Nerija .Alcin - 3 years ago 255
Python Question

How to do a loop selecting only the first values of an array?

Here's my code

``````    import numpy as np
contrainte1= 1080*0.65 # minutes tous les jours
contrainte2= 720*0.55 # minutes du lundi au vendredi
X=np.array([[9, 48],[12,    46],[14,    41],[12,    45],[6, 50],[10,    48],[25,    12],[26,    15],[30,    10],[31,    16],[40,    10],[41,    12],[35,    18],[35,    19],[30,    21],[28,    21],[25,    24],[21,    28],[22,    30],[25,    26],[26,    25],[30,    20],[32,    16],[35,    12]])<
#La première position représente la contrainte 1
#La deuxième position représente la contraire 2

# contrainte 1
for i in X[-19:]:
print(i)
for y in #This is where I need help
``````

I want to do a loop for each array(i) where I will do the sum of every value in the first section of my array. Per example I want to be able to do the sum of 9+12+14....+35 with np.sum()

When I try indexing like SciPy showed me I can't seem to find the technique to do what I want. Or I just dont understand(language barrier)

Thanks

If I understood you, you just want to sum elements in the first column? All that needs is a little indexing and `sum`:
``````In [19]: X[:, 0].sum()