Python-like else clause on for loops in Julia?

[kilminster]

Python's for-else construct as described for example in section 4.4, here, is sometimes very useful. (The idea is that the else clause will be executed after the loop completes normally, but not if we break out of the loop.) Could something similar be added to Julia?

As an example, code like:

converged=true
for i=1:n
    if !isapprox(y[i],ynew[i])
        converged=false
        break
    end
end
if converged
    return y
end

could become:

for i=1:n
    if !isapprox(y[i],ynew[i])
        break
    end
else
    return y
end

[jiahao]

Please try searching the existing issues before you open a new one.

Duplicate of #1289

[kilminster]

I'm sorry, I did try searching, obviously not well enough.

[jiahao]

No worries, it can be hard to search for things on Github.

For your use case, you can write something like

for i=1:n
    if y[i] ≈ ynew[i]
        @goto converged
    end
    y, ynew = ynew, computenewy(y, ynew)
end
error("Not converged")
@label converged
return y

which was what emerged from the discussion in that referenced issue.