*In[1]:*
#Numpy Arrays*In[2]:*
my_list = [1,23,34]*In[3]:*
import numpy as np
arr= np.array(my_list)*In[4]:*
arr*Out[4]:* ----array([ 1, 23, 34])----
*In[5]:*
my_mat=[[1,2,3],[4,5,6],[7,8,9]]*In[6]:*
my_mat*Out[6]:* ----[[1, 2, 3], [4, 5, 6], [7, 8, 9]]----
*In[7]:*
np.array(my_mat)*Out[7]:* ----array([[1, 2, 3], [4, 5, 6], [7, 8, 9]])----
*In[8]:*
my_mat*Out[8]:* ----[[1, 2, 3], [4, 5, 6], [7, 8, 9]]----
*In[9]:*
np.arange(0,10)*Out[9]:* ----array([0, 1, 2, 3, 4, 5, 6, 7, 8, 9])----
*In[10]:*
np.arange(0,11,2)*Out[10]:* ----array([ 0, 2, 4, 6, 8, 10])----
*In[11]:*
np.zeros(3)*Out[11]:* ----array([0., 0., 0.])----
*In[12]:*
np.zeros((5,6))*Out[12]:* ----array([[0., 0., 0., 0., 0., 0.], [0., 0., 0., 0., 0., 0.], [0., 0., 0., 0., 0., 0.], [0., 0., 0., 0., 0., 0.], [0., 0., 0., 0., 0., 0.]])----
*In[13]:*
np.ones(4)*Out[13]:* ----array([1., 1., 1., 1.])----
*In[15]:*
np.ones((4,5))*Out[15]:* ----array([[1., 1., 1., 1., 1.], [1., 1., 1., 1., 1.], [1., 1., 1., 1., 1.], [1., 1., 1., 1., 1.]])----
*In[16]:*
np.linspace(0,5,10) #equally spaced point ID Array*Out[16]:* ----array([0. , 0.55555556, 1.11111111, 1.66666667, 2.22222222, 2.77777778, 3.33333333, 3.88888889, 4.44444444, 5. ])----
*In[17]:*
np.linspace(0,10,100)*Out[17]:* ----array([ 0. , 0.1010101 , 0.2020202 , 0.3030303 , 0.4040404 , 0.50505051, 0.60606061, 0.70707071, 0.80808081, 0.90909091, 1.01010101, 1.11111111, 1.21212121, 1.31313131, 1.41414141, 1.51515152, 1.61616162, 1.71717172, 1.81818182, 1.91919192, 2.02020202, 2.12121212, 2.22222222, 2.32323232, 2.42424242, 2.52525253, 2.62626263, 2.72727273, 2.82828283, 2.92929293, 3.03030303, 3.13131313, 3.23232323, 3.33333333, 3.43434343, 3.53535354, 3.63636364, 3.73737374, 3.83838384, 3.93939394, 4.04040404, 4.14141414, 4.24242424, 4.34343434, 4.44444444, 4.54545455, 4.64646465, 4.74747475, 4.84848485, 4.94949495, 5.05050505, 5.15151515, 5.25252525, 5.35353535, 5.45454545, 5.55555556, 5.65656566, 5.75757576, 5.85858586, 5.95959596, 6.06060606, 6.16161616, 6.26262626, 6.36363636, 6.46464646, 6.56565657, 6.66666667, 6.76767677, 6.86868687, 6.96969697, 7.07070707, 7.17171717, 7.27272727, 7.37373737, 7.47474747, 7.57575758, 7.67676768, 7.77777778, 7.87878788, 7.97979798, 8.08080808, 8.18181818, 8.28282828, 8.38383838, 8.48484848, 8.58585859, 8.68686869, 8.78787879, 8.88888889, 8.98989899, 9.09090909, 9.19191919, 9.29292929, 9.39393939, 9.49494949, 9.5959596 , 9.6969697 , 9.7979798 , 9.8989899 , 10. ])----
*In[18]:*
np.eye(4) #Identity Matrix*Out[18]:* ----array([[1., 0., 0., 0.], [0., 1., 0., 0.], [0., 0., 1., 0.], [0., 0., 0., 1.]])----
*In[19]:*
np.random.rand(5)*Out[19]:* ----array([0.97506746, 0.38690978, 0.72881108, 0.61062336, 0.5265079 ])----
*In[20]:*
np.random.rand(5,5)*Out[20]:* ----array([[0.5324989 , 0.77071971, 0.24628283, 0.67430309, 0.62663696], [0.66372165, 0.88842542, 0.41154438, 0.60927341, 0.65917661], [0.95416511, 0.41111324, 0.61263116, 0.92069949, 0.34697438], [0.75645627, 0.84816866, 0.71212879, 0.7903755 , 0.02825628], [0.71480107, 0.47966006, 0.99891823, 0.51963936, 0.06420895]])----
*In[21]:*
np.random.randn(3) #standard normal distribution*Out[21]:* ----array([-1.21969646, 0.12520287, 1.1180009 ])----
*In[22]:*
np.random.randint(1,100)*Out[22]:* ----78----
*In[23]:*
np.random.randint(1,100,10)*Out[23]:* ----array([63, 1, 86, 33, 10, 18, 55, 57, 78, 73])----
*In[24]:*
arr=np.arange(25)*In[25]:*
arr*Out[25]:* ----array([ 0, 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17, 18, 19, 20, 21, 22, 23, 24])----
