Is it possible without using parallelization (Swifter, Parallel) to make an instant calculation imme-CodePudding

Is it possible without using parallelization (Swifter, Parallel) to make an instant calculation immediately without passing through the index, for example through the use of the "apply"-function for all dataset?

%%time
import random
df = pd.DataFrame({'A':random.sample(range(200), 200)})

for j in range(200):
    for i in df.index:
        df.loc[i,'A_last_{}'.format(j)] = df.loc[(df.index < i) & (df.index >= i - j),'A'].mean()

CodePudding user response：

%%time
import random
df = pd.DataFrame({'A':random.sample(range(200), 200)})

First calculate the sums.

df[1] = df['A'].shift()
for j in range(2, 200):
    df[j] = df[j-1].fillna(0)   df['A'].shift(j)

Then do the division for means and take care of the formatting

df = df.set_index('A')
df.divide(df.columns, axis=1)\
    .fillna(method='ffill', axis=1)\
    .rename(lambda x: f'A_last_{x}', axis=1)\
    .reset_index()