为什么Python说一个值不存在，而实际上它确实存在？

fnvucqvd  于 2023-01-24  发布在  Python
关注(0)|答案(2)|浏览(125)

简短说明：

主要问题是，每当我运行下面的代码，我得到下面的错误：

import statsmodels.api as sm
from statsmodels.formula.api import ols    
def onewayanaova (csv, vars, x="x-axis", y="y-axis"):
        df = pd.read_csv(csv, delimiter=",") 
        df_melt = pd.melt(df.reset_index(), id_vars=['index'], value_vars=vars)
        df_melt.columns = ['index', {x}, {y}]
        model = ols(f'{y} ~ C({x})', data=df_melt).fit()
        anova_table = sm.stats.anova_lm(model, typ=2)
        print("The One-Way Anova Test Values are:\n")
        print(anova_table)
onewayanaova("Book1.csv", ["a","b","c"])

错误为：

Traceback (most recent call last):
  File "pandas\_libs\hashtable_class_helper.pxi", line 5231, in pandas._libs.hashtable.PyObjectHashTable.map_locations
TypeError: unhashable type: 'set'
Exception ignored in: 'pandas._libs.index.IndexEngine._call_map_locations'
Traceback (most recent call last):
  File "pandas\_libs\hashtable_class_helper.pxi", line 5231, in pandas._libs.hashtable.PyObjectHashTable.map_locations
TypeError: unhashable type: 'set'
Traceback (most recent call last):
  File "C:\Users\mghaf\AppData\Local\Packages\PythonSoftwareFoundation.Python.3.9_qbz5n2kfra8p0\LocalCache\local-packages\Python39\site-packages\patsy\compat.py", line 36, in call_and_wrap_exc
    return f(*args, **kwargs)
  File "C:\Users\mghaf\AppData\Local\Packages\PythonSoftwareFoundation.Python.3.9_qbz5n2kfra8p0\LocalCache\local-packages\Python39\site-packages\patsy\eval.py", line 165, in eval
    return eval(code, {}, VarLookupDict([inner_namespace]
  File "<string>", line 1, in <module>
NameError: name 'axis' is not defined

The above exception was the direct cause of the following exception:

