Why doesn't Python have a 'do while' loop like many other programming language, such as C?
Example : In the C we have do while loop as below :
do {
statement(s);
} while( condition );
There is no do...while
loop because there is no nice way to define one that fits in the statement: indented block
pattern used by every other Python compound statement. As such proposals to add such syntax have never reached agreement.
Nor is there really any need to have such a construct, not when you can just do:
while True:
# statement(s)
if not condition:
break
and have the exact same effect as a C do { .. } while condition
loop.
See PEP 315 -- Enhanced While Loop:
Rejected [...] because no syntax emerged that could compete with the following form:
while True: <setup code> if not <condition>: break <loop body>
A syntax alternative to the one proposed in the PEP was found for a basic do-while loop but it gained little support because the condition was at the top:
do ... while <cond>: <loop body>
or, as Guido van Rossum put it:
Please reject the PEP. More variations along these lines won't make the language more elegant or easier to learn. They'd just save a few hasty folks some typing while making others who have to read/maintain their code wonder what it means.