An array shows 3 numbers randomly, and I had to write a code that sums the 3 numbers, but the array has a trick to sometimes show a string:
[96, ".!asd", 182]
["@#$%", 5, 43]
[64, "bd", 48]
I would like to use an "if" that would return "not valid" if there's a string in the array.
if (...){
return not valid
}
Please, if there's a way to identify any string, could you tell me the code?
You can use Array.prototype.some() to see if your array contains NaN's
var x = [96, ".!asd", 182]
var y = [96, 1000, 182]
console.log(x.some(isNaN))
console.log(y.some(isNaN))
You can use isNaN to determine if a stirng is a number
isNaN('123') //false
isNaN('Hello') //true
Use the object Number:
if (Number.isNaN(+element_in_array)) return "Not Valid!!"
function sum(array) {
if (array.some((n) => Number.isNaN(+n))) {
return "Invalid data, at least one element is not a number.";
}
return array.reduce((a, n) => a + Number(n), 0);
}
console.log(sum([96, ".!asd", 182]))
console.log(sum(["@#$%", 5, 43]))
console.log(sum([64, "bd", 48]))
console.log(sum([64, 44, 48]))
You should use the isNaN function as it is explained here : Is there a (built-in) way in JavaScript to check if a string is a valid number?
isNaN(123) // false
isNaN('123') // false
isNaN('1e10000') // false (This translates to Infinity, which is a number)
isNaN('foo') // true
isNaN('10px') // true
You could use NaN to determine if all elements are numbers by using an unary plus to convert the string to number. If succeed, you get a number for summing, if not then NaN is returned and summed. A single NaN spoils the result and the result is NaN.
function not(fn) {
return function (v) {
return !fn(v);
};
}
function sum(array) {
return array.reduce((a, b) => +a + +b);
}
console.log([[96, ".!asd", 182], ["@#$%", 5, 43], [64, "bd", 48], [2, 3, 5]].map(sum).filter(not(isNaN)));
try using typeof to validate wether or not you are dealing with a string.mdn typeof
You can use if type(x) == str to check if a variable x is of type String. It is a built-in function. Please refer to official python documentation to know more.