Traceback (most recent call last):
  File "c:\Users\mghaf\Desktop\Python Codes\ReMan Edu\test.py", line 3, in <module>
    mn.onewayanaova("Book1.csv", ["a","b","c"])
  File "c:\Users\mghaf\Desktop\Python Codes\ReMan Edu\maincode.py", line 154, in onewayanaova
    model = ols(f'{y} ~ C({x})', data=df_melt).fit()
  File "C:\Users\mghaf\AppData\Local\Packages\PythonSoftwareFoundation.Python.3.9_qbz5n2kfra8p0\LocalCache\local-packages\Python39\site-packages\statsmodels\base\model.py", line 200, in from_formula
    tmp = handle_formula_data(data, None, formula, depth=eval_env,
  File "C:\Users\mghaf\AppData\Local\Packages\PythonSoftwareFoundation.Python.3.9_qbz5n2kfra8p0\LocalCache\local-packages\Python39\site-packages\statsmodels\formula\formulatools.py", line 63, in handle_formula_data
    result = dmatrices(formula, Y, depth, return_type='dataframe',
  File "C:\Users\mghaf\AppData\Local\Packages\PythonSoftwareFoundation.Python.3.9_qbz5n2kfra8p0\LocalCache\local-packages\Python39\site-packages\patsy\highlevel.py", line 309, in dmatrices
    (lhs, rhs) = _do_highlevel_design(formula_like, data, eval_env,
  File "C:\Users\mghaf\AppData\Local\Packages\PythonSoftwareFoundation.Python.3.9_qbz5n2kfra8p0\LocalCache\local-packages\Python39\site-packages\patsy\highlevel.py", line 164, in _do_highlevel_design
    design_infos = _try_incr_builders(formula_like, data_iter_maker, eval_env,
  File "C:\Users\mghaf\AppData\Local\Packages\PythonSoftwareFoundation.Python.3.9_qbz5n2kfra8p0\LocalCache\local-packages\Python39\site-packages\patsy\highlevel.py", line 66, in _try_incr_builders
    return design_matrix_builders([formula_like.lhs_termlist,
  File "C:\Users\mghaf\AppData\Local\Packages\PythonSoftwareFoundation.Python.3.9_qbz5n2kfra8p0\LocalCache\local-packages\Python39\site-packages\patsy\build.py", line 693, in design_matrix_builders
    cat_levels_contrasts) = _examine_factor_types(all_factors,
  File "C:\Users\mghaf\AppData\Local\Packages\PythonSoftwareFoundation.Python.3.9_qbz5n2kfra8p0\LocalCache\local-packages\Python39\site-packages\patsy\build.py", line 443, in _examine_factor_types
    value = factor.eval(factor_states[factor], data)
  File "C:\Users\mghaf\AppData\Local\Packages\PythonSoftwareFoundation.Python.3.9_qbz5n2kfra8p0\LocalCache\local-packages\Python39\site-packages\patsy\eval.py", line 564, in eval
    return self._eval(memorize_state["eval_code"],
  File "C:\Users\mghaf\AppData\Local\Packages\PythonSoftwareFoundation.Python.3.9_qbz5n2kfra8p0\LocalCache\local-packages\Python39\site-packages\patsy\eval.py", line 547, in _eval
    return call_and_wrap_exc("Error evaluating factor",
  File "C:\Users\mghaf\AppData\Local\Packages\PythonSoftwareFoundation.Python.3.9_qbz5n2kfra8p0\LocalCache\local-packages\Python39\site-packages\patsy\compat.py", line 43, in call_and_wrap_exc
    exec("raise new_exc from e")
  File "<string>", line 1, in <module>
patsy.PatsyError: Error evaluating factor: NameError: name 'axis' is not defined
    y-axis ~ C(x-axis)
             ^^^^^^^^^

我想是我在def onewayanaova (csv, vars, x="x-axis", y="y-axis"):中设置的X和Y变量，也许我需要改变它，这样我就不会得到错误了？
如果您想了解更详细的描述，请阅读下面的内容。

详细说明：

我正在尝试做一个单向Anova测试。然而，主要的问题是Python一直说有一个NameError，而且我的一个值没有定义。
我正在运行下面的代码：

import statsmodels.api as sm
from statsmodels.formula.api import ols    
def onewayanaova (csv, vars, x="x-axis", y="y-axis"):
        df = pd.read_csv(csv, delimiter=",") 
        df_melt = pd.melt(df.reset_index(), id_vars=['index'], value_vars=vars)
        df_melt.columns = ['index', {x}, {y}]
        model = ols(f'{y} ~ C({x})', data=df_melt).fit()
        anova_table = sm.stats.anova_lm(model, typ=2)
        print("The One-Way Anova Test Values are:\n")
        print(anova_table)

以及：

import maincode as mn
mn.onewayanaova("Book1.csv", ["a","b","c"])

