Question

我正在尝试创建一个程序，该程序将接受一个字符串并将其反转并用其免费字符替换它。

例如，如果字符串＆＃34; ATTGCC＆＃34;输入时，方法reverse_it应输出＆＃34; GGCAAT＆＃34;。

＆＃34; A＆＃34;取而代之的是＆＃34; T＆＃34;和＆＃34; T＆＃34;被＆＃34; A＆＃34;取代。＆＃34; C＆＃34;取而代之的是＆＃34; G＆＃34;和＆＃34; G＆＃34;被＆＃34; C＆＃34;。

取代

这是我的代码：

class DNA
  def initialize (nucleotide)
    @nucleotide = nucleotide
  end
  def reverse_it()
    puts nucleotide.reverse.gsub("C", "G").gsub("G", "C").gsub("A", "T").gsub("T", "A")
  end
  protected

  attr_reader :nucleotide
end
dna1 = DNA.new("ATTGCC")
dna1.reverse_it

问题是gsub替换所有出现的字符，sub仅替换字符串中第一个字符实例。是否有内置方法使该程序有效？

Answer 1

您可能正在寻找tr，因此在您的方法中代替public class CarTreeNode : TreeNode { // ...plus, clone all the other constructors public CarTreeNode(CarProperties car) :base(car.name) { Car = car; } private CarProperties _car; public CarProperties Car { get { return _car; } set { _car = value; // Let it throw an exception if value was null base.Text = Car.name; } } } ... snip ... // Regrettably, TreeNodeCollection.AddRange() is an old-fashioned method // that takes an array treeView1.Nodes.AddRange(cars.Select(car => new CarTreeNode(car)).ToArray()); ... snip ... private void treeView1_AfterSelect(object sender, TreeViewEventArgs e) { var ctn = e.Node as CarTreeNode; // In real life there's no reason you'd ever want to replace any car // that the user clicks on, but it demonstrates the principle. ctn.Car = new CarProperties() { name = "Aston Martin Vanquish" }; }，例如：

gsub

Answer 2

如果有许多字母对要反转，你可以节省一些打字并减少错误输入的机会，如下所示。

n = 785

，当然还有：

function minMax(items) 
{
    return [items.reduce((prev, curr)=> Math.min(prev, curr)),
            items.reduce((prev, curr)=> Math.max(prev, curr))]
}

如何用A替换字符A和T和T.

2 个答案: