Matplotlib散点图ValueError报错求助：参数s不符合要求

原代码 #

import matplotlib.pyplot as graph

data = [147,96,106,81,48,37,15,25,41,99,160,145]

months = ["1/22", "2/22", "3/22", "4/22", "5/22", "6/22", "7/22", "8/22", "9/22", "10/22","11/22", "12/22"]

data2 = [48,50,54,59,66,71,77,78,71,61,52,47]

graph.title("Seattle (Rain Fall vs Temperature)", fontsize = 14)

graph.xlabel("Months", fontsize = 14)

graph.ylabel("Weather Level", fontsize = 14)

graph.tick_params(axis='both',labelsize = 9)

graph.scatter(data, months, color="blue", label = "Average Rain Fall")

graph.scatter(data2, months, color="red", label = "Average Temperature")

graph.legend()

graph.scatter(data, data2, months)

graph.show()

报错信息 #

runfile('C:/Users/dddst279/My Files/Google Drive/My Drive/Scatter Graph.py', wdir='C:/Users/dddst279/My Files/Google Drive/My Drive')
Traceback (most recent call last):

  File "C:\Users\dddst279\My Files\Google Drive\My Drive\Scatter Graph.py", line 14, in <module>
    graph.scatter(data, data2, months)

  File "C:\ProgramData\Anaconda3\lib\site-packages\matplotlib\pyplot.py", line 2819, in scatter
    __ret = gca().scatter(

  File "C:\ProgramData\Anaconda3\lib\site-packages\matplotlib\__init__.py", line 1412, in inner
    return func(ax, *map(sanitize_sequence, args), **kwargs)

  File "C:\ProgramData\Anaconda3\lib\site-packages\matplotlib\axes\_axes.py", line 4371, in scatter
    raise ValueError(

ValueError: s must be a scalar, or float array-like with the same size as x and y

错误原因 #

错误出在代码行graph.scatter(data, data2, months)：
Matplotlib的scatter函数第三个参数是s，用于指定散点的大小，要求是标量或者和x、y长度一致的浮点数组。你传入的months是字符串列表，完全不符合s的参数要求，因此触发了这个ValueError。

解决方案 #

根据你的需求，有两种处理方式：

方式1：如果想给降雨量与温度的对应点添加月份标签 #

删除错误的scatter调用，改用annotate循环为每个点添加标签：

# 替换原错误行
for x, y, month in zip(data, data2, months):
    graph.annotate(month, (x, y), textcoords="offset points", xytext=(0,10), ha='center')

方式2：如果该代码行是误添加的 #

直接删除graph.scatter(data, data2, months)这一行即可，前面的代码已经完成了降雨量、温度与月份的散点绘制。

修正后的完整代码示例 #

import matplotlib.pyplot as graph

data = [147,96,106,81,48,37,15,25,41,99,160,145]
months = ["1/22", "2/22", "3/22", "4/22", "5/22", "6/22", "7/22", "8/22", "9/22", "10/22","11/22", "12/22"]
data2 = [48,50,54,59,66,71,77,78,71,61,52,47]

graph.title("Seattle (Rain Fall vs Temperature)", fontsize = 14)
graph.xlabel("Months", fontsize = 14)
graph.ylabel("Weather Level", fontsize = 14)
graph.tick_params(axis='both',labelsize = 9)

graph.scatter(data, months, color="blue", label = "Average Rain Fall")
graph.scatter(data2, months, color="red", label = "Average Temperature")

# 添加月份标签（可选）
for x, y, month in zip(data, data2, months):
    graph.annotate(month, (x, y), textcoords="offset points", xytext=(0,10), ha='center')

graph.legend()
graph.show()

内容的提问来源于stack exchange，提问作者eleven