I'm trying to remove part of the value of an element in an array after '_' and once its done remove all repeated elements.
Array looks like
names = ["ann_w", "james_q", "ann_q", "peter_p", "steve_q", "james_s"];
And I am trying to convert it into
names = ["ann", "james", "peter", "steve"];
Below code is returning undefined and cant figure it out how to remove all repeated elements.
for (i = 0; i < names.length; i++) {
names[i] = names[i].substring(names[i].indexOf("_") + 1);
}
use Set & map:
var names = ["ann_w", "james_q", "ann_q", "peter_p", "steve_q", "james_s"];
var unique_names = [ ...new Set(names.map(name => {
return name.split('_')[0]
}))]
console.log(unique_names)
var unique_names = [ ...new Set(names.map(name => name.split('_')[0]))];
var names = ["ann_w", "james_q", "ann_q", "peter_p", "steve_q", "james_s"];
var tmp = names.map(function(n){
return n.split("_")[0];
}).sort();
// tmp = ["ann", "ann", "james", "james", "peter", "steve"]
var result = [];
tmp.forEach(function(t){
if(!result.includes(t))
result.push(t);
});
console.log(result);
You can try using split on the string instead of doing the substring, then you'd get an array of strings, and since you only want the first name, you'd take array[0].
Also, you're getting back errors because you're trying to substring the entire array instead of a string. You'd need to do names[i] = names[i].substring
You can do this: Use array#reduce and Object.keys.
reduce will create an object with name as keys and then you can get the key as an array via Object.keys().
var names = ["ann_w", "james_q", "ann_q", "peter_p", "steve_q", "james_s"];
var obj = names.reduce(function(r,v) {
var name = v.split('_')[0];
if(!r[name]) {
r[name] = 1;
}
return r;
}, {});
console.log(Object.keys(obj));
var names = ["ann_w", "james_q", "ann_q", "peter_p", "steve_q", "james_s"];
var finalArray = [];
for (var i = 0; i <names.length; i++){
var substringArray = names[i].split("_");
if(finalArray.indexOf(substringArray[0]) == -1) finalArray.push(substringArray[0]);
}
names = ["ann_w", "james_q", "ann_q", "peter_p", "steve_q", "james_s"];
for (i = 0; i < names.length; i++) {
names[i] = names[i].substring(0, names[i].indexOf("_"));
}
var unique = names.filter(function(item, i, names) {
return i == names.indexOf(item);
});
console.log(unique)
