Trying to append a float to a multi-dimensional list

Asked Jul 07 '22 at 08:00

Active Jul 08 '22 at 12:45

Viewed 44 times

I am trying to append a float number temp to the list pChange. However I get an error IndexError: list index out of range The code works fine, except when I try to append to the list in pChange[j].append(temp)

def loadPrices(fn):     #grabs prices from prices.txt
    global nt, nInst
    df = pd.read_csv(fn, sep='\s+', header=None, index_col=None)
    nt, nInst = df.values.shape
    return (df.values).T

pricesFile = "./prices.txt"
prcAll = loadPrices(pricesFile)     #data stored in prcAll


pChange = [[]]*20
j = 0
print(pChange[j])
for stock in prcAll:
    for i in range(1,5,1):
        temp = prcAll[j][i] / prcAll[j][i-1]
        pChange[j].append(temp)
        #print(j)
    j = j+1

edited Jul 08 '22 at 12:45

Lazyer

asked Jul 07 '22 at 08:00

Shotty

`pChange` will contain 20 references to the same list. Adding a item to the one list will add it to all references. – mousetail Jul 07 '22 at 08:02
1

Looks like `len(prcAll) > 20` which leads the the index that is greater or equal to 20 and leads to a `indexError` – mousetail Jul 07 '22 at 08:03
If there are more values in `prcAll` than `pChange` you will get this error – Nick Jul 07 '22 at 08:03
2

Heads up, once this error is fixed the next thing you'll be asking about is [this](https://stackoverflow.com/questions/240178/list-of-lists-changes-reflected-across-sublists-unexpectedly). – timgeb Jul 07 '22 at 08:05
i changed the range to 251, which = prcAll, and: IndexError: index 250 is out of bounds for axis 0 with size 250 – Shotty Jul 07 '22 at 08:20
@Shotty You won't get that error with the code shown in your question. What/where is *prcAll* ? – DarkKnight Jul 07 '22 at 08:24
Just updated the code provided – Shotty Jul 07 '22 at 08:28
Can you post the content of `prices.txt` file? – Ramon Moraes Jul 08 '22 at 12:52

Trying to append a float to a multi-dimensional list

0 Answers0