return g1+" - "+g3;
});

    I tried it with javascript and regex. 

    Result:
    12.00 - 16.00
    4.00 - 9.00
    5.00 - 9.00
    13.00 - 20.00