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+--- Thread: How do I map a list of values to specified colors? (/thread-22212.html)
How do I map a list of values to specified colors? - larkypython - Nov-04-2019
Here is what I want to do:
a list of 19 values:
[-1, 1, -2, 2, -3, 3, -4, 4, -5, 5, -6, 6, -7, 7, -8, 8, -9, 9, 0]
I would like the color grey gradual from white to black in the order in the list. How can I do that?
or else, if I can specify each different color to each different values, that is also ok.
Thanks.
RE: How do I map a list of values to specified colors? - Larz60+ - Nov-04-2019
what have you tried?
RE: How do I map a list of values to specified colors? - larkypython - Nov-05-2019
Thanks, Larz60+, What I am thinking about is mapping the list
[-1, 1, -2, 2, -3, 3, -4, 4, -5, 5, -6, 6, -7, 7, -8, 8, -9, 9, 0] to another list
[255//19*i for i in range(19)] first
and then use
plt.imshow(arr, cmap='gray', vmin=0, vmax=255//19*19)
plt.show()
to show the array
I felt this method is not direct. Is there any better method, I mean directly assign a color to that number in the original list.
Thank you very much!
RE: How do I map a list of values to specified colors? - MckJohan - Nov-05-2019
is this what you are looking for?
>>> import numpy as np
>>> delta = 0.025
>>> x = y = np.arange(-3.0, 3.0, delta)
>>> x
array([-3.0000000e+00, -2.9750000e+00, -2.9500000e+00, -2.9250000e+00,
-2.9000000e+00, -2.8750000e+00, -2.8500000e+00, -2.8250000e+00,
-2.8000000e+00, -2.7750000e+00, -2.7500000e+00, -2.7250000e+00,
-2.7000000e+00, -2.6750000e+00, -2.6500000e+00, -2.6250000e+00,
-2.6000000e+00, -2.5750000e+00, -2.5500000e+00, -2.5250000e+00,
-2.5000000e+00, -2.4750000e+00, -2.4500000e+00, -2.4250000e+00,
-2.4000000e+00, -2.3750000e+00, -2.3500000e+00, -2.3250000e+00,
-2.3000000e+00, -2.2750000e+00, -2.2500000e+00, -2.2250000e+00,
-2.2000000e+00, -2.1750000e+00, -2.1500000e+00, -2.1250000e+00,
-2.1000000e+00, -2.0750000e+00, -2.0500000e+00, -2.0250000e+00,
-2.0000000e+00, -1.9750000e+00, -1.9500000e+00, -1.9250000e+00,
-1.9000000e+00, -1.8750000e+00, -1.8500000e+00, -1.8250000e+00,
-1.8000000e+00, -1.7750000e+00, -1.7500000e+00, -1.7250000e+00,
-1.7000000e+00, -1.6750000e+00, -1.6500000e+00, -1.6250000e+00,
-1.6000000e+00, -1.5750000e+00, -1.5500000e+00, -1.5250000e+00,
-1.5000000e+00, -1.4750000e+00, -1.4500000e+00, -1.4250000e+00,
-1.4000000e+00, -1.3750000e+00, -1.3500000e+00, -1.3250000e+00,
-1.3000000e+00, -1.2750000e+00, -1.2500000e+00, -1.2250000e+00,
-1.2000000e+00, -1.1750000e+00, -1.1500000e+00, -1.1250000e+00,
-1.1000000e+00, -1.0750000e+00, -1.0500000e+00, -1.0250000e+00,
-1.0000000e+00, -9.7500000e-01, -9.5000000e-01, -9.2500000e-01,