*In[26]:*
ranarr=np.random.randint(0,50,10)*In[27]:*
ranarr*Out[27]:* ----array([47, 22, 38, 24, 21, 17, 44, 27, 41, 15])----
*In[28]:*
arr.reshape(5,5) # converting 1d to 2d array*Out[28]:* ----array([[ 0, 1, 2, 3, 4], [ 5, 6, 7, 8, 9], [10, 11, 12, 13, 14], [15, 16, 17, 18, 19], [20, 21, 22, 23, 24]])----
*In[30]:*
ranarr.max()*Out[30]:* ----47----
*In[31]:*
ranarr.min()*Out[31]:* ----15----
*In[32]:*
ranarr.argmax() #index of maximum value*Out[32]:* ----0----
*In[33]:*
ranarr.argmin()#index of minimum value*Out[33]:* ----9----
*In[34]:*
arr.shape # return shape of current array*Out[34]:* ----(25,)----
*In[35]:*
arr1=arr.reshape(5,5)*In[36]:*
arr1*Out[36]:* ----array([[ 0, 1, 2, 3, 4], [ 5, 6, 7, 8, 9], [10, 11, 12, 13, 14], [15, 16, 17, 18, 19], [20, 21, 22, 23, 24]])----
*In[37]:*
arr1.shape*Out[37]:* ----(5, 5)----
*In[38]:*
arr.dtype*Out[38]:* ----dtype('int64')----
*In[39]:*
from numpy.random import randint
randint(2,10)*Out[39]:* ----6----
*In[40]:*
# Numpy Indexing & Selection*In[41]:*
arr[8]*Out[41]:* ----8----
*In[42]:*
arr[1:5]*Out[42]:* ----array([1, 2, 3, 4])----
*In[43]:*
arr[0:]*Out[43]:* ----array([ 0, 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17, 18, 19, 20, 21, 22, 23, 24])----
*In[44]:*
arr[:8]*Out[44]:* ----array([0, 1, 2, 3, 4, 5, 6, 7])----
*In[45]:*
arr[0:6]*Out[45]:* ----array([0, 1, 2, 3, 4, 5])----
*In[46]:*
arr[0:5]=100*In[47]:*
arr*Out[47]:* ----array([100, 100, 100, 100, 100, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17, 18, 19, 20, 21, 22, 23, 24])----
*In[48]:*
arr2=arr[0:8]*In[49]:*
arr2*Out[49]:* ----array([100, 100, 100, 100, 100, 5, 6, 7])----
*In[50]:*
arr2[:]=99*In[51]:*
arr2*Out[51]:* ----array([99, 99, 99, 99, 99, 99, 99, 99])----
*In[52]:*
arr_copy=arr[0:6]*In[53]:*
arr_copy*Out[53]:* ----array([99, 99, 99, 99, 99, 99])----
*In[54]:*
arr_copy=arr.copy()*In[55]:*
arr_copy*Out[55]:* ----array([99, 99, 99, 99, 99, 99, 99, 99, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17, 18, 19, 20, 21, 22, 23, 24])----
*In[56]:*
arr_2d=np.array([[5,10,15],[20,25,30],[40,45,50]])*In[57]:*
arr_2d*Out[57]:* ----array([[ 5, 10, 15], [20, 25, 30], [40, 45, 50]])----
*In[58]:*
arr_2d[0]*Out[58]:* ----array([ 5, 10, 15])----
*In[59]:*
arr_2d[0][2]*Out[59]:* ----15----
*In[60]:*
arr_2d[2][1]*Out[60]:* ----45----
*In[61]:*
arr_2d[2,1]*Out[61]:* ----45----
*In[63]:*
arr_2d[:2,1:]*Out[63]:* ----array([[10, 15], [25, 30]])----
*In[64]:*
arr*Out[64]:* ----array([99, 99, 99, 99, 99, 99, 99, 99, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17, 18, 19, 20, 21, 22, 23, 24])----
*In[65]:*
arr >20*Out[65]:* ----array([ True, True, True, True, True, True, True, True, False, False, False, False, False, False, False, False, False, False, False, False, False, True, True, True, True])----
*In[66]:*
bool_arr=arr>20*In[67]:*
arr[bool_arr]*Out[67]:* ----array([99, 99, 99, 99, 99, 99, 99, 99, 21, 22, 23, 24])----
*In[68]:*
arr[arr>23]*Out[68]:* ----array([99, 99, 99, 99, 99, 99, 99, 99, 24])----
*In[69]:*
arr[arr<10]*Out[69]:* ----array([8, 9])----
*In[75]:*
arr1_2d=np.arange(50).reshape(5,10)*In[76]:*
arr1_2d*Out[76]:* ----array([[ 0, 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]])----
*In[77]:*
arr1_2d[1:3]*Out[77]:* ----array([[10, 11, 12, 13, 14, 15, 16, 17, 18, 19], [20, 21, 22, 23, 24, 25, 26, 27, 28, 29]])----
*In[78]:*
arr1_2d[1:3,3:5]*Out[78]:* ----array([[13, 14], [23, 24]])----
*In[ ]:*