在python中声明和填充二维数组
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Declaring and populating 2D array in python
提问by Dangila
I want to declare and populate a 2d array in python as follow:
我想在 python 中声明并填充一个二维数组，如下所示：
def randomNo():
rn = randint(0, 4)
return rn
def populateStatus():
status = []
status.append([])
for x in range (0,4):
for y in range (0,4):
status[x].append(randomNo())
But I always get IndexError: list index out of range exception. Any ideas?
但我总是得到 IndexError: list index out of range 异常。有任何想法吗？
采纳答案by Itay Karo
The only time when you add 'rows' to the status array is before the outer for loop.
So - status[0]exists but status[1]does not.
you need to move status.append([])to be inside the outer for loop and then it will create a new 'row' before you try to populate it.
将“行”添加到状态数组的唯一时间是在外部 for 循环之前。
所以 -status[0]存在但status[1]不存在。
您需要移动status.append([])到外部 for 循环内，然后它会在您尝试填充它之前创建一个新的“行”。
回答by justhalf
You haven't increase the number of rows in statusfor every value of x
您没有status为每个值增加行数x
for x in range(0,4):
status.append([])
for y in range(0,4):
status[x].append(randomNo())
回答by Shayne
Try this:
尝试这个：
def randomNo():
rn = randint(0, 4)
return rn
def populateStatus():
status = {}
for x in range (0,4):
status [x]={}
for y in range (0,4):
status[x][y] = randomNo()
This will give you a 2D dictionary you can access like val=status[0,3]
这将为您提供一个 2D 字典，您可以像这样访问 val=status[0,3]
回答by Pierre H.
If you're question is about generating an array of random integers, the numpy module can be useful:
如果您的问题是关于生成随机整数数组，则 numpy 模块可能很有用：
import numpy as np
np.random.randint(0,4, size=(4,4))
This yields directly
这直接产生
array([[3, 0, 1, 1],
[0, 1, 1, 2],
[2, 0, 3, 2],
[0, 1, 2, 2]])
回答by Shayne
More "modern python" way of doing things.
更多“现代蟒蛇”的做事方式。
[[ randint(0,4) for x in range(0,4)] for y in range(0,4)]
Its simply a pair of nested list comprehensions.
它只是一对嵌套的列表推导式。