我得到以下错误（第一个代码保存到名为manicode.py的文件中，第二个代码保存到名为test.py的文件中。"Book1.csv"与它们位于同一文件夹中）。

Traceback (most recent call last):
  File "pandas\_libs\hashtable_class_helper.pxi", line 5231, in pandas._libs.hashtable.PyObjectHashTable.map_locations
TypeError: unhashable type: 'set'
Exception ignored in: 'pandas._libs.index.IndexEngine._call_map_locations'
Traceback (most recent call last):
  File "pandas\_libs\hashtable_class_helper.pxi", line 5231, in pandas._libs.hashtable.PyObjectHashTable.map_locations
TypeError: unhashable type: 'set'
Traceback (most recent call last):
  File "C:\Users\mghaf\AppData\Local\Packages\PythonSoftwareFoundation.Python.3.9_qbz5n2kfra8p0\LocalCache\local-packages\Python39\site-packages\patsy\compat.py", line 36, in call_and_wrap_exc
    return f(*args, **kwargs)
  File "C:\Users\mghaf\AppData\Local\Packages\PythonSoftwareFoundation.Python.3.9_qbz5n2kfra8p0\LocalCache\local-packages\Python39\site-packages\patsy\eval.py", line 165, in eval
    return eval(code, {}, VarLookupDict([inner_namespace]
  File "<string>", line 1, in <module>
NameError: name 'axis' is not defined

The above exception was the direct cause of the following exception:

Traceback (most recent call last):
  File "c:\Users\mghaf\Desktop\Python Codes\ReMan Edu\test.py", line 3, in <module>
    mn.onewayanaova("Book1.csv", ["a","b","c"])
  File "c:\Users\mghaf\Desktop\Python Codes\ReMan Edu\maincode.py", line 154, in onewayanaova
    model = ols(f'{y} ~ C({x})', data=df_melt).fit()
  File "C:\Users\mghaf\AppData\Local\Packages\PythonSoftwareFoundation.Python.3.9_qbz5n2kfra8p0\LocalCache\local-packages\Python39\site-packages\statsmodels\base\model.py", line 200, in from_formula
    tmp = handle_formula_data(data, None, formula, depth=eval_env,
  File "C:\Users\mghaf\AppData\Local\Packages\PythonSoftwareFoundation.Python.3.9_qbz5n2kfra8p0\LocalCache\local-packages\Python39\site-packages\statsmodels\formula\formulatools.py", line 63, in handle_formula_data
    result = dmatrices(formula, Y, depth, return_type='dataframe',
  File "C:\Users\mghaf\AppData\Local\Packages\PythonSoftwareFoundation.Python.3.9_qbz5n2kfra8p0\LocalCache\local-packages\Python39\site-packages\patsy\highlevel.py", line 309, in dmatrices
    (lhs, rhs) = _do_highlevel_design(formula_like, data, eval_env,
  File "C:\Users\mghaf\AppData\Local\Packages\PythonSoftwareFoundation.Python.3.9_qbz5n2kfra8p0\LocalCache\local-packages\Python39\site-packages\patsy\highlevel.py", line 164, in _do_highlevel_design
    design_infos = _try_incr_builders(formula_like, data_iter_maker, eval_env,
  File "C:\Users\mghaf\AppData\Local\Packages\PythonSoftwareFoundation.Python.3.9_qbz5n2kfra8p0\LocalCache\local-packages\Python39\site-packages\patsy\highlevel.py", line 66, in _try_incr_builders
    return design_matrix_builders([formula_like.lhs_termlist,
  File "C:\Users\mghaf\AppData\Local\Packages\PythonSoftwareFoundation.Python.3.9_qbz5n2kfra8p0\LocalCache\local-packages\Python39\site-packages\patsy\build.py", line 693, in design_matrix_builders
    cat_levels_contrasts) = _examine_factor_types(all_factors,
  File "C:\Users\mghaf\AppData\Local\Packages\PythonSoftwareFoundation.Python.3.9_qbz5n2kfra8p0\LocalCache\local-packages\Python39\site-packages\patsy\build.py", line 443, in _examine_factor_types
    value = factor.eval(factor_states[factor], data)
  File "C:\Users\mghaf\AppData\Local\Packages\PythonSoftwareFoundation.Python.3.9_qbz5n2kfra8p0\LocalCache\local-packages\Python39\site-packages\patsy\eval.py", line 564, in eval
    return self._eval(memorize_state["eval_code"],
  File "C:\Users\mghaf\AppData\Local\Packages\PythonSoftwareFoundation.Python.3.9_qbz5n2kfra8p0\LocalCache\local-packages\Python39\site-packages\patsy\eval.py", line 547, in _eval
    return call_and_wrap_exc("Error evaluating factor",
  File "C:\Users\mghaf\AppData\Local\Packages\PythonSoftwareFoundation.Python.3.9_qbz5n2kfra8p0\LocalCache\local-packages\Python39\site-packages\patsy\compat.py", line 43, in call_and_wrap_exc
    exec("raise new_exc from e")
  File "<string>", line 1, in <module>
patsy.PatsyError: Error evaluating factor: NameError: name 'axis' is not defined
    y-axis ~ C(x-axis)
             ^^^^^^^^^

