25 ds python Matrix creation

In [1]:

import numpy as np

In [3]:

a=[1,2,3]
b=["ram","sur","nai"]
c=["hi","plz","subcribe"]

In [4]:

a

Out[4]:

[1, 2, 3]

In [5]:

b

Out[5]:

['ram', 'sur', 'nai']

In [6]:

c

Out[6]:

['hi', 'plz', 'subcribe']

In [9]:

z=np.array([a,b,c])

In [10]:

z

Out[10]:

array([['1', '2', '3'],
       ['ram', 'sur', 'nai'],
       ['hi', 'plz', 'subcribe']],
      dtype='<U11')

In [11]:

print(z)

[['1' '2' '3']
 ['ram' 'sur' 'nai']
 ['hi' 'plz' 'subcribe']]

In [12]:

z[2,1]

Out[12]:

'plz'

In [13]:

mat1=np.array([a,b,c])

In [14]:

mat1

Out[14]:

array([['1', '2', '3'],
       ['ram', 'sur', 'nai'],
       ['hi', 'plz', 'subcribe']],
      dtype='<U11')

In [15]:

print(mat1)

[['1' '2' '3']
 ['ram' 'sur' 'nai']
 ['hi' 'plz' 'subcribe']]

In [16]:

mat1[1,1]

Out[16]:

'sur'

In [17]:

mat1[2,1]

Out[17]:

'plz'

In [18]:

mat1[1,2]

Out[18]:

'nai'

In [24]:

arra1=np.arange(1,21)

In [25]:

arra1

Out[25]:

array([ 1,  2,  3,  4,  5,  6,  7,  8,  9, 10, 11, 12, 13, 14, 15, 16, 17,
       18, 19, 20])

np.

In [27]:

mat2=np.reshape(arra1,(4,5) )

In [28]:

mat2

Out[28]:

array([[ 1,  2,  3,  4,  5],
       [ 6,  7,  8,  9, 10],
       [11, 12, 13, 14, 15],
       [16, 17, 18, 19, 20]])

In [29]:

mat3=np.reshape(arra1,(4,5),order="F")

In [30]:

mat3

Out[30]:

array([[ 1,  5,  9, 13, 17],
       [ 2,  6, 10, 14, 18],
       [ 3,  7, 11, 15, 19],
       [ 4,  8, 12, 16, 20]])

In [31]:

mat3[0,0]

Out[31]:

1

In [37]:

arra1.reshape(5,4,order="C")

Out[37]:

array([[ 1,  2,  3,  4],
       [ 5,  6,  7,  8],
       [ 9, 10, 11, 12],
       [13, 14, 15, 16],
       [17, 18, 19, 20]])

In [38]:

mat3.min()

Out[38]:

1

In [39]:

mat1.min()

---------------------------------------------------------------------------
TypeError                                 Traceback (most recent call last)
<ipython-input-39-858a02ee684c> in <module>()
----> 1 mat1.min()

~\Anaconda3\lib\site-packages\numpy\core\_methods.py in _amin(a, axis, out, keepdims)
     27 
     28 def _amin(a, axis=None, out=None, keepdims=False):
---> 29     return umr_minimum(a, axis, None, out, keepdims)
     30 
     31 def _sum(a, axis=None, dtype=None, out=None, keepdims=False):

TypeError: cannot perform reduce with flexible type

In [40]:

mat1

Out[40]:

array([['1', '2', '3'],
       ['ram', 'sur', 'nai'],
       ['hi', 'plz', 'subcribe']],
      dtype='<U11')