Compute balance column python dataframe with initial static value-CodePudding

i am trying to get a balance column in a python dataframe with an initial static value.

The logic:

start balance = 1000

current balance = previous current balance*(1 df['return'])

My attempt:

df.at[1,'current balance'] = 1000
df['current balance'] = df['current balance'].shift(1)*(1 df['return])

I can't get this output

Output dataframe:

return  current balance
0.01    1010.00
0.03    1040.30
0.045   1087.11

CodePudding user response：

Standard compound return:

initial_balance = 1000
df['current balance'] = (1   df['return']).cumprod() * initial_balance

>>> df
   return  current balance
0   0.010        1010.0000
1   0.030        1040.3000
2   0.045        1087.1135

CodePudding user response：

I would approach this by getting my df columns ready in lists and then add those rather than changing values in the df itself.

There's probably a more elegant solution but this should work:

df_return = [0.00, 0.01, 0.03, 0.045]
df_current_balance = [1000]
# Calculate the current value for each return value
for x in range(1, len(df_return)):
    df_current_balance.append(df_current_balance[x - 1] * (1   df_return[x]))

output = {"return": df_return[1:], "current balance": df_current_balance[1:]}

df = pd.DataFrame(output)