Python中phaseout设为2时触发NameError或返回空元组的问题求助

我运行Python代码时遇到了NameError问题：当phaseout变量设为2时，要么程序提示phasedays未定义，要么初始化phasedays为空元组后返回空值。但phaseout设为1时程序运行完全正常。

问题代码片段 #

character = input("What character are you saving for? ")
phaseout = int(input("What phase is " + character + " coming out in? (1 or 2): "))
currentphase = int(input("Current phase (1 or 2): "))
daysleftinphase = int(input("Days left in current phase: "))

# phase calculations
# does NOT include the 20 days for the phase the desired character is out
phasedays = ('')
if currentphase == 1:
  if phaseout == 1:
    phasedays = 20 + daysleftinphase
elif currentphase == 1:
  if phaseout == 2:
    phasedays = 40 + daysleftinphase
elif currentphase == 2:
  if phaseout == 1:
    phasedays = daysleftinphase
elif currentphase == 2:
  if phaseout == 2:
    phasedays = 20 + daysleftinphase

print("\nDays you'll have when it comes to phases:", phasedays)

错误信息（未初始化phasedays时） #

Traceback (most recent call last):
    File "main.py", line 22, in <module>
        print("\nDays you'll have when it comes to phases:", phasedays)
NameError: name 'phasedays' is not defined

问题原因 #

你的条件判断逻辑存在语法错误：第一个if currentphase == 1已经覆盖了所有currentphase为1的情况，后续的elif currentphase == 1永远不会被执行。当currentphase=1且phaseout=2时，代码不会进入任何赋值分支——如果没初始化phasedays就触发NameError，初始化了就保留初始的空元组。

修正后的代码 #

character = input("你要攒哪个角色？")
phaseout = int(input(f"{character}会在哪个卡池阶段上线？(1或2): "))
currentphase = int(input("当前卡池阶段(1或2): "))
daysleftinphase = int(input("当前阶段剩余天数: "))

# 阶段计算（不包含目标角色上线阶段的20天）
phasedays = 0
if currentphase == 1:
    if phaseout == 1:
        phasedays = 20 + daysleftinphase
    elif phaseout == 2:
        phasedays = 40 + daysleftinphase
elif currentphase == 2:
    if phaseout == 1:
        phasedays = daysleftinphase
    elif phaseout == 2:
        phasedays = 20 + daysleftinphase

print(f"\n你能攒到的阶段天数: {phasedays}")

优化说明 #

• 修复条件分支逻辑：将currentphase的判断作为外层，内部用elif处理phaseout的不同情况，确保所有场景都能被覆盖。
• 初始值设为0：更符合数值计算的逻辑，避免空元组带来的类型混淆。
• 使用f-string简化字符串拼接：让输入输出代码更简洁易读。

内容的提问来源于stack exchange，提问作者user20444221