PatsyError：错误评估因素：NameError：

Question

I am an absolute newbie in Python programming and currently learning basic statistics on it.

I am facing a

"PatsyError: Error evaluating factor: NameError:"

on a code with pred = model.predict(pd.DataFrame(calo['wt'])

Below is my code:

 # For reading data set # importing necessary libraries import pandas as pd import numpy as np import matplotlib.pyplot as plt # reading a csv file using pandas library calo=pd.read_csv("/Users/Sanjeev/Desktop/Excel R Assignments/Simple Linear Regression/calories_consumed.csv") calo.columns = ['wt','cal'] np.corrcoef(calo.wt,calo.cal) plt.plot(calo.wt,calo.cal,"bo");plt.xlabel("WEIGHT");plt.ylabel("CALORIES") # For preparing linear regression model we need to import the statsmodels.formula.api import statsmodels.formula.api as smf model = smf.ols("wt~cal",data=calo).fit() # For getting coefficients of the varibles used in equation model.params # P-values for the variables and R-squared value for prepared model model.summary() model.conf_int(0.05) # 95% confidence interval pred = model.predict(pd.DataFrame(calo['wt']))

This throws up an error:

 Traceback (most recent call last): File "<ipython-input-43-4fcbf1ee1921>", line 1, in <module> pred = model.predict(pd.DataFrame(calo['wt'])) File "/anaconda3/lib/python3.7/site-packages/statsmodels/base/model.py", line 837, in predict exog = dmatrix(design_info, exog, return_type="dataframe") File "/anaconda3/lib/python3.7/site-packages/patsy/highlevel.py", line 291, in dmatrix NA_action, return_type) File "/anaconda3/lib/python3.7/site-packages/patsy/highlevel.py", line 169, in _do_highlevel_design return_type=return_type) File "/anaconda3/lib/python3.7/site-packages/patsy/build.py", line 888, in build_design_matrices value, is_NA = _eval_factor(factor_info, data, NA_action) File "/anaconda3/lib/python3.7/site-packages/patsy/build.py", line 63, in _eval_factor result = factor.eval(factor_info.state, data) File "/anaconda3/lib/python3.7/site-packages/patsy/eval.py", line 566, in eval data) File "/anaconda3/lib/python3.7/site-packages/patsy/eval.py", line 551, in _eval inner_namespace=inner_namespace) File "/anaconda3/lib/python3.7/site-packages/patsy/compat.py", line 43, in call_and_wrap_exc exec("raise new_exc from e") File "<string>", line 1, in <module> PatsyError: Error evaluating factor: NameError: name 'cal' is not defined wt~cal ^^^

Need your help to resolve this.

Thanks in advance. :)

Answer 1

Looking at the statsmodels API here , it looks like they expect the parameters as input, rather than the covariates.

So what you probably want is

pred = model.predict(model.params)

Answer 2

您需要根据您将要决定的因变量（y）模型 = statsmodels.formula.api.ols('y ~x ',data=df) model.predict(pd.DataFrame(df['x) ']))

Answer 3

I was having this problem. I was doing something like this:

for _, i in frame.iterrows()
    model.predict(i)

This doesn't provide it with the necessary headers. You have to do this:

for _, i in frame.iterrows()
    model.predict(pd.DataFrame([i]))