修改以上代码用if语句实现

当然，我们可以将税率分段判断的部分改写成一系列`if...elif...else`语句，以下是修改后的版本：

def calculate_tax(salary, insurance, other):
    tax_thresholds = [3000, 12000, 25000, 35000, 55000, 80000]
    tax_rates = [3, 10, 20, 25, 30, 45]
    quick_deductions = [0, 210, 1410, 2660, 4410, 7160, 15160]
    taxable_income = salary - 5000 - insurance - other
    total_tax = 0

    for threshold, rate, deduction in zip(tax_thresholds[:-1], tax_rates[:-1], quick_deductions[:-1]):
        if taxable_income > threshold:
            tax_amount = (taxable_income - threshold) * rate - deduction
            taxable_income -= threshold
        else:
            tax_amount = taxable_income * rate - deduction
            break

    # 对于最后超过80000元的部分
    if taxable_income > tax_thresholds[-1]:
        tax_amount += (taxable_income - tax_thresholds[-1]) * tax_rates[-1] - quick_deductions[-1]

    total_tax = max(0, tax_amount)  # 确保不会支付负税
    net_salary = salary - insurance - other - total_tax
    return total_tax, round(net_salary, 2)

# 样例计算
income = 9000
insurance = 1234
other = 1000
tax, actual_salary = calculate_tax(income, insurance, other)
print(f"个人所得税: {f'￥{tax:.2f}'元}")
print(f"实际到手收入: {f'￥{actual_salary:.2f}'元}")

# 结果将会按上述样例输出

在这个版本中，我们通过嵌套的`if`语句检查每个税率段，当收入超出当前阶段时就应用新的税率和速算扣除。这种方法虽然直观，但对于较大的税率表可能会显得冗长，但如果税率层级较少，它还是一个简洁有效的解决方案。