This seems to be because multiplication of small numbers is optimized in CPython 3.5, in a way that left shifts by small numbers are not. Positive left shifts always create a larger integer object to store the result, as part of the calculation, while for multiplications of the sort you used in your test, a … Read more
Python works: >>> sum(x for x in xrange(1000000000 + 1)) 500000000500000000 Or: >>> sum(xrange(1000000000+1)) 500000000500000000 Python’s int auto promotes to a Python long which supports arbitrary precision. It will produce the correct answer on 32 or 64 bit platforms. This can be seen by raising 2 to a power far greater than the bit width … Read more
For integers: Use arithmetic expansion: $((EXPR)) num=$((num1 + num2)) num=$(($num1 + $num2)) # Also works num=$((num1 + 2 + 3)) # … num=$[num1+num2] # Old, deprecated arithmetic expression syntax Using the external expr utility. Note that this is only needed for really old systems. num=`expr $num1 + $num2` # Whitespace for expr is important For … Read more