如何读取 csv 文件中下一行的信息以执行资产增长计算

Question

comp = pd.read_csv('C:/Users/naitm/Desktop/python coding/FFM5/Question 1-1/5_factor_merge.csv')
# Create book equity --> Book value of equity cannot be negative
comp['be'] = comp['seq'] + comp['txditc'] - comp['ps']
comp['be'] = np.where(comp['be'] > 0, comp['be'], np.nan)

# Create operating profitability = total revenue - cost of goods sold - sell expense - admin expense 
#/ book equity
comp['op'] = (comp['revt'] - comp['cogs'] - comp['xsga'] - comp['xint']) / comp['be']

这些有效，因为所有单元格信息都在同一行中。但是我需要计算资产增长，它在同一当前行，但在同一家公司的下一行。如何访问下一行或上一行的那个？该字段是 'at' 所以我需要： comp['ag'] = (comp['at']-comp['at'])/comp['at'] #第一个是下一行，第二个是当前行，第三个是下一行

Answer 1

我知道这不是答案，只是为了帮助您说明 shift() 的工作原理。

import pandas as pd
df = pd.DataFrame({'A':[1,2,3,4,5]})
df['B'] = df.A.shift(1)
df['C'] = df.A.shift(-1)

print (df)

   A    B    C
0  1  NaN  2.0   # <--- value of B is NaN as shift of prev row is NaN
1  2  1.0  3.0
2  3  2.0  4.0
3  4  3.0  5.0
4  5  4.0  NaN   # <--- value of C is NaN as shift of next row is NaN

如何读取 csv 文件中下一行的信息以执行资产增长计算

How to Read information on the next line in csv file to perform calculation of Asset Growth

csv

dataframe

calculation