Question

我需要通过执行值的简单算术组合来使用现有列创建新列。这是我的代码。

import pandas as pd
import matplotlib as mpl
import matplotlib.pyplot as plt
import numpy as np

class Dataset():
    def __init__(self, input):
        self.choice = input
        self.file = 0

    def read(self):
        if self.choice == ("1"):
            self.file = pd.read_csv('1')
            self.file.plot(kind='bar')
            print(df)

i = (input("Pick a DataSet= "))
df = Dataset(i)
df.read()
plt.show()

我尝试过这些建议：

        #'Dataset' object does not support item assignment --> df['New Column'] = ['Reference Area'] + ['Ratio']
        #TypeError: 'Dataset' object is not subscriptable -> df['NEW COL'] = df[['Reference Area', 'Ratio']].sum(axis=1)

Answer 1

变量df的类型为DataSet，而非pandas。 pandas变量位于DataSet类（变量self.file）内，因此您应该能够执行以下操作：

df.file['New Column'] = df.file['Reference Area'] + df.file['Ratio']

来自课外。或者，您可以向类中添加一个方法来执行此操作：

def create_new_column(self):
    self.file['New Column'] = self.file['Reference Area'] + self.file['Ratio']

使用pandas，numpy从现有列创建列

1 个答案: