Syntax

round(number[, ndigits=0])

對 number 進行 四捨五入：

Args :

• number ：可正可負 。
• ngigits ：保留 ngigits 位 小數 。

Test

assert round(0.5) == 1.0
assert round(-0.5) == -1.0

assert round(12345.678, -5) == 0.0
assert round(12345.678, -4) == 10000.0
assert round(12345.678, -3) == 12000.0
assert round(12345.678, -2) == 12300.0
 

assert round(12345.678, -1) == 12350.0
assert round(12345.678, 0) == 12346.0 == round(12345.678)
assert round(12345.678, 1) == 12345.7
assert round(12345.678, 2) == 12345.68
assert round(12345.678, 3) == 12345.678
assert round(12345.678, 4) == 12345.6780

round 陷阱

舉例

print round(1.045, 2)
print round(1.055
 
, 2)

列印結果：

1.04
1.05

原因