multi-numpy array from dataframe

Question

I have 5 Pandas DataFrames, its 5 classes of objects in 80,00 images and the coordinates of the objects. Basically, there is more than one class in each image

class 1:

 image_id    x      y
 image_0    4835    106
 image_0    2609    309
 image_0    2891    412
 image_0    1823    431
 image_0    3309    449

and ends with:

image_945    950    1238
image_945    34     1362
image_945    821    2059
image_945    1448   2896

class 2:

image_id     x      y
image_0     4835    106
image_0     2609    309
image_0     2891    412
image_0     1823    431
image_0     3309    449

ends with:

image_945    9530   128
image_945    354    162
image_945    8321   259
image_945    1448   2596

What I'm trying to do is get the x and y to be in the same array while the image_id does not repeat. like so:

             class 1               class 2         class n
image_0    [(4240, 41),          [(3231, 1086),     
            (3833, 74),           (2576, 1372),
            (4470, 94),           (3487, 1462),
            (2946, 10)]           (48...)]

image_1     [(4835, 106),        [(4532,5438),
             (2609, 309),         (4322,777),
             (2891, 412),         (665,899),
             (1823,...)]          (54..,..)]

image_n     [(...),              [(...),
             (...)]               (...)]

Basically converting into a multidimensional numpy array. Of course, I've looked before posting.

piRSquared · Accepted Answer · 2017-04-18 07:53:41Z

1

Create a dictionary of dataframes to pass to pd.concat

clss = {'class 1': cls1, 'class 2': cls2}
catted = pd.concat(clss)

g = catted.groupby(['image_id', pd.Grouper(level=0)])[['x', 'y']]
g.apply(lambda x: list(zip(*x.values.T))).unstack()

answered Apr 18, 2017 at 7:53

piRSquared

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4 Comments

piRSquared Over a year ago

@LiamLarsen don't forget to up vote at accept if this answered your question.

Liam Larsen Over a year ago

because I have less than 175 rep. my upvotes aren't counted. Kinda sad that I have over 100 upvotes and their all not even counted

piRSquared Over a year ago

@LiamLarsen of course they are. Your up votes start counting at 15

Liam Larsen Over a year ago

You are an absolute f***** LIFESAVER!! This worked PERFECTLY after searching for 2 days!!!!

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