data frame excel cell calulation

[buunaanaa]

Well, let me ask the question in another way.

def macdfuncs(data):
    
    # here are theclose=data['Close'] code for EMA short and EMA long
    close=data['Close']
    
    #EMA short
    sma_short = close.rolling(12).mean()
    temp1=close.copy()
    temp1.iloc[0:12] = sma_short[0:12]

    ema_short = temp1.ewm(span=12, adjust=False).mean()

This code is not efficient.

    sma_short = close.rolling(12).mean()
    temp1=close.copy()
    temp1.iloc[0:12] = sma_short[0:12]

I only need the 12th cell in "ema_short" column to be the average of the first 12 cells in "close" column . and 13th to end in "ema_short" to be EMA.
is there a way just set the specific cell to be the average of 12 cells?

Thanks.