python学习第七篇——字典访问键与值

此程序的目的在于，正确而简单的访问字典的键与值

favorite_languages={
    'jen':['python','c'],
    'sarah':['c'],
    'edward':['ruby','go'],
    'phil':['python','java'],
    }
 #古老的方法访问字典中键与值
for element in favorite_languages:
    print(element +"'s favorite languages are:")
    print("	"+str(favorite_languages[element]))
# 正确的方法访问键与值
for name,languages in favorite_languages.items():
    print("
"+name.title()+"'s favorite languages are:")
    for language in languages:
        print("	"+language.title())

for name,languages in favorite_languages.items():
    if len(languages) == 1:
        print("
"+name.title()+"'s favorite languages is:")
    else:
        print("
"+name.title()+"'s favorite languages are:")
    for language in languages:
        print("	"+language.title())

1  代码中12-15行代码是正确而又简便的访问字典键与值的方式。注意for 后面可以跟两个变量，一个用来访问键，一个用来访问值。

2 .item()类可以方便的完成这种访问，实际上.item（）返回了两个列表,一个给了name,另一个给了languages.

3  注意第二个for循环的位置