去掉字符串中的数字并保留几个字符

import re

def remove_digits_keep_chars(string, num_chars):
    # 使用正则表达式去掉数字
    string_without_digits = re.sub(r'\d', '', string)
    # 保留指定数量的字符
    result = string_without_digits[:num_chars]
    return result

def remove_digits_keep_chars_loop(string, num_chars):
    # 循环遍历字符串，去掉数字并保留指定数量的字符
    result = ''
    count = 0
    for char in string:
        if not char.isdigit():
            result += char
            count += 1
            if count == num_chars:
                break
    return result

# 示例用法
string = "abc123def456"
num_chars = 5

result_regex = remove_digits_keep_chars(string, num_chars)
result_loop = remove_digits_keep_chars_loop(string, num_chars)

print("使用正则表达式去掉数字并保留{}个字符：{}".format(num_chars, result_regex))
print("使用循环遍历去掉数字并保留{}个字符：{}".format(num_chars, result_loop))