/ Python And R Data science skills: 36 reshape array and slicing array

Sunday 4 February 2018

36 reshape array and slicing array

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]])

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