如何从 ArrayList 中获取最大值

Question

I'm trying to get highest price of a product. I'm able to store the prices in an object. I want to know how to get the maximum value from that object. Below is my code!

public class amazon {
    static WebDriver driver;

    public static void main(String[] args) throws Exception {
        System.setProperty("webdriver.chrome.driver", "C://Selenium/chromedriver.exe");
        driver = new ChromeDriver();
        driver.get("xyzzz.com");
        driver.manage().timeouts().implicitlyWait(10, TimeUnit.SECONDS);
        amazon az = new amazon();
        az.run();

        }

    public void run() throws Exception {


            List<Object> obj = new ArrayList<Object>();

            List<WebElement> tag = driver.findElements(By.xpath("//span[@class='a-price-whole']"));

            int i;
            for(i=0; i<tag.size(); i++) {

                obj.add(tag.get(i).getText());

            }

            System.out.println(obj);
            driver.close();

    }

Output i have..

[64,900, 99,900, 1,23,900, 64,900, 64,900, 69,900, 64,900, 64,900, 1,23,900, 52,900]

Answer 1

Map the strings to ints (or longs, or some type of currency), then you can get the max using a Comparator

int max = driver.findElements(By.xpath("//span[@class='a-price-whole']")).stream() 
    .map(WebElement::getText)
    .map(s -> s.replace(",", ""))
    .map(Integer::parseInt)
    .max(Integer::compare)
    .get();

Answer 2

You first need to convert the numbers to int, and than you can use Collections.max on the list

List<Integer> prices = new ArrayList<>();
List<WebElement> tags = driver.findElements(By.xpath("//span[@class='a-price-whole']"));
for (WebElement tag: tags) {
    prices.add(Integer.parseInt(tag.getText().replace(",", "")));
}
System.out.print(Collections.max(prices)); // 123900

Answer 3

create an int and call it max (=0), run on each element of the list using a loop (for loop recommended), on each element, check if its bigger than max, if yes, put the value in max, here is a little code, in case the list is called "list", change it to whatever you want

int max=0;
for (int i : list){
  if (i >max)
    max=i;
}
System.out.println(max) //print the maximum value of the array