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Python Python Basics All Together Now Branch and Loop

Posted by JASON PETERSEN
JASON PETERSEN
14,266 Points

Is >= 1 better than > 0?

In masterticket.py, the instructor chose to use:

 while tickets_remaining >= 1:

while I chose to use:

while tickets_remaining > 0:

Is one better than the other? Why/why not?

Thanks!

1 Answer

Chris Freeman
MOD
Chris Freeman
Treehouse Moderator 68,423 Points
Chris Freeman
Chris Freeman
Treehouse Moderator 68,423 Points

Hey JASON PETERSEN, great question. I believe that both cases are optimized by the parser. Using timeit a performance analysis says they’re are equivalent:

import timeit

def gt_zero():
    for x in range(100):
        if x > 0:
            pass

def ge_one():
    for x in range(100):
        if x >= 1:
            pass

print(timeit.timeit("gt_zero()", setup="from __main__ import gt_zero"))
print(timeit.timeit("gt_zero()", setup="from __main__ import gt_zero"))
print(timeit.timeit("ge_one()", setup="from __main__ import ge_one"))
print(timeit.timeit("ge_one()", setup="from __main__ import ge_one"))

# yields after 1_000_000 calls
# 28.21725383333296
# 28.741845541666407
# 28.536575374999757
# 28.496736958332804

In this StackOverflow post it demonstrates that gt and gte both execute in equal time since they both have a single opcode representation.

Disassembled Python says they’ll execute in the same number of instructions:

import dis

def gt0():
    if x > 0:
        pass

def ge1():
    if x >= 1:
        pass

print("dis gt0")
dis.dis(gt0)

print("dis ge1")
dis.dis(ge1)

yields

dis gt0
 21           0 LOAD_GLOBAL              0 (x) 
              3 LOAD_CONST               1 (0) 
              6 COMPARE_OP               4 (>) 
              9 POP_JUMP_IF_FALSE       15 

 22          12 JUMP_FORWARD             0 (to 15) 
        >>   15 LOAD_CONST               0 (None) 
             18 RETURN_VALUE         
dis ge1
 25           0 LOAD_GLOBAL              0 (x) 
              3 LOAD_CONST               1 (1) 
              6 COMPARE_OP               5 (>=) 
              9 POP_JUMP_IF_FALSE       15 

 26          12 JUMP_FORWARD             0 (to 15) 
        >>   15 LOAD_CONST               0 (None) 
             18 RETURN_VALUE

So, there is no practical difference. Use the one that would give the better readability.

Post back if you need more help. Good luck!!!