替换字符串中字符的有效方法(java)? [英] Efficient way to replace chars in a string (java)?

问题描述

我正在编写一个小型 JAVA 程序，它:

I'm writing a small JAVA program which:

• 将文本作为字符串
• 接受 2 个字符数组

我尝试做的事情听起来像是查找和替换"，但事实并非如此，所以我认为清除它很重要.

What im trying to do will sound like "find and replace" but it is not the same so i thought its important to clear it.

无论如何，我想获取此文本，查找第一个数组中的任何字符是否与文本中的字符匹配，如果匹配，则将其替换为第二个字符数组中的匹配字符(根据索引).

Anyway I want to take this text, find if any char from the first array match a char in the text and if so, replace it with the matching char (according to index) from the second char array.

我会用一个例子来解释:假设我的文本(字符串)是:java 太棒了！"；我有 2 个数组 (char[]):absm"和!@*$".

I'll explain with an example: lets say my text (String) is: "java is awesome!"; i have 2 arrays (char[]): "absm" and "!@*$".

希望的结果是将 'a' 改为 '!', 'b' 到 '@' 等等..意味着结果文本将是:

The wished result is to change 'a' to '!' , 'b' to '@' and so on.. meaning the resulted text will be:

java 太棒了！"改为 -> "j@v@ i* @w*o$e!"

最有效的方法是什么?为什么?我想过循环文本，但后来发现效率不高.

What is the most efficient way of doing this and why? I thought about looping the text, but then i found it not so efficient.

(StringBuilder/String 类可以使用)

(StringBuilder/String class can be used)

推荐答案

StringBuilder sb = new StringBuilder(text);
    for(int i = 0; i<text.length(); i ++)
    {
        for (int j = 0; j < firstCharArray.length;j++)
        {
            if (sb.charAt(i) == firstCharArray[j])
            {
                sb.setCharAt(i, secondCharArray[j]);
                break;
            }

        }
    }

这种方式很有效，因为它使用 StringBuilder 来改变字符(如果你使用字符串，你每次都必须创建新的，因为它们是不可变的.)而且它最大限度地减少了你必须做的传递量(1 通过文本字符串，n 通过第一个数组 where n = text.length())

This way is efficient because it uses a StringBuilder to change the characters in place (if you used Strings you would have to create new ones each time because they are immutable.) Also it minimizes the amount of passes you have to do (1 pass through the text string and n passes through the first array where n = text.length())

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