TypeError：无法从dtype（'

Question

When trying to plot the outliers using different colours on a scatterplot I came across this error:

TypeError: Cannot cast array data from dtype('U1') to dtype('float64') according to the rule 'safe'

My code:

import statsmodels.api as sm
import pandas as pd
import matplotlib.pyplot as plt
import numpy as np

CRP = pd.read_csv('CarsProp.csv')

priceMean = CRP.price.mean()
priceStd = CRP.price.std()   

CRP['isOutlierPrice'] = np.nan
testColumn1 = abs(CRP.price - priceMean) > 2*priceStd

for i, value in enumerate(testColumn1):
    if value == True:
        CRP['isOutlierPrice'][i] = 1

mileageMean = CRP.mileage.mean()
mileageStd = CRP.mileage.mean()

CRP['isOutlierMileage'] = np.nan
testColumn2 = abs(CRP.mileage - mileageMean) > 2*priceStd

for i, value in enumerate(testColumn2):
    if value == True:
        CRP['isOutlierMileage'][i] = 1

outlierPmsJoint = ((CRP['isOutlierPrice'] == 1) | (CRP['isOutlierMileage'] == 1))

colorChoiceDict = {True: (1.0, 0.55, 0.0, 1.0), 
              False: (0.11, 0.65, 0.72, 0.1)}

colorCol = [colorChoiceDict[val] for val in outlierPmsJoint]

PriceFloat = [float(val) for val in CRP.price]
MileageFloat = [float(val) for val in CRP.mileage]

plt.figure()
plt.scatter(PriceFloat, MileageFloat, c = colorCol, linewidth='0')
plt.set_title('Price vs. Mileage with outliers')  

Does anyone know where the problem is and how to solve it? Thank you,

Answer 1

The problem was in the scatter plot line. It should be:

plt.scatter(PriceFloat, MileageFloat, c = colorCol, linewidth=0)

I was putting the line width arg in inverted comas, which did not yield an output. However, the error message was very misleading. Next time I probably will pay less attention to the error message when debugging.