在python中打印一个二维数组
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printing a two dimensional array in python
提问by user2548833
I have to print this python code in a 5x5 array the array should look like this :
我必须在 5x5 数组中打印此 python 代码，数组应如下所示：
0 1 4 (infinity) 3
1 0 2 (infinity) 4
4 2 0 1 5
(inf)(inf) 1 0 3
3 4 5 3 0
can anyone help me print this table? using indices.
谁能帮我打印这张表？使用索引。
for k in range(n):
for i in range(n):
for j in range(n):
if A[i][k]+A[k][j]<A[i][j]:
A[i][j]=A[i][k]+A[k][j]
回答by sihrc
I used numpy to generate the array, but list of lists array should work similarly.
我使用 numpy 来生成数组，但列表数组的列表应该类似地工作。
import numpy as np
def printArray(args):
print "\t".join(args)
n = 10
Array = np.zeros(shape=(n,n)).astype('int')
for row in Array:
printArray([str(x) for x in row])
If you want to only print certain indices:
如果您只想打印某些索引：
import numpy as np
def printArray(args):
print "\t".join(args)
n = 10
Array = np.zeros(shape=(n,n)).astype('int')
i_indices = [1,2,3]
j_indices = [2,3,4]
for i in i_indices:printArray([str(Array[i][j]) for j in j_indices])
回答by unutbu
A combination of list comprehensionsand strjoinscan do the job:
inf = float('inf')
A = [[0,1,4,inf,3],
[1,0,2,inf,4],
[4,2,0,1,5],
[inf,inf,1,0,3],
[3,4,5,3,0]]
print('\n'.join([''.join(['{:4}'.format(item) for item in row])
for row in A]))
yields
产量
0 1 4 inf 3
1 0 2 inf 4
4 2 0 1 5
inf inf 1 0 3
3 4 5 3 0
Using for-loopswith indices is usually avoidable in Python, and is not considered "Pythonic" because it is less readable than its Pythonic cousin (see below). However, you could do this:
在 Python 中使用带有索引的for 循环通常是可以避免的，并且不被认为是“Pythonic”，因为它的可读性不如它的 Pythonic 表亲（见下文）。但是，您可以这样做：
for i in range(n):
for j in range(n):
print '{:4}'.format(A[i][j]),
print
The more Pythonic cousin would be:
更 Pythonic 的表亲是：
for row in A:
for val in row:
print '{:4}'.format(val),
print
However, this uses 30 print statements, whereas my original answer uses just one.
但是，这使用了 30 个打印语句，而我的原始答案仅使用了一个。
回答by Andrei
using indices, for loops and formatting:
使用索引、for 循环和格式：
import numpy as np
def printMatrix(a):
print "Matrix["+("%d" %a.shape[0])+"]["+("%d" %a.shape[1])+"]"
rows = a.shape[0]
cols = a.shape[1]
for i in range(0,rows):
for j in range(0,cols):
print "%6.f" %a[i,j],
print
print
def printMatrixE(a):
print "Matrix["+("%d" %a.shape[0])+"]["+("%d" %a.shape[1])+"]"
rows = a.shape[0]
cols = a.shape[1]
for i in range(0,rows):
for j in range(0,cols):
print("%6.3f" %a[i,j]),
print
print
inf = float('inf')
A = np.array( [[0,1.,4.,inf,3],
[1,0,2,inf,4],
[4,2,0,1,5],
[inf,inf,1,0,3],
[3,4,5,3,0]])
printMatrix(A)
printMatrixE(A)
which yields the output:
产生输出：
Matrix[5][5]
0 1 4 inf 3
1 0 2 inf 4
4 2 0 1 5
inf inf 1 0 3
3 4 5 3 0
Matrix[5][5]
0.000 1.000 4.000 inf 3.000
1.000 0.000 2.000 inf 4.000
4.000 2.000 0.000 1.000 5.000
inf inf 1.000 0.000 3.000
3.000 4.000 5.000 3.000 0.000
回答by Souradeep Nanda
There is always the easy way.
总有简单的方法。
import numpy as np
print(np.matrix(A))
回答by Ema
print(mat.__str__())
where mat is variable refering to your matrix object
其中 mat 是指您的矩阵对象的变量
回答by AlexP
In addition to the simple print answer, you can actually customise the print output through the use of the numpy.set_printoptionsfunction.
除了简单的打印答案之外，您实际上可以通过使用numpy.set_printoptions函数来自定义打印输出。
Prerequisites:
先决条件：
>>> import numpy as np
>>> inf = np.float('inf')
>>> A = np.array([[0,1,4,inf,3],[1,0,2,inf,4],[4,2,0,1,5],[inf,inf,1,0,3],[3,4,5,3,0]])
The following option:
以下选项：
>>> np.set_printoptions(infstr="(infinity)")
Results in:
结果是：
>>> print(A)
[[ 0. 1. 4. (infinity) 3.]
[ 1. 0. 2. (infinity) 4.]
[ 4. 2. 0. 1. 5.]
[(infinity) (infinity) 1. 0. 3.]
[ 3. 4. 5. 3. 0.]]
The following option:
以下选项：
>>> np.set_printoptions(formatter={'float': "\t{: 0.0f}\t".format})
Results in:
结果是：
>>> print(A)
[[ 0 1 4 inf 3 ]
[ 1 0 2 inf 4 ]
[ 4 2 0 1 5 ]
[ inf inf 1 0 3 ]
[ 3 4 5 3 0 ]]
If you just want to have a specific string output for a specific array, the function numpy.array2stringis also available.
如果您只想为特定数组输出特定字符串，也可以使用函数numpy.array2string。
