python - Python字典中的键/值混淆

这段代码可以完成预期的工作。我的挂断电话是了解字典中的键是什么，值是什么。我（仍然是）确信它是-dict = {key：value}-但是在运行下面的代码时，情况似乎恰恰相反。有人可以让我休息一下，弄清楚我所缺少的吗。我不想继续深入了解它。谢谢。

prices = {
"banana" : 4,
"apple"  : 2,
"orange" : 1.5,
"pear"   : 3,
}
stock = {
"banana" : 6,
"apple"  : 0,
"orange" : 32,
"pear"   : 15,
}

total = 0
for key in prices:
    print key
    print "price: %s" % prices[key]
    print "stock: %s" % stock[key]
    total = total + prices[key]*stock[key]
print

print total

输出：

orange
price: 1.5
stock: 32

pear
price: 3
stock: 15

banana
price: 4
stock: 6

apple
price: 2
stock: 0

117.0
None

最佳答案

您的理解是正确的，它是{key：value}，并且您的代码对此进行了备份。

for key in prices:  # iterates through the keys of prices ["orange", "apple", "pear", "banana"] (though no ordering is guaranteed)
    print key # prints "orange"

    print "price: %s" % prices[key] # prints prices["orange"] (1.5)
    # which means it prints the value of the prices dict, orange key.

    print "stock: %s" % stock[key] # prints stock["orange"] (32)
    #which means it prints the value of the stock dict, orange key.

这正是您应该期望的。您的困惑在哪里（即与您描述的相反）在哪里？

关于python - Python字典中的键/值混淆，我们在Stack Overflow上找到一个类似的问题：https://stackoverflow.com/questions/27663707/