统计字符串中的字母数，空格，数字和其他字符

统计字符串中的字母、空格、数字和其他字符通常涉及到对字符串内容进行遍历，并依据字符类别来进行计数。以下是几种常见语言的简单示例：

1. **Python**:

def count_chars(s):
    counts = {'letters': 0, 'spaces': 0, 'numbers': 0, 'other': 0}
    for char in s:
        if char.isalpha():
            counts['letters'] += 1
        elif char.isspace():
            counts['spaces'] += 1
        elif char.isdigit():
            counts['numbers'] += 1
        else:
            counts['other'] += 1
    return counts

# 示例用法
s = "Hello, World! 123"
print(count_chars(s))

2. **JavaScript**:

function countChars(str) {
    var counts = { letters: 0, spaces: 0, numbers: 0, other: 0 };
    for (var i = 0; i < str.length; i++) {
        var char = str[i];
        if (/^[a-zA-Z]+$/.test(char)) {
            counts.letters++;
        } else if (char === ' ') {
            counts.spaces++;
        } else if (!isNaN(char)) {
            counts.numbers++;
        } else {
            counts.other++;
        }
    }
    return counts;
}

// 示例用法
let s = "Hello, World! 123";
console.log(countChars(s));

3. **Java**:

public Map<String, Integer> countChars(String s) {
    Map<String, Integer> counts = new HashMap<>();
    counts.put("letters", 0);
    counts.put("spaces", 0);
    counts.put("numbers", 0);
    counts.put("other", 0);

    for (char c : s.toCharArray()) {
        switch (Character.getType(c)) {
            case CHAR_ALPHANUMERIC:
                if (Character.isLetter(c)) counts.put("letters", counts.getOrDefault("letters", 0) + 1);
                break;
            case SPACE:
                counts.put("spaces", counts.getOrDefault("spaces", 0) + 1);
                break;
            default:
                counts.put("numbers" if Character.isDigit(c) else "other", counts.getOrDefault(key, 0) + 1);
        }
    }
    return counts;
}

// 示例用法
String s = "Hello, World! 123";
System.out.println(countChars(s));