-9.0000000e-01, -8.7500000e-01, -8.5000000e-01, -8.2500000e-01,
-8.0000000e-01, -7.7500000e-01, -7.5000000e-01, -7.2500000e-01,
-7.0000000e-01, -6.7500000e-01, -6.5000000e-01, -6.2500000e-01,
-6.0000000e-01, -5.7500000e-01, -5.5000000e-01, -5.2500000e-01,
-5.0000000e-01, -4.7500000e-01, -4.5000000e-01, -4.2500000e-01,
-4.0000000e-01, -3.7500000e-01, -3.5000000e-01, -3.2500000e-01,
-3.0000000e-01, -2.7500000e-01, -2.5000000e-01, -2.2500000e-01,
-2.0000000e-01, -1.7500000e-01, -1.5000000e-01, -1.2500000e-01,
-1.0000000e-01, -7.5000000e-02, -5.0000000e-02, -2.5000000e-02,
-1.0658141e-14, 2.5000000e-02, 5.0000000e-02, 7.5000000e-02,
1.0000000e-01, 1.2500000e-01, 1.5000000e-01, 1.7500000e-01,
2.0000000e-01, 2.2500000e-01, 2.5000000e-01, 2.7500000e-01,
3.0000000e-01, 3.2500000e-01, 3.5000000e-01, 3.7500000e-01,
4.0000000e-01, 4.2500000e-01, 4.5000000e-01, 4.7500000e-01,
5.0000000e-01, 5.2500000e-01, 5.5000000e-01, 5.7500000e-01,
6.0000000e-01, 6.2500000e-01, 6.5000000e-01, 6.7500000e-01,
7.0000000e-01, 7.2500000e-01, 7.5000000e-01, 7.7500000e-01,
8.0000000e-01, 8.2500000e-01, 8.5000000e-01, 8.7500000e-01,
9.0000000e-01, 9.2500000e-01, 9.5000000e-01, 9.7500000e-01,
1.0000000e+00, 1.0250000e+00, 1.0500000e+00, 1.0750000e+00,
1.1000000e+00, 1.1250000e+00, 1.1500000e+00, 1.1750000e+00,
1.2000000e+00, 1.2250000e+00, 1.2500000e+00, 1.2750000e+00,
1.3000000e+00, 1.3250000e+00, 1.3500000e+00, 1.3750000e+00,
1.4000000e+00, 1.4250000e+00, 1.4500000e+00, 1.4750000e+00,
1.5000000e+00, 1.5250000e+00, 1.5500000e+00, 1.5750000e+00,
1.6000000e+00, 1.6250000e+00, 1.6500000e+00, 1.6750000e+00,
1.7000000e+00, 1.7250000e+00, 1.7500000e+00, 1.7750000e+00,
1.8000000e+00, 1.8250000e+00, 1.8500000e+00, 1.8750000e+00,
1.9000000e+00, 1.9250000e+00, 1.9500000e+00, 1.9750000e+00,
2.0000000e+00, 2.0250000e+00, 2.0500000e+00, 2.0750000e+00,
2.1000000e+00, 2.1250000e+00, 2.1500000e+00, 2.1750000e+00,
2.2000000e+00, 2.2250000e+00, 2.2500000e+00, 2.2750000e+00,
2.3000000e+00, 2.3250000e+00, 2.3500000e+00, 2.3750000e+00,
2.4000000e+00, 2.4250000e+00, 2.4500000e+00, 2.4750000e+00,
2.5000000e+00, 2.5250000e+00, 2.5500000e+00, 2.5750000e+00,
2.6000000e+00, 2.6250000e+00, 2.6500000e+00, 2.6750000e+00,
2.7000000e+00, 2.7250000e+00, 2.7500000e+00, 2.7750000e+00,
2.8000000e+00, 2.8250000e+00, 2.8500000e+00, 2.8750000e+00,
2.9000000e+00, 2.9250000e+00, 2.9500000e+00, 2.9750000e+00])
RE: How do I map a list of values to specified colors? - larkypython - Nov-05-2019
Thanks MckJohan, but nope. What I want to do is to specify a certain value to a specified color, maybe through RGB values.
establish the connections like the following:
-1 ---------------> R200 G150 B0
1 ---------------> R....G....B...
...
Something like this, and then use the map to draw