Check whether break condition was triggered

Question

Is there an elegant way in Python to detect whether a break condition was engaged at the last iteration or never at all?

C++ example:

int k, n = 10;
for (k = 0; k < n; k++)
    if (condition) break;

if (k == n) cout << "Never broke\n";
else        cout << "Broke at " << k << '\n';

Python example:

n = 10
for k in range(n):
    if condition: break

if k == n: print("Never broke")
else:      print("Broke at", k)

In Python, we don't know whether condition was true at the last iteration since k is 9 in both cases.

Why not just use range(n + 1) instead? Because on some contexts, we might get an "index out of range" error when k is n.

One possible workaround is to use a sentinel value as shown below, but is there a better way?

n, flag = 10, True
for k in range(n):
    if condition:
        flag = False
        break

if flag: print("Never broke")
else:    print("Broke at", k)

Answer 1

Use for/else. That's specifically what it's for.

for k in range(n):
    if condition:
       print("Broke at", k)
       break
else:
    print("Never broke")