我看到的主要错误是我将X和Y变量命名为：但是我不明白为什么这会给我一个错误，因为我从中制作了一个看起来非常整洁的箱线图（但我知道X和Y被用作轴标题）：

def boxplot (csv, vars, x="x-axis", y="y-axis"):
    #https://www.reneshbedre.com/blog/anova.html
    df = pd.read_csv(csv, delimiter=",") 
    df_melt = pd.melt(df.reset_index(), id_vars=['index'], value_vars=vars)
    df_melt.columns = ['index', x, y]
    ax = sns.boxplot(x=x, y=y, data=df_melt, color='#99c2a2')
    ax = sns.swarmplot(x=x, y=y, data=df_melt, color='#7d0013')
    plt.show()

但是，每当我从别人那里写这段代码时，它都会给出我想要的输出：

import statsmodels.api as sm
from statsmodels.formula.api import ols
import pandas as pd
df = pd.read_csv("https://reneshbedre.github.io/assets/posts/anova/onewayanova.txt", sep="\t")
df_melt = pd.melt(df.reset_index(), id_vars=['index'], value_vars=['A', 'B', 'C', 'D'])
df_melt.columns = ['index', 'treatments', 'value']
model = ols('value ~ C(treatments)', data=df_melt).fit()
anova_table = sm.stats.anova_lm(model, typ=2)
print(anova_table)

我用上面的代码得到的输出：

sum_sq    df         F    PR(>F)
C(treatments)  3010.95   3.0  17.49281  0.000026
Residual        918.00  16.0       NaN       NaN

主要的问题是我需要改变model = ols('value ~ C(treatments)', data=df_melt).fit()和df_melt.columns = ['index', 'treatments', 'value']的值，因为大多数数据集没有'treatments', 'value'作为他们的数据库。如果你想知道我的. csv文件有什么是这样的：

  1. a、b和c的列标题
    1.一列相等数量的数字
    我的主要问题是：
    • 请尝试帮助我理解为什么我不能用X和Y替换'value ~ C(treatments)'!**

代码来源：https://www.reneshbedre.com/blog/anova.html

python

2条答案

按热度按时间
sczxawaw

sczxawaw1#

在statmodels公式中，需要对变量加引号（即 Dataframe 中的列），当它们包含特殊字符（如-）时。请查看documentation，您的术语“x-axis”被解释为“x”-“axis”。引用变量可以使用Q()转换完成。请确保用不同的用于字符串的（单/双）引号：

model = ols(f'Q("{y}") ~ C(Q("{x}"))', data=df_melt).fit()
赞(0）分享  回复(0）举报  2023-01-24
lxkprmvk

lxkprmvk2#

看起来model = ols('value ~ C(treatments)', data=df_melt).fit()不能有变量subsitute（就像我在model = ols(f'{y} ~ C({x})', data=df_melt).fit()中那样），如果我使用model = ols(f'Q("{y}") ~ C(Q("{x}"))', data=df_melt).fit()也是如此，正如@Rob提到的。
因此，为了使它工作并有自己的名称，我只需要根据model = ols('value ~ C(treatments)', data=df_melt).fit()重命名df_melt.columns = ['index', 'treatments', 'value']（其中'treatments', 'value'在两行代码中是相同的）。

赞(0）分享  回复(0）举报  2023-01-24
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