Putting matlab code into python

Question

I got a little problem in putting the code from matlab into python, i know how to make loops and stuff but the double equal sign is the same as function is member and I have no idea how to put it in python

for i=1:49
 if path==var(path(1),i) == 0 & var(path(1),i) ~= 0
 path(1,2) = var(r,i);
 var2(i,1:2) = path;
 path(1,1:2);
 a = a+1;
 two_connections(a,:) = path;

• Katriel: What is path? What does var(..., i) do? (The docs don't allow that construction: mathworks.com/help/techdoc/ref/var.html.) What is this code means to do?
• Eli Bendersky: == has the same meaning in Matlab as in Python. Your question is unclear
• kelm: @katrielalex: I'm guessing var in this case is an array that he defined elsewhere, rather than the function.

Answer 1

The double double equal sign in Matlab tests whether each value is equivalent.

In other words (a==b==c) will evaluate to 1 if a,b,c are equivalent, and 0 otherwise (even if a==b.)

It is sufficient to ensure that a==b and b==c (or a==b and a==c, etc.)

The tilde equals sign is simply "not equal to".

So your if statement would look like:

if (path == 0) and (var(path(1),i) == 0) and (var(path(1),i) != 0):

• Lauritz V. Thaulow: Note that is and == is not equivalent. If you create a class Z with this method: def __eq__(self, other): return 0 == other, then Z() == 0 is True, while Z() is 0 is False. I think a is b is equivalent to id(a) == id(b).
• jedwards: That is a very good point and I didn't mean to be misleading. In this case, however, both statements will evaluate the same way.
• jsbueno: -can you edit your answer so that "is" is not shown as equivalent to "==" ? Otherwise it deserves to be downvoted
• jedwards: @jsbueno -- I had thought about that, but didn't want to destroy the context of the comments -- but per your suggestion, I deleted it -- thanks!