[AstroPy] How can I take the index of "True" value and minimum "True" in list with python ?

THƯỜNG Hoàng Đức hoangthuong.hust at gmail.com
Tue Apr 8 12:20:12 EDT 2014


thank you Trey,

How can i find the minimum value for different location in the list. Let me
show you more detail: (I am sorry, it is long )

I have:
In [15]: E
Out[15]:
array([  1.00000000e-03,   2.78255940e-03,   7.74263683e-03,
         2.15443469e-02,   5.99484250e-02,   1.66810054e-01,
         4.64158883e-01,   1.29154967e+00,   3.59381366e+00,
         1.00000000e+01])

In [16]: gE0
Out[16]:
array([[  1.00000000e-03,   1.00000000e-03,   1.00000000e-03,
          1.00000000e-03,   1.00000000e-03,   1.00000000e-03,
          1.00000000e-03,   1.00000000e-03,   1.00000000e-03,
          1.00000000e-03],
       [  5.99484250e-03,   5.99484250e-03,   5.99484250e-03,
          5.99484250e-03,   5.99484250e-03,   5.99484250e-03,
          5.99484250e-03,   5.99484250e-03,   5.99484250e-03,
          5.99484250e-03],
       [  3.59381366e-02,   3.59381366e-02,   3.59381366e-02,
          3.59381366e-02,   3.59381366e-02,   3.59381366e-02,
          3.59381366e-02,   3.59381366e-02,   3.59381366e-02,
          3.59381366e-02],
       [  2.15443469e-01,   2.15443469e-01,   2.15443469e-01,
          2.15443469e-01,   2.15443469e-01,   2.15443469e-01,
          2.15443469e-01,   2.15443469e-01,   2.15443469e-01,
          2.15443469e-01],
       [  1.29154967e+00,   1.29154967e+00,   1.29154967e+00,
          1.29154967e+00,   1.29154967e+00,   1.29154967e+00,
          1.29154967e+00,   1.29154967e+00,   1.29154967e+00,
          1.29154967e+00],
       [  1.18292276e+00,   1.20239338e+00,   1.26419499e+00,
          1.38016526e+00,   1.57688572e+00,   1.91417885e+00,
          2.55149610e+00,   4.10977947e+00,   7.74263683e+00,
          7.74263683e+00],
       [  2.77831168e-01,   2.82126806e-01,   2.95703802e-01,
          3.20921794e-01,   3.62928377e-01,   4.32761236e-01,
          5.56895376e-01,   8.15796501e-01,   1.61701932e+00,
          4.64158883e+01],
       [  7.88832931e-02,   8.01002871e-02,   8.39462486e-02,
          9.10876310e-02,   1.02977169e-01,   1.22725700e-01,
          1.57778342e-01,   2.30672383e-01,   4.54431889e-01,
          2.78255940e+02],
       [  4.46767553e-02,   4.53659668e-02,   4.75440123e-02,
          5.15882797e-02,   5.83213761e-02,   6.95047231e-02,
          8.93535809e-02,   1.30626292e-01,   2.57284143e-01,
          1.66810054e+03],
       [  4.84949885e-02,   4.92431017e-02,   5.16072881e-02,
          5.59971873e-02,   6.33057070e-02,   7.54447993e-02,
          9.69899542e-02,   1.41789797e-01,   2.79271195e-01,
          1.00000000e+04]])

In [25]: (abs(E - gE0) < 0.02)
Out[25]:
array([[ True,  True,  True, False, False, False, False, False, False,
        False],
       [ True,  True,  True,  True, False, False, False, False, False,
        False],
       [False, False, False,  True, False, False, False, False, False,
        False],
       [False, False, False, False, False, False, False, False, False,
        False],
       [False, False, False, False, False, False, False,  True, False,
        False],
       [False, False, False, False, False, False, False, False, False,
        False],
       [False, False, False, False, False, False, False, False, False,
        False],
       [False, False, False, False, False, False, False, False, False,
        False],
       [False, False, False, False,  True, False, False, False, False,
        False],
       [False, False, False, False,  True, False, False, False, False,
        False]], dtype=bool)

