python中append实例用法总结

a=[1,2,3]

a.append(5)

a=[1,2,3]

a.append([5])

import numpy as np

a=[] 

for i in range(5): 

  a.append([])

  for j in range(5): 

    a[i].append(i)

[[0, 0, 0, 0, 0],

 [1, 1, 1, 1, 1],

 [2, 2, 2, 2, 2],

 [3, 3, 3, 3, 3],

 [4, 4, 4, 4, 4]]

a=np.transpose(a)

([[0, 1, 2, 3, 4],

   [0, 1, 2, 3, 4],

   [0, 1, 2, 3, 4],

   [0, 1, 2, 3, 4],

   [0, 1, 2, 3, 4]])

h=np.arange(-2,2,1)

h.shape

k1=np.c_[h,h] #横向合并函数1 np.c_，将数组转化为列向量

k2=np.hstack((h,h)) #横向合并函数2 np.hstack，将数组作为横向量

print("k1="+str(k1))

print("k2="+str(k2))

l1=np.r_[[h],[h]] #纵向合并函数np.r_

l2=np.vstack((h,h)) #纵向合并函数np.vstack

print("l1="+str(l1))

print("l2="+str(l2))

k1=[[-2 -2]

 [-1 -1]

 [ 0 0]

 [ 1 1]]

k2=[-2 -1 0 1 -2 -1 0 1]

l1=[[-2 -1 0 1]

 [-2 -1 0 1]]

l2=[[-2 -1 0 1]

 [-2 -1 0 1]]

ls1 = [1,2,3,4,5,6]
ls2 = [1,2,3,4,5,6]
ls1.append(12)
 
#可以添加列表，字典，元组，集合，字符串等
ls2.append([1,"a"])  #添加列表
ls2.append({2:"a",3:"hj"}) #添加字典
ls2.append((1,"k",3)) #添加元组
ls2.append({"1","2","h"}) #添加集合
ls2.append("123abc") #添加字符串
 
print(ls1.append(12)) #无返回值
print(ls1) #append()函数的操作对象是原列表。
print(ls2)

None
[1, 2, 3, 4, 5, 6, 12, 12]
[1, 2, 3, 4, 5, 6, [1, 'a'], {2: 'a', 3: 'hj'}, (1, 'k', 3), {'2', '1', 'h'}, '123abc']