Stata是否会在名为"P"的矩阵上窒息?

问题描述

因此，定义一个名为"Z"的矩阵并显示其第一个元素会很好:

So defining a matrix named "Z", and displaying its first element works nicely:

. matrix Z = J(1,3,0)
. matrix list Z

Z[1,3]
    c1  c2  c3
r1   0   0   0

. di el(Z,1,1)
0

另一方面，仅将名称更改为"P"会破坏el()的功能:

On the other hand simply changing the name to "P" breaks the function of el():

. matrix P = J(1,3,0)
. matrix list P

P[1,3]
    c1  c2  c3
r1   0   0   0

. di el(P,1,1)
type mismatch

为什么?

更新1:

在发现上述行为时(在调试会话期间)，我从命令行和ado文件进行了复制，然后在用clear，drop program _all和matrix drop _all清除了Stata之后进行了复制.但是，重新启动Stata后，我无法重现该行为.

While finding the above behavior (during a debug session), I reproduced from command line and from an ado file, then reproduced after clearing Stata with clear, drop program _all and matrix drop _all. However, upon restarting Stata, I am unable to reproduce the behavior.

更新2:

至少我曾经使用过clear ... ...进一步的研究表明，如果我在内存中有一个名称以"P"开头的变量，则可以在重新启动时重现该行为.例如(重新开始Stata):

At least I thought I used clear... further investigation shows that I can reproduce the behavior on restart if I have a variable with a name starting with "P" in memory. For example (starting Stata fresh):

. matrix P = J(1,3,0)
. matrix list P
. di el(P,1,1)
0

. set obs 100
obs was 0, now 100
. gen Parsnips = uniform()
(100 real changes made)
. di el(P,1,1)
type mismatch
. rename Parsnips parsnips
. di el(P,1,1)
0

推荐答案

在我的第二次更新表明的情况下，Indeed Stata确实与命名歧义冲突.根据我刚从他们的技术支持部门获得的反馈，使用di el(matrix(P),1,1)明确地将P称为矩阵可以解决此问题.

Indeed Stata does collide with naming ambiguity in such a case as my second update indicates. Per feedback I just received from their technical support, using di el(matrix(P),1,1) to explicitly refer to P as a matrix resolves this issue.

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