3

I have some quarter level data for finance deals, so a pretty big dataset. I now want to add the following values to a new column repeated over and over:

[-12,-11,-10,-9,-8,-7,-6,-5,-4,-3,-2,-1,0,1,2,3,4,5,6,7,8,9,10,11,12]

The column should then look something like this:

A
-12
-11
-10
...
11
12
-12
-11
...
11
12

So basically just that list repeating over and over until the last row of my Dataframe. I hope this question is clear enough.

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3 Answers 3

Reset to default
3

Try this:

N = len(df)
df['A'] = pd.Series(np.tile(lst, N//len(lst))).iloc[:N]
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2 Comments

It doesn't seem to be working, the values aren't repeating as I want them to. They are all jumbled up and seem to follow no particular pattern. I also get this message: A value is trying to be set on a copy of a slice from a DataFrame. Try using .loc[row_indexer,col_indexer] = value instead See the caveats in the documentation: pandas.pydata.org/pandas-docs/stable/…
Nevermind, your solution worked. I forgot to reindex my dataframe thats is why the numbers werent repeating as I wanted them to. Thanks for your answer
2

itertools.cycle will repeat an iterator indefinitely, and itertools.islice takes only the leading portion.

pd.Series(list(itertools.islice(itertools.cycle(range(-12,13)), len(df))))
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2

Using numpy place

a=np.zeros(len(data_file))
np.place(a,a>=0,np.array([1,2]))
a
Out[526]: array([1., 2., 1., 2.])
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