几个简单代码优化方法

Posted 2022-11-27 xiaogeformax

几个简单代码优化方法

提取代码

提取前

void renderBanner() 
  if ((platform.toUpperCase().indexOf("MAC") > -1) &&
       (browser.toUpperCase().indexOf("IE") > -1) &&
        wasInitialized() && resize > 0 )
  
    // do something
  

提取后

void renderBanner() 
  final boolean isMacOs = platform.toUpperCase().indexOf("MAC") > -1;
  final boolean isIE = browser.toUpperCase().indexOf("IE") > -1;
  final boolean wasResized = resize > 0;

  if (isMacOs && isIE && wasInitialized() && wasResized) 
    // do something
  

Inline Temp

内联变量之前，减少代码量，方便查看。

double hasDiscount(Order order) 
  double basePrice = order.basePrice();
  return (basePrice > 1000);

内联变量之后

double hasDiscount(Order order) 
  return (order.basePrice() > 1000);

Replace Temp with Query

用变量取代查询之前

double calculateTotal() 
  double basePrice = quantity * itemPrice;
  if (basePrice > 1000) 
    return basePrice * 0.95;
  
  else 
    return basePrice * 0.98;
  

用变量之后，读起来更有目的性

double calculateTotal() 
  if (basePrice() > 1000) 
    return basePrice() * 0.95;
  
  else 
    return basePrice() * 0.98;
  

double basePrice() 
  return quantity * itemPrice;

Substitute Algorithm

用算法替代之前

string FoundPerson(string[] people)

  for (int i = 0; i < people.Length; i++) 
  
    if (people[i].Equals("Don"))
    
      return "Don";
    
    if (people[i].Equals("John"))
    
      return "John";
    
    if (people[i].Equals("Kent"))
    
      return "Kent";
    
  
  return String.Empty;

用算法替代之后

string FoundPerson(string[] people)

  List<string> candidates = new List<string>() "Don", "John", "Kent";

  for (int i = 0; i < people.Length; i++) 
  
    if (candidates.Contains(people[i])) 
    
      return people[i];
    
  

  return String.Empty;