In Python, / and // are two different division operators with different behaviors and purposes.
The / operator represents an ordinary division operation. When using the / operator, Python performs floating-point division and returns the floating-point value of the result. For example:
result = 9 / 2
print(result) # 输出 4.5
Even if the operands are integers, the result of using the / operator will be a floating point number.
// Operator means Floor Division. When using the // operator, Python performs integer division and returns the integer part of the result. The result will be rounded down, that is, the fractional part will be discarded. For example:
result = 9 // 2
print(result) # 输出 4
// Operators always return integer results, even if one or both operands are floats.
In particular, it's worth noting that when using the // operator to divide by negative numbers, the result will be drawn towards negative infinity, not towards zero. For example:
result = -9 // 2
print(result) # 输出 -5
In this example, -9 divided by 2 results in -4.5, which is rounded down to -5.
Therefore, the / operator performs floating-point division, while the // operator performs integer division and returns the integer portion of the result.