How to Uppercase Each Element of an Array

Convert array into upper case

you should use handler function in map:

var array2 = ["melon","banana","apple","orange","lemon"];
array2 = array2.map(function(x){ return x.toUpperCase(); })

for more information about map

edit: yes you can do

toUpper = function(x){ 
  return x.toUpperCase();
};
array2 = array2.map(toUpper);

How can I uppercase each element of an array?

Return a New Array

If you want to return an uppercased array, use #map:

array = ["Monday", "Tuesday", "Wednesday", "Thursday", "Friday"]

# Return the uppercased version.
array.map(&:upcase)
=> ["MONDAY", "TUESDAY", "WEDNESDAY", "THURSDAY", "FRIDAY"]

# Return the original, unmodified array.
array
=> ["Monday", "Tuesday", "Wednesday", "Thursday", "Friday"]

As you can see, the original array is not modified, but you can use the uppercased return value from #map anywhere you can use an expression.

Update Array in Place

If you want to uppercase the array in-place, use #map! instead:

array = ["Monday", "Tuesday", "Wednesday", "Thursday", "Friday"]
array.map!(&:upcase)
array
=> ["MONDAY", "TUESDAY", "WEDNESDAY", "THURSDAY", "FRIDAY"]

Capitalize first letter of each array element using JavaScript

You don't need to use .replace(). Use .charAt(0) to selecting first character of string and use .slice() to selecting next part of string

var beg2 = "first,second,third";var ans22 = "";var words = beg2.split(",");
for (var i=0; i<words.length; i++){  words[i] = words[i].charAt(0).toUpperCase() + words[i].slice(1);  ans22 += words[i] + "<br>"; }document.getElementById("ans22").innerHTML = ans22;

<div id="ans22"></div>

upperCase even characters and lowerCase odd characters in each element of an array in JavaScript

toUpperCase doesn't modify the string in place (JavaScript strings are immutable). You need to assign the result back to a variable.

function toWeirdCase(string) {  var reg = /\b(?![\s.])/  var res = string.split(reg)  var newArr = []
  for (let k = 0; k < res.length; k++) {    let newString = "";    for (let j = 0; j < res[k].length; j++) {      if (j % 2 == 0) {        newString += res[k].charAt(j).toUpperCase()      } else {        newString += res[k].charAt(j).toLowerCase()      }    }    newArr.push(newString)  }  return newArr.join('')}
console.log(toWeirdCase('This is a test'))

Formatting array elements into Uppercase and lower case format using JavaScript

You could use .map() with .replace() and the replacement method to convert your capital groups into lowercase groups like so:

const array1 = ["WORLDWIDE_AGRICULTURAL - CA"," WORLDWIDE_INDUSTRIAL - MX"];
const res = array1.map(str =>  str.replace(/(\w)(\w+)_(\w)(\w+)/g, (_, a, b, c, d) =>     `${a}${b.toLowerCase()} ${c}${d.toLowerCase()}`  ).trim());
console.log(res);

How can I capitalize all the strings inside an array directly?

update: Xcode 8.2.1 • Swift 3.0.2

var dogNames = ["Sean", "fido", "Sarah", "Parker", "Walt", "abby", "Yang"]

for (index, element) in dogNames.enumerated() {
    dogNames[index] = element.capitalized
}

print(dogNames)   // "["Sean", "Fido", "Sarah", "Parker", "Walt", "Abby", "Yang"]\n"

This is a typical case for using map():

let dogNames1 = ["Sean", "fido", "Sarah", "Parker", "Walt", "abby", "Yang"].map{$0.capitalized}

A filter() sample:

let dogNamesStartingWithS = ["Sean", "fido", "Sarah", "Parker", "Walt", "abby", "Yang"].filter{$0.hasPrefix("S")}

dogNamesStartingWithS   // ["Sean", "Sarah"]

you can combine both:

let namesStartingWithS = ["sean", "fido", "sarah", "parker", "walt", "abby", "yang"].map{$0.capitalized}.filter{$0.hasPrefix("S")}

namesStartingWithS   // ["Sean", "Sarah"]

You can also use the method sort (or sorted if you don't want to mutate the original array) to sort the result alphabetically if needed:

let sortedNames = ["sean", "fido", "sarah", "parker", "walt", "abby", "yang"].map{$0.capitalized}.sorted()

sortedNames  // ["Abby", "Fido", "Parker", "Sarah", "Sean", "Walt", "Yang"]

Trying to capitalize the first character in array of strings, why this is not working?

You have to actually re-assign the array element:

    for(var i = 1 ; i < newArr.length ; i++){
        newArr[i] = newArr[i].charAt(0).toUpperCase();
    }

The "toUpperCase()" function returns the new string but does not modify the original.

You might want to check to make sure that newArr[i] is the empty string first, in case you get an input string with two consecutive dashes.

edit — noted SO contributor @lonesomeday correctly points out that you also need to glue the rest of each string back on:

         newArr[i] = newArr[i].charAt(0).toUpperCase() + newArr[i].substr(1);