Python字典

指剑的剑

2024-07-22 帮助2人

#字典
‘’’

语法：
字典名 = {'键':'值','键':'值',....}
例如：

test = {'color':'pink','points':7}
print(test['color'])
print(test['points'])

‘’’

#例2：test中的键和值不变，我们从字典中获取相关的键和值，把这个值储存在new_points中
#再如下操作中，需要将new_points的整数类型转化为字符串

new_points = test['points']
print("You just earned "   str(new_points)   "points !")

#例3

test = {'color':'pink','points': 7 }
print(test)

test['x_position'] = 0  #给字典添加新的键值对，键为 x_position,值为0
test['y_position'] = 25 #给字典添加新的键值对，键为 y_position,值为25
print(test)

#例4：创建空字典

test1 = { }
#分行添加新的键值对
test1['color'] = 'blue'
test1['points'] = 5

print(test1)

#例5：更改字典中键对值内容

test2 = {'color':'red'}
print('The color is '   test2['color']   '.')
#将red修改为pink
test2['color'] = 'yellow'
print("The test2 new color is "   test2['color']   '.')

#例6：

test3 = {'x_position':0,'y_position':25,'speed':'medium'}
print('Original x-position:'   str(test3['x_position'])  )
#向右移动test
#据外星人当前速度决定将其移动多远
if test3['speed'] == 'slow':
    x_increment = 1
elif test3['speed'] = 'medium':
    x_increment = 2
else:
    # test3 速度过快
    x_increment = 3
test3['x_position'] = test3['x_position']   x_increment
print('New x-position:'   str(test3['x_position']))

#例7:删除键值，使用del语句指定字典名和要删除的键

test4{'color':'white','points':9}
print(test4)

del test4['points']  #del语句是彻底删除
print(test4)

#例8：使用多行定义字典，输入左花括号后按回车，缩进，指定键值对

test5 = {
    'name':'test5',
    'number':5,
    'power':'88W',
    }
print('The user is:'   test5['name'].title()   '.') #此处title()是将test5以标题形式展出

#例9:

test6 = {
    'username':'test6',
    'first':'t',
    'last':6,
    }
#用for循环遍历字典，声明2个变量用来存储键和值，
#接下来的for循环中，python将每个键值储存在key，value2个变量中

for k,v in test6.items():
    print("\nKey:"   k)
    print("Value:"   v)

#例10：

favorite_languages = {
    'jen':'python',
    'sarah':'c',
    'edward':'ruby',
    'phil':'python',
    }

#用for循环遍历字典，声明2个变量用来存储键和值，
#将键存储在变量name中，值存储在变量languages中
for name,language in favorite_languages.items():
    print(name.title()   "'s favorite language is "  
          language.title()   ".")

#例11：

favorite_languages = {
    'jen':'python',
    'sarah':'c',
    'edward':'ruby',
    'phil':'python',
    }
#使用方法key()提取字典中所有的键，并把键存储到变量name中
for name in favorite_languages.key():
    print(name.title())

#例12:

favorite_languages = {
    'jen':'python',
    'sarah':'c',
    'edward':'ruby',
    'phil':'python',
    }
friends = ['phil','sarah']
for name in favorite_language.keys():
    print(name.title())
    if name in friends:
        #if 测试，如果名字在列表friends中，就打印一句问候语
        print('Hi'   name.title()   ', I see your favorite language is'   favorite_languages[name].title()   '!')

#例13：

favorite_languages = {
    'jen':'python',
    'sarah':'c',
    'edward':'ruby',
    'phil':'python',
    }
if 'erin' not in favorite_languages.keys():
    print('Erin,Please take our poll !')

#例14：

favorite_languages = {
    'jen':'python',
    'sarah':'c',
    'edward':'ruby',
    'phil':'python',
    }
#使用函数sorted对列表临时排序。让python列出所有键，在遍历前进行排序
for name in sorted(favorite_languages.keys()):
    print(name.title()   ', thank you for taking the poll .')

#例15:

favorite_languages = {
    'jen':'python',
    'sarah':'c',
    'edward':'ruby',
    'phil':'python',
    }
print('The follwing language have been memtioned :')
for language in set favorite_languages.values():
#注意上行代码中的 set  用集合set可以剔除重复项python
#此处用values()方法提取字典的值
    print(language.title())

#例16：

test_1 = {'color':'white','point':5}
test_2 = {'color':'pink','point':6}
test_3 = {'color':'blue','point':8}
#将3个字典放入列表tests中
tests = [test_1,test_2,test_3]
#使用for循环遍历列表
for test in tests:
    print(test)

#例17：
#创建一个用于储存test的空列表

tests = []

#创建30个红色的test
#使用函数 range()生成30个test
for test_number in range(30):
#创建new_test字典，包含3对键值
    new_test = {'color':'red','points':5,'speed':'slow'}
    tests.append(new_test)
#显示前5个test
for test in tests[:5]:
    print(test)
print('...')
#显示创建多少个test
print('Total number of tests:'   str(len(aliens)))

#例18：
#创建一个用于储存test的空列表

tests = []

#创建30个红色的test
#使用函数range()打印0-29
for test_number in range(0,30):
#创建new_test字典，包含3对键值
    new_test = {'color':'red','points':5,'speed':'slow'}
    tests.append(new_test)
#for循环，指定索引0-3，也就是元素0  1 2
for test in tests[0:3]:
#使用if进行测试，检查键是否等于red，如果通过，执行if测试后面缩进的代码
    if test['color'] == 'red':
        test['color'] = 'yellow'
        test['speed'] = 'medium'
        test['points'] = 10
#显示前5个test
for test in tests[:5]:
    print(test)
print('...')

#例19：
#存储所有点披萨的信息

pizza = {
    'crust':'thick',
    'toppings':['mushrooms','extra cheese'],  #此处在字典中嵌套列表
    }
#概述所点的披萨
print('You ordered a '   pizza['crust']   '-crust pizza'  
      'with the following toppings:')

for topping in pizza['toppings']:
    print('\t'   topping)

#例20：

favorite_language = {
    'jen':['python','ruby'],
    'sarah':['c'],
    'edward':['ruby','go'],
    'phil':['python','haskell'],
    }

for name,language in favorite_languages.items():
    print('\n'  name.title()   "'s favorite languages are:")
    for language in languages:
        print('\t'   language.title())

#例21：

users = {'aeinstein':{'first':'albert',
                      'last':'einstein',
                      'location':'princeton'},
         'mcurie':{'first':'marie',
                   'last':'curie',
                   'location':'paris',},
         }
for username,user_info in users.items():
    print("\nUsername:"   username)
    full_name = user_info['first']   " "   user_info['last']
    location= user_info['location']

print("\tFull name:"   full_name.title())
print("\tLocation:"   location.title())

这篇好文章是转载于：学新通技术网

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