What is the answer of [(4 -2 ) /2 , 5 +6 , 7 , 8 ] ? Why does MATLAB output [1 5 6 7 8]？

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qqffssxx
qqffssxx 2023-2-24
编辑： Stephen23 2023-2-24
Ran in:
When the plus sign is preceded by a blank space：
[(4 -2 ) /2 , 5 +6 , 7 , 8 ]
ans = 1×5
1 5 6 7 8
Delete blank space：
[(4 -2 ) /2 , 5+6 , 7 , 8 ]
ans = 1×4
1 11 7 8
I don't understand why MATLAB will output different results.
Under normal circumstances, shouldn't spaces be ignored？

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采纳的回答

VBBV
VBBV 2023-2-24
[5 +6]
Is not equivalent to
5+6
When you use concatenate operator [ ]

更多回答（3 个）

qqffssxx
qqffssxx 2023-2-24
I got it!
[1 +3 +5 ] == [1 3 5]
Askic V
Askic V 2023-2-24
编辑：Askic V 2023-2-24
Ran in:
In Matalb, when you define an array (or vector) you can use the following syntax:
v = [1 3 4 5 6]
v = 1×5
1 3 4 5 6
This is exactly the same as:
v = [1, 3, 4, 5, 6]
Steven Lord
Steven Lord 2023-2-24
See this documentation page for more information.
  1 个评论
Stephen23
Stephen23 2023-2-24
编辑：Stephen23 2023-2-24
Ran in:
There is nothing on that page that explicitly explains how space is interpreted around arithmetic operators when building arrays:
[1 - 2]
ans = -1
[1 -2]
ans = 1×2
1 -2
This topic comes up fairly regularly on Answers, indicative of confusion regarding this topic, and that page looks like a good place to document it. None of the other "obvious" pages I found in a quick search now covered this topic either, e.g.:
https://www.mathworks.com/help/matlab/math/creating-and-concatenating-matrices.html

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