If else statement planets

Question

所以我想做一個程序來計算不同星球上的體重。這很令人沮喪，因爲它不能正確計算。

if ("Mercury" or "mercury" == planetName):       
    weight = weightObject * mercury 
elif ("Venus" or "VEnus" == planetName):      
    weight = weightObject * venus     
elif ("Earth's Moon" or "Earths Moon" == planetName):      
    weight = weightObject * earthsmoon 
elif ("Mars" or "MArs" or "MARS" == planetName):      
    weight = weightObject * mars 
elif ("Jupiter" or "JUpiter" == planetName):      
    weight = weightObject * jupiter 
elif ("Saturn" or "saturn" == planetName):      
    weight = weightObject * saturn 
elif ("uranus" or "Uranus" == planetName): 
    weight = weightObject * uranus 
elif ("neptune" or "Neptune" == planetName): 
    weight = weightObject * neptune 
elif ("pluto" or "Pluto" == planetName): 
    weight = weightObject * pluto 
else: 
    weight = -1 

#To print out the planet and weight and make sure its a planet and non negative number 
#It will not calculate a negative weight or different planet than listed 

if (weightObject > 0): 
print("The weight of the object on",planetName,"is {0:,.2f}".format(weight)) 
else: 
    print("Error: Planet name not found or number was negative. Please try  again.") 

如果我爲每個星球輸入20.5，它會給我所有人的完全相同的數字。有人可以幫忙嗎？

Answer 1

像"Mercury" or "mercury" == planetName這樣的聲明不會做你想要的。

你必須給他們分開來寫像("Mercury" == planetName) or ("mercury" == planetName)

使用字典來獲得從名字的因素可能是一個很好的選擇。

Answer 2

嘗試if ("Mercury"==planetName or "mercury"==planetName) ...

等上下行。由於if ("Mecury")評估結果爲true，您的第一條陳述很可能正在執行。

Answer 3

if ("Mercury" or "mercury" == planetName):       
    weight = weightObject * mercury 

應該

if planetName == 'Mercury' or planetName == 'mercury'       
    weight = weightObject * mercury 

或更簡潔

if planetName in ("Mercury", "mercury"):       
    weight = weightObject * mercury 

甚至

if planetName.lower() == 'mercury' 

Answer 4

嘗試：

if(planetName in ["Mercury", "mercury"]) 

或簡單：

planetName.lower() == "mercury" 

而且，這將是一個好主意，你打開了一個Python解釋器，並開始喜歡打字的東西：

bool("Mercury") 
"Mercury" == "mercury" 
"Mercury" and "mercury" == "Mercury" 
"Mercury" or "mercury" == "Mercury" 
bool(None) 
bool(True) 
bool(False) 
bool([]) 
bool({}) 
bool([1]) 
bool({"a":"a"}) 

獲取知道什麼計算結果爲真在python和什麼評估爲false。它會讓你的生活變得更輕鬆：D

或者另一個很酷的把戲把你的值乘以字典。

weights = {"mercury": mercury, "venus": venus, "Earth's Moon": earthsmoon, "Earths Moon": earthsmoon .... etc.} 
try: 
    weight = weights[planetName.lower()] * weightObject 
except KeyError: 
    weight = -1 

if weight > 0: 
    .......