我正在尝试从字符串中删除字符

Question

我正在进行测试，但是在测试后我会收到NULL，并且正在接收一个ostertionfailedError

    assertEquals("", this.myCustomString.remove(""));
    
    this.myCustomString.setString(null);
    assertEquals("", this.myCustomString.remove(""));
    
    this.myCustomString.setString("my lucky numbers are 6, 8, and 19.");
    assertEquals("my lucky numbes e 6, 8, nd 19.", this.myCustomString.remove("ra6"));

public String remove（String arg）{//从字符串中删除指定的字符

       if (myString == null || myString == "") {

           return this.myString;

           }

           if (myString != null) {

           this.myString = myString.replaceAll(arg,"");

           return myString;

           }
          
           return myString;
        
           
   }

Answer 1

这应该有帮助

    String result = "";

       if (myString == null || myString == "") {
           return ""; 
       }
       //places the String arg into a character array
         char[] c = arg.toCharArray();
  // then use a for loop to check if there is only letters in the string arg
  // after we have checked to see if there is only letters when remove anything that is not letters
       for(int i= 0; i< c.length; i++){
             if (Character.isLetter(c[i])) {
                        result = result + c[i];
                    }
                  }
 // when then use the result from above and place it into its own character array, we then use the characters
 // from the array to be replaced by blank

         for (char ch : result.toCharArray()) {
                 myString = myString.replace(String.valueOf(ch), "");
            }
                  
            
                  return myString;
                 
                }