预算饼图生成失败：ValueError非负值错误求助

错误原因 #

1. 输入未转数值，字符串拼接导致计算错误：input()函数返回的是字符串类型，直接用+拼接各支出项不是数值相加，而是字符串拼接。比如输入 groceries=100、gas=50，inputted_groceries + inputted_gas会得到"10050"，转成float后数值远大于收入，导致total_left变成负数，触发Matplotlib饼图要求所有扇区数值非负的检查。
2. 饼图数据类型混合：构建y数组时，前几个元素还是字符串类型，和后面的total_left（float）混合，numpy数组会统一成字符串类型，饼图无法正确解析，同时负数的存在直接抛出错误。

解决方法 #

步骤1：将所有输入转为数值类型 #

把每个input()的结果直接转成float，确保后续计算都是数值运算。

步骤2：修正总支出的计算逻辑 #

用数值相加替代字符串拼接，得到正确的总支出。

步骤3：添加超支检查（可选） #

如果总支出超过收入，total_left会是负数，此时可以提示用户超支，避免饼图报错。

修正后的完整代码 #

import matplotlib.pyplot as plt
import numpy as np

# 所有输入直接转为float类型
inputted_payment = float(input("Type in how much money you made this month. Don't type any letters or symbols. Type decimals if needed.  "))
inputted_groceries = float(input("Type in how much money you spent on groceries this month. Don't type any letters or symbols. Type decimals if needed.  "))
inputted_gas = float(input("Type in how much money you spent on gas this month. Don't type any letters or symbols. Type decimals if needed.  "))
inputted_bills = float(input("Type in how much money you spent on bills. Don't type any letters or symbols. Type decimals if needed.  "))
inputted_restaurants = float(input("Type in how much money you spent on restaurants. Don't type any letters or symbols, Type decimals if needed.  "))
inputted_other_things = float(input("Type in how much money you spent on other things. Don't type any letters or symbols. Type decimals if needed.  "))

# 数值相加计算总支出
total_spent = inputted_bills + inputted_other_things + inputted_gas + inputted_groceries + inputted_restaurants
total_left = inputted_payment - total_spent

# 检查是否超支，避免负数
if total_left < 0:
    print("Warning: You spent more than you earned this month!")
    total_left = 0

# 构建全数值类型的饼图数据
y = np.array([inputted_groceries, inputted_gas, inputted_bills, inputted_restaurants, inputted_other_things, total_left])
mylabels = ["Groceries", "Gas", "Bills", "Restaurants", "Other Things", "Money Left"]

print('\nTotal Spendings')
plt.pie(y, labels=mylabels, autopct='%1.1f%%')  # 可选：添加百分比显示
plt.title("Monthly Budget Breakdown")
plt.show()

关键修改点说明 #

• 每个输入都用float()转换，确保后续计算是数值运算。
• 总支出计算改为数值相加，得到正确的金额。
• 添加超支检查，避免total_left为负数导致饼图报错。
• 可选添加autopct参数显示扇区百分比，让饼图更直观。

内容的提问来源于stack exchange，提问作者MiniSkoot32