如何正确迭代两个循环

Question

我想将我的字符串替换为其他字符串，但没有很多迹象。例如，我有“我想成为 !#$%@!_”，它应该 return “Iwanttobe”。这以某种方式起作用，但不幸的是它迭代了第一个循环（第一个字符），然后迭代了整个第二个循环。我希望它遍历所有第一个，然后遍历所有第二个，并根据

添加字符到我的新 table

这是我的方法：

public static List<Character> count (String str){

    char[] chars = str.toCharArray();
    List<Character> charsWithOutSpecial = new ArrayList<>();
    char[] specialChars = {' ','!','"','#','$','%','&','(',')','*','+',',',
            '-','.','/',':',';','<','=','>','?','@','[',']','^','_',
            '`','{','|','}','~','\','\''};

    for (int i = 0; i < specialChars.length; i++) {
        for (int j = 0; j < chars.length; j++) {
            if(specialChars[i] != chars[j]){
                charsWithOutSpecial.add(chars[j]);
            }
        }
    }
    return charsWithOutSpecial;
}

Answer 1

这应该可以完成工作：

str = str.replaceAll("[^A-Za-z0-9]", ""); // replace all characters that are not numbers or characters with an empty string.

Answer 2

您可以这样修正您的方法：

public static List<Character> count (String str){

    char[] chars = str.toCharArray();
    List<Character> charsWithOutSpecial = new ArrayList<>();
    char[] specialChars = {' ','!','"','#','$','%','&','(',')','*','+',',',
            '-','.','/',':',';','<','=','>','?','@','[',']','^','_',
            '`','{','|','}','~','\','\''};

    for (int i = 0; i < chars.length; i++) {
        boolean isCharValid = true;
        // iterating over the special chars
        for (int j = 0; j < specialChars.length; j++) { 
            if(specialChars[j] == chars[i]){
                // we identified the char as special 
                isCharValid = false; 
            }
        }

        if(isCharValid){
            charsWithOutSpecial.add(chars[i]);
        }
    }
    return charsWithOutSpecial;
}

Answer 3

你想要的正则表达式可能是 [^a-zA-Z]

但是你也可以使用两个循环来做到这一点

StringBuilder str2 = new StringBuilder();
  for (int j = 0; j < chars.length; j++) {
    boolean special = false;
    for (int i = 0; i < specialChars.length; i++) {
        if(specialChars[i] == chars[j]){
            special = true;
            break;
        }
    }
    if (!special) str2.append(chars[j]);
}

如何正确迭代两个循环

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