使用字符串格式在我的数字中添加美元符号和逗号

def format_number(number):
    # 将数字转换为字符串
    number_str = str(number)
    
    # 检查是否为负数
    is_negative = False
    if number_str.startswith('-'):
        is_negative = True
        number_str = number_str[1:]
    
    # 检查是否有小数部分
    decimal_index = number_str.find('.')
    if decimal_index != -1:
        decimal_part = number_str[decimal_index:]
        number_str = number_str[:decimal_index]
    else:
        decimal_part = ''
    
    # 添加逗号
    formatted_number = ''
    count = 0
    for i in range(len(number_str)-1, -1, -1):
        formatted_number = number_str[i] + formatted_number
        count += 1
        if count % 3 == 0 and i != 0:
            formatted_number = ',' + formatted_number
    
    # 添加美元符号和负号（如果有）
    if is_negative:
        formatted_number = '-' + formatted_number
    formatted_number = '$' + formatted_number
    
    # 拼接小数部分（如果有）
    formatted_number += decimal_part
    
    return formatted_number

# 示例用法
number = 1234567.89
formatted_number = format_number(number)
print(formatted_number)