In [1]:
print 'hello world'
In [2]:
jark1=365
jark2=366
In [3]:
print jark1
print jark2
In [4]:
print type(jark1)
In [5]:
jark = int('test')
print jark
In [6]:
jark = [1,2,3,4,5]
for i in jark:
print jark
In [19]:
for i in jark:
print i
In [20]:
for i in jark:
print i
print '123'
In [10]:
jark =['test1','test2']
for i in range(0,len(jark)):
print jark[i]
In [17]:
fruits = ['banana', 'apple', 'mango']
for fruit in fruits: # 第二个实例
print '当前水果 :', fruit
In [18]:
for fruit in fruits: # 第二个实例
print '当前水果 :', fruit
In [54]:
import numpy
world_alcohol = numpy.genfromtxt('world_alcohol.txt',delimiter=',',skip_header=1)
print type(world_alcohol)
#print world_alcohol
is_value_empty = numpy.isnan(world_alcohol[:,4])
#print is_value_empty
world_alcohol[is_value_empty,4] = '0'
#a = world_alcohol[:,4].astype(float)
#a = a.astype(float)
total_alcohol = world_alcohol[:,4].astype(float).sum()
avg_alcohol = world_alcohol[:,4].astype(float).mean()
print total_alcohol
print avg_alcohol
In [22]:
print world_alcohol
In [45]:
vector = numpy.array([5,10,15,20])
matrix = numpy.array([[5,10,15],[20,25,30],[35,40,45]])
print vector
print matrix
print matrix[:,1]
print matrix[:,0:3]
print
print matrix[1:2,2:3]
#matrix == 30
#b = (vector == 10)
#print b
#print vector[b]
#c = (matrix[:,1]==25)
#print c
#print matrix[:,c]
#print vector.mean()
#print matrix.mean()
#print help(numpy.sum)
print matrix.sum(axis=1)
In [24]:
print vector.shape
print matrix.shape
In [25]:
vector.dtype
Out[25]:
In [26]:
matrix.dtype
Out[26]:
In [64]:
import numpy as np
print np.arange(15)
a = np.arange(15).reshape(3,5)
a
Out[64]:
In [65]:
a.shape
Out[65]:
In [66]:
a.ndim
Out[66]:
In [67]:
a.dtype.name
Out[67]:
In [68]:
a.size
Out[68]:
In [77]:
np.zeros((3,4),dtype=np.int32)
Out[77]:
In [76]:
np.ones((2,3,4),dtype=np.int32)
Out[76]:
In [80]:
np.arange(10,40,1)
Out[80]:
In [81]:
np.arange(14).reshape(2,7)
Out[81]:
In [87]:
np.random.random((2,3))*2-1
Out[87]:
In [90]:
from numpy import pi
np.linspace(2,2*pi,100)
Out[90]:
In [91]:
np.sin(np.linspace(2,2*pi,100))
Out[91]:
In [2]:
import numpy as np
B = np.arange(3)
print B
print np.exp(B)
print np.sqrt(B)
In [9]:
a = np.floor(10*np.random.random((3,4)))
print a
print '--------'
print a.ravel()
print '--------'
#a.shape = (6,2)
a.reshape(6,-1)
print a
print '--------'
print a.T
In [12]:
a = np.floor(10*np.random.random((2,2)))
b = np.floor(10*np.random.random((2,2)))
print a
print '-----'
print b
print '-----'
print np.hstack((a,b))
print np.vstack((a,b))
In [19]:
a = np.floor(10*np.random.random((2,12)))
print a
print '-----'
print np.hsplit(a,3)
print '-----'
print np.hsplit(a,(3,7))
print '-----'
a = np.floor(10*np.random.random((12,2)))
print a
print '-----'
#np.vsplit(a,3)
print np.vsplit(a,3)
In [21]:
a = np.arange(12)
b = a
print a,b
print b is a
b.shape = 3,4
print a.shape
print id(a)
print id(b)
In [45]:
c = a.view()
print c is a
#c.reshape(6,2)
c.shape = (2,6)
print c.shape
print a
print c
c[0,0]=9999
print a
print c
print id(a)
print id(c)
In [ ]:
d = a.copy()
print d is a
d[0,0] =9999
print d
print a
print id(a)
print id(d)
In [47]:
data = np.sin(np.arange(20)).reshape(5,4)
print data
print data.reshape(4,5)
print data.shape
#reshape cann't change this arange
In [72]:
print data
ind = data.argmax(axis=1)
print ind
#data_max = data[ind,range(data.shape[0])]
#print data_max
print data.shape[0]
#print range(data.shape[1])
#print data[ind,range(data.shape[1])]
print data[range(data.shape[0]),ind]
In [75]:
print data
index = data.argmax(axis=0)
print index
print range(data.shape[1])
print data[index,range(data.shape[1])]
In [77]:
print data
ind = data.argmin(axis=1)
print ind
print range(data.shape[0])
print data[range(data.shape[0]),ind]
In [79]:
a = np.arange(0,40,10)
print a
b = np.tile(a,(3,4))
print b
In [96]:
a = np.array([[4,3,5],[8,7,6],[1,2,8]])
print a
print '-----'
print np.sort(a,axis=0)
print '-----'
print np.sort(a,axis=1)
print '-----'
a.sort(axis=0)
print a
In [97]:
a = np.array([4,1,3,2])
j = np.argsort(a)
print j
print '-----'
print a[j]
In [ ]: