一、遍历数组(操作Value)
1.使用二维列表遍历二维数组
python 创建List二维列表
lists = [[] for i in range(3)] # 创建的是多行三列的二维列表
for i in range(3):
lists[0].append(i)
for i in range(5):
lists[1].append(i)
for i in range(7):
lists[2].append(i)
print("lists is:", lists)
# lists is: [[0, 1, 2], [0, 1, 2, 3, 4], [0, 1, 2, 3, 4, 5, 6]]
输出数组行和列数
# 输出数组的行和列数
arr = [[1,4,7,10,15], [2,5,8,12,19], [3,6,9,16,22], [10,13,14,17,24]]
print arr.shape # (4, 5)
# 只输出行数
print arr.shape[0] # 4
# 只输出列数
print arr.shape[1] # 5
或者：
In [48]: arr = [[1,4,7,10,15], [2,5,8,12,19], [3,6,9,16,22], [10,13,14,17,24]]
In [49]: len(arr) #行数
Out[49]: 4
In [50]: len(arr[0]) #列数
Out[50]: 5
使用二维列表索引遍历二维列表
注意python中二维列表和matlab以及C和JAVA中一样，不需要每行中列的数量相等
sum_0 = 0
for i in range(len(lists)):
for j in range(len(lists[i])):
print(lists[i][j])
sum_0 += lists[i][j]
print("The sum_0 of Lists:", sum_0)
# 0
# 1
# 2
# 0
# 1
# 2
# 3
# 4
# 0
# 1
# 2
# 3
# 4
# 5
# 6
# The sum of Lists: 34
使用二维列表句柄遍历二维列表
sum_1 = 0
for i in lists:
for j in i:
sum_1 += j
print("The sum_1 of Lists:", sum_1)
# The sum_1 of Lists: 34
2.利用二维列表索引(类似C++)
注：一定要确保二维列表每行列数相同，否则会报错。因为Python允许二维数组列数不同
import numpy as np
world=np.zero([5,5])
for i in range(0,world.shape[0])
for j in range(0,world.shape[1])
print (world[i][j])
3.利用列表句柄
list2d = [[1,2,3],[4,5]]
sum = 0
for i in list2d:
for j in i:
sum += j