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NoahVerner
Asked: 2022-08-09 00:32:22 +0800 CST 2022-08-09 00:32:22 +0800 CST

How to properly iterate a pandas column using a range of values ​​in Python?

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I happen to have the following information stored in a variable calleddf_trading_pair

           Start Date  Open Price  High Price   Low Price  Close Price         Volume                End Date
0 2022-08-08 07:15:00  0.00001241  0.00001242  0.00001238   0.00001239  16808259334.0 2022-08-08 07:19:59.999
1 2022-08-08 07:20:00  0.00001238  0.00001239  0.00001235   0.00001238   7237826684.0 2022-08-08 07:24:59.999
2 2022-08-08 07:25:00  0.00001238  0.00001239  0.00001237   0.00001238   1768234135.0 2022-08-08 07:29:59.999
3 2022-08-08 07:30:00  0.00001238  0.00001239  0.00001236   0.00001236   5243964161.0 2022-08-08 07:34:59.999
4 2022-08-08 07:35:00  0.00001236  0.00001237  0.00001235   0.00001235   8802029320.0 2022-08-08 07:39:59.999
5 2022-08-08 07:40:00  0.00001234  0.00001236  0.00001233   0.00001234   3038529151.0 2022-08-08 07:44:59.999
6 2022-08-08 07:45:00  0.00001233  0.00001236  0.00001232   0.00001235   7700037899.0 2022-08-08 07:49:59.999
7 2022-08-08 07:50:00  0.00001235  0.00001237  0.00001235   0.00001237   1929229917.0 2022-08-08 07:54:59.999

I am interested in iterating over the column Open Priceusing a range of 4 values, in such a way that it prints the following information on each iteration:

iteration 1

0    0.00001241
1    0.00001238
2    0.00001238
3    0.00001238
Name: Open Price, dtype: float64

iteration 2

1    0.00001238
2    0.00001238
3    0.00001238
4    0.00001236
Name: Open Price, dtype: float64

. . .

iteration 5

4    0.00001236
5    0.00001234
6    0.00001233
7    0.00001235
Name: Open Price, dtype: float64

As such, I already have part of the solution and it is as follows:

for i in range(0, len(df_trading_pair)):
    slc = df_trading_pair["Open Price"].iloc[i : i + 4]
    print(slc)
    i = i + 1
    print("")

However , there is a problem, and that is that my solution iterates 3 times too many , printing the following after the 5th iteration:

iteration 6

5    0.00001234
6    0.00001233
7    0.00001235
Name: Open Price, dtype: float64

Iteration 7

6    0.00001233
7    0.00001235
Name: Open Price, dtype: float64

Iteration 8

7    0.00001235
Name: Open Price, dtype: float64

I would like to know how I can correct it, and if possible, an explanation of why my solution did not work as expected?

python-3.x

1 Answers

  1. Best Answer

    Good day,

    If you print len(df_trading_pair)you will see that it returns 8, since you dataframehave 8 rows and that is why it prints 8 times, but you need it to print 5 so it would have to subtract 3

    for i in range(0, len(df_trading_pair)-3):
    slc = df_trading_pair["Open Price"].iloc[i : i + 4]
    print(slc)
    i = i + 1
    print("")

    If you plan to create groups of variable size you could do the following formula

    grupo = 4
limite = len(df_trading_pair)-(grupo-1)

for i in range(0, limite):
    slc = df_trading_pair["Open Price"].iloc[i : i + grupo]
    print(slc)
    i = i + 1
    print("")

    And that way if you print for example in groups of 3, it will print 6 groups of 3.

    Example with groups of 3 elements returns:

    0    0.000012
1    0.000012
2    0.000012
Name: Open Price, dtype: float64

1    0.000012
2    0.000012
3    0.000012
Name: Open Price, dtype: float64

2    0.000012
3    0.000012
4    0.000012
Name: Open Price, dtype: float64

3    0.000012
4    0.000012
5    0.000012
Name: Open Price, dtype: float64

4    0.000012
5    0.000012
6    0.000012
Name: Open Price, dtype: float64

5    0.000012
6    0.000012
7    0.000012
Name: Open Price, dtype: float64
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