Hey there! Let's break down why you're running into this error and get your cost model working right.

The Root Causes of the Error #

There are two key issues in your code that are triggering the NameError:

1. Incorrect range checking: You're using == range(...) to verify if water_depth falls within a specific range—this doesn't work in Python. The range() function creates a range object, not a single value, so comparing a number directly to it will always return False.
2. Uncovered condition branch: When pl >= 1 but water_depth isn't in either of your specified ranges (0-50 or 51-150), spread_1 never gets assigned a value. Python throws a NameError because it can't find a variable that was never defined in this scenario.

Fixed Code with Explanations #

Here's the corrected version of your code, with notes on the changes:

# 项目现场水深（单位：米）
water_depth = 100
# 平台井需要自升式钻井平台（jackups）
pl = 1
# 复杂度1-2级需要LWIV
ss_simple = 1
# 复杂度3-4级需要钻井平台（rig）
ss_complex = 0
# 日费率
vjackup = 75000
jackup = 90000
vsemi = 170000
semi = 300000
lwiv = 200000

# 确定平台井的船舶编队成本
if pl >= 1:
    # 改用直接范围比较，既直观又符合Python语法
    if 0 <= water_depth <= 50:
        spread_1 = vjackup * 24.1
    elif 51 <= water_depth <= 150:
        spread_1 = jackup * 24.1
    else:
        # 新增else分支，覆盖所有未匹配的水深情况，避免spread_1未定义
        # 你可以根据实际业务逻辑调整默认值或添加提示
        spread_1 = 0
        print("Warning: Water depth is outside the expected range (0-150m)")
elif pl == 0:
    spread_1 = 0

# 测试输出结果
print(f"Platform well fleet cost: {spread_1}")

Key Changes Made: #

• Replaced == range(...) with direct range comparisons: Using 0 <= water_depth <=50 clearly and correctly checks if the value falls within the desired interval.
• Added an else clause for the depth check: This ensures spread_1 gets a value no matter what depth is provided, eliminating the NameError. Adjust the default value or logic here based on your actual cost rules.

内容的提问来源于stack exchange，提问作者fb03