How can I count number of letter "a" into every element of the array?
let a = ['Guatemala', 'Canada', 'Costa Rica', 'Anguilla', 'North Korea'];
I try to use split() method, but could not finish ....
let a = ['Guatemala', 'Canada', 'Costa Rica', 'Anguilla', 'North Korea'];
let newA = a.toString();
for(i = 0; i < a.length; i++) {
let newAr = a[i].split(',');
for(j = 0; j < newAr.length; j++) {
console.log(newAr[j].split(','));
}
}
Thank you!
The
map()method creates a new array with the results of calling a provided function on every element in the calling array.
The
match()method retrieves the matches when matching a string against a regular expression.
You can use map() and match() to get the array of count in each string item:
let a = ['Guatemala', 'Canada', 'Costa Rica', 'Anguilla', 'North Korea'];
let aCountArr = a.map(i => {
return i.match(/a/g).length;
});
console.log(aCountArr);OR: You can use for...of
The for...of statement creates a loop iterating over iterable objects, including: built-in String, Array, Array-like objects (e.g., arguments or NodeList), TypedArray, Map, Set, and user-defined iterables. It invokes a custom iteration hook with statements to be executed for the value of each distinct property of the object.
let a = ['Guatemala', 'Canada', 'Costa Rica', 'Anguilla', 'North Korea'];
let aCountArr = [];
for(let c of a){
aCountArr.push(c.match(/a/g).length)
}
console.log(aCountArr);How can I count number of letter "a" into every element of the array?
If the goal is to end up with a new array with the counts of how many as there are in the word in the first array, then map and reduce should do it:
let a = ['Guatemala', 'Canada', 'Costa Rica', 'Anguilla', 'North Korea'];
let result = a.map(entry =>
Array.from(entry).reduce((counter, ch) =>
ch === "a" ? counter + 1 : counter,
0
)
);
console.log(result);map loops through the original array letting us process each entry and produce a result for it. We turn the string into an array of characters, then use reduce to count how many of those are as.
There are about eighteen other ways. :-) For instance, we could use replace to remove all characters that aren't a and take the length:
let a = ['Guatemala', 'Canada', 'Costa Rica', 'Anguilla', 'North Korea'];
let result = a.map(entry =>
entry.replace(/[^a]/g, "").length
);
console.log(result);
map and reduce/replace) could be replaced with for loops.for loops.Get count for every element in array:
let a = ['Guatemala', 'Canada', 'Costa Rica', 'Anguilla', 'North Korea'];
let count = a.map(el => el.match(/a/g).length);
console.log(count);Get count for entire array as whole:
let a = ['Guatemala', 'Canada', 'Costa Rica', 'Anguilla', 'North Korea'];
let count = a.join('').match(/a/g).length;
console.log(count);