In [26]: abs(E - gE0)
Out[26]:
array([[  0.00000000e+00,   1.78255940e-03,   6.74263683e-03,
          2.05443469e-02,   5.89484250e-02,   1.65810054e-01,
          4.63158883e-01,   1.29054967e+00,   3.59281366e+00,
          9.99900000e+00],
       [  4.99484250e-03,   3.21228310e-03,   1.74779432e-03,
          1.55495044e-02,   5.39535825e-02,   1.60815211e-01,
          4.58164041e-01,   1.28555482e+00,   3.58781882e+00,
          9.99400516e+00],
       [  3.49381366e-02,   3.31555772e-02,   2.81954998e-02,
          1.43937897e-02,   2.40102884e-02,   1.30871917e-01,
          4.28220747e-01,   1.25561153e+00,   3.55787553e+00,
          9.96406186e+00],
       [  2.14443469e-01,   2.12660910e-01,   2.07700832e-01,
          1.93899122e-01,   1.55495044e-01,   4.86334153e-02,
          2.48715414e-01,   1.07610620e+00,   3.37837019e+00,
          9.78455653e+00],
       [  1.29054967e+00,   1.28876711e+00,   1.28380703e+00,
          1.27000532e+00,   1.23160124e+00,   1.12473961e+00,
          8.27390782e-01,   1.33226763e-15,   2.30226400e+00,
          8.70845033e+00],
       [  1.18192276e+00,   1.19961082e+00,   1.25645235e+00,
          1.35862091e+00,   1.51693729e+00,   1.74736880e+00,
          2.08733721e+00,   2.81822980e+00,   4.14882316e+00,
          2.25736317e+00],
       [  2.76831168e-01,   2.79344246e-01,   2.87961166e-01,
          2.99377447e-01,   3.02979952e-01,   2.65951182e-01,
          9.27364927e-02,   4.75753164e-01,   1.97679434e+00,
          3.64158883e+01],
       [  7.78832931e-02,   7.73177277e-02,   7.62036117e-02,
          6.95432841e-02,   4.30287441e-02,   4.40843535e-02,
          3.06380541e-01,   1.06087728e+00,   3.13938177e+00,
          2.68255940e+02],
       [  4.36767553e-02,   4.25834074e-02,   3.98013755e-02,
          3.00439328e-02,   1.62704897e-03,   9.73053306e-02,
          3.74805302e-01,   1.16092337e+00,   3.33652952e+00,
          1.65810054e+03],
       [  4.74949885e-02,   4.64605423e-02,   4.38646513e-02,
          3.44528404e-02,   3.35728195e-03,   9.13652544e-02,
          3.67168929e-01,   1.14975987e+00,   3.31454247e+00,
          9.99000000e+03]])

and Finaly:
At the first red line. I would to take the index[2] of value
1.78255940e-03(minimum)
At the second line. I would to take the index of value  1.74779432e-03
(minimum)
.
.
.

May you try to help me

Thuong,


2014-04-08 16:09 GMT+02:00 Trey Wenger <tvw2pu at virginia.edu>:

> Hi Thuong,
>
> I would do this
>
> index = abs(gE0[:,0] - ek).argmin()
>
> .argmin() returns the index at which the previous argument is smallest.
> Now, gE0[;,0][index] will be the value of gE0[;,0] closest to ek.
>
> For example,
>
> IPy> x = np.array([1.1, 2.3, 4.4])
> IPy> y = 2.2
> IPy> index = np.abs(x-y).argmin()
> IPy> index
> Out> 1
> IPy> x[index]
> Out> 2.3
> IPy> # this is the value in x closest to y
>
> Cheers,
> Trey
>
>
> On Tue, Apr 8, 2014 at 9:57 AM, THƯỜNG Hoàng Đức <
> hoangthuong.hust at gmail.com> wrote:
>
>> Dear AstroPyer,
>>
>> I have problem with ideals !
>> Firstly, I have two array. "ek" (one dimension - value in logspace) and
>> "gE0[]" (two dimension - value in logspace). After that I scan value ek in
>> array gE0 to find the equal value, It mean that abs(ek-gE0[:,0]) = 0. Due
>> to the numerical that in logspace, it can not equal zeros(There are some
>> point near the 0), and then I put the error for example err < 0.08 >>>>
>> abs(ek-gE0[:,0]) < 0.08. You can see the value below. The result I would to
>> take is True but it has several value < 0.08 also true, then how can i take
>> smallest if have several True.
>>
>>
>> In [53]: abs(ek-gE0[:,0]) < 0.08
>> Out[53]: array([False,  True, False, False, False, False,  True,  True,
>> True,  True], dtype=bool)
>>
>> ek = 0.1
>> In [52]: gE0[:,0]
>> Out[52]:
>> array([ 0.01      ,  0.04641589,  0.21544347,  1.        ,  1.93593016,
>>         0.51306049,  0.15479754,  0.06105322,  0.04410808,  0.04849499])
>>
>> How can i take only the value: i = 1, value = 0.04641589 and i = 9, value
>> = 0.04410808
>>
>>
>> Thankyou very muck
>>
>>  Merci beaucoup,
>>
>> Thuong
>>
>> ================================================
>> THUONG Hoang Duc
>>
>> Université des Sciences et des Technologies de Hanoi(USTH)
>> University of Science and Technology of Hanoi(USTH)
>> Hanoi University of Science and Technology (HUST)
>>
>> Email: hoangthuong.hust at gmail.com
>> Tel: +33 06 52 92 00 96
>> Tel: +84 01692887738
>>
>>
>> _______________________________________________
>> AstroPy mailing list
>> AstroPy at scipy.org
>> http://mail.scipy.org/mailman/listinfo/astropy
>>
>>
>
>
> --
> Trey V. Wenger
> Department of Astronomy
> University of Virginia
> http://www.astro.virginia.edu/~tvw2pu/
>



-- 

================================================
THUONG Hoang Duc

Université des Sciences et des Technologies de Hanoi(USTH)
University of Science and Technology of Hanoi(USTH)
Hanoi University of Science and Technology (HUST)

Email: hoangthuong.hust at gmail.com
Tel: +33 06 52 92 00 96
Tel: +84 01692887738
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