36 reshape array and slicing array

In [2]:

import numpy as np
m1=np.arange(1,51).reshape(5,10)

In [3]:

m1

Out[3]:

array([[ 1,  2,  3,  4,  5,  6,  7,  8,  9, 10],
       [11, 12, 13, 14, 15, 16, 17, 18, 19, 20],
       [21, 22, 23, 24, 25, 26, 27, 28, 29, 30],
       [31, 32, 33, 34, 35, 36, 37, 38, 39, 40],
       [41, 42, 43, 44, 45, 46, 47, 48, 49, 50]])

In [13]:

m1[2:,:3]

Out[13]:

array([[21, 22, 23],
       [31, 32, 33],
       [41, 42, 43]])

In [19]:

m1[0:3,0:3
  ]

Out[19]:

array([[ 1,  2,  3],
       [11, 12, 13],
       [21, 22, 23]])

In [3]:

m1[1,1]

Out[3]:

12

In [4]:

m1

Out[4]:

array([[ 1,  2,  3,  4,  5,  6,  7,  8,  9, 10],
       [11, 12, 13, 14, 15, 16, 17, 18, 19, 20],
       [21, 22, 23, 24, 25, 26, 27, 28, 29, 30],
       [31, 32, 33, 34, 35, 36, 37, 38, 39, 40],
       [41, 42, 43, 44, 45, 46, 47, 48, 49, 50]])

In [5]:

m1[1][1]

Out[5]:

12

In [6]:

m1[1,1]

Out[6]:

12

In [7]:

m1[1]

Out[7]:

array([11, 12, 13, 14, 15, 16, 17, 18, 19, 20])

In [10]:

m1[:,0]

Out[10]:

array([ 1, 11, 21, 31, 41])

In [11]:

m1[:]

Out[11]:

array([[ 1,  2,  3,  4,  5,  6,  7,  8,  9, 10],
       [11, 12, 13, 14, 15, 16, 17, 18, 19, 20],
       [21, 22, 23, 24, 25, 26, 27, 28, 29, 30],
       [31, 32, 33, 34, 35, 36, 37, 38, 39, 40],
       [41, 42, 43, 44, 45, 46, 47, 48, 49, 50]])

In [13]:

m1[0:3]

Out[13]:

array([[ 1,  2,  3,  4,  5,  6,  7,  8,  9, 10],
       [11, 12, 13, 14, 15, 16, 17, 18, 19, 20],
       [21, 22, 23, 24, 25, 26, 27, 28, 29, 30]])

In [14]:

m1[:,0:3]

Out[14]:

array([[ 1,  2,  3],
       [11, 12, 13],
       [21, 22, 23],
       [31, 32, 33],
       [41, 42, 43]])

In [17]:

m1[1:2,0:3]

Out[17]:

array([[11, 12, 13]])

In [18]:

m1[2:4,4:7]

Out[18]:

array([[25, 26, 27],
       [35, 36, 37]])