Python编程入门到实践（一）

整理自《python编程从入门到实践》

1.安装文本编辑器Geany

首先确保已经安装了gcc与g++（一般的Linux都会有内置的）：

sudo apt-get install gcc
sudo apt-get install g++

接下来就是安装Geany：

sudo apt-get install geany

配置geany使用python3编译:build->set build commands:

 

2.list简介

motorcycles=['honda','yamaha','suzuki']
print(motorcycles)
motorcycles.append('ducati')#添加
print(motorcycles)
del motorcycles[0]#删除
print(motorcycles)
motorcycles.insert(0,'yamaha')#添加
print(motorcycles)
first_word=motorcycles.pop(0)#删除
print(first_word)
print(motorcycles)
motorcycles.remove('suzuki')#删除
print(motorcycles)
print(len(motorcycles))#长度
cars=['bmw','audi','toyota','subaru']
print(cars)
print(sorted(cars))#临时排序
print(cars)
cars.sort()#正排序
print(cars)
cars.sort(reverse=True)#倒排序
print(cars)
cars.reverse()
print(cars)

运行结果：

['honda', 'yamaha', 'suzuki']
['honda', 'yamaha', 'suzuki', 'ducati']
['yamaha', 'suzuki', 'ducati']
['yamaha', 'yamaha', 'suzuki', 'ducati']
yamaha
['yamaha', 'suzuki', 'ducati']
['yamaha', 'ducati']
2
['bmw', 'audi', 'toyota', 'subaru']
['audi', 'bmw', 'subaru', 'toyota']
['bmw', 'audi', 'toyota', 'subaru']
['audi', 'bmw', 'subaru', 'toyota']
['toyota', 'subaru', 'bmw', 'audi']

　　

 3.list operation

magicians=['alice','david','carolina']
for magician in magicians:
    print(magician.title()+",that was a great trick!")

#create numerical list
numbers=list(range(1,6))
even_numbers=list(range(2,11,2))
print(numbers)
print(even_numbers)

#以下两种方法结果相同
squares=[]
for value in range(1,11):
    square=value**2
    squares.append(square)
print(squares)

squares_1=[value**2 for value in range(1,11)]
print(squares)
print(min(squares))
print(max(squares))
print(sum(squares))

players=['a','b','c','d','e']
print(players)
print(players[-3:])#最后三个
#使用切片可复制列表
players_new=players[:]
#简单的复制会使两个变量指向同一个列表
players_new1=players
players.append('f')
print(players_new)
print(players_new1)

#不可变的列表被称为元组，但可重新定义
dimensions=(200,50)
for dimension in dimensions:
    print(dimension)
dimensions=(400,100)
for dimension in dimensions:
    print(dimension)

运行结果：

Alice,that was a great trick!
David,that was a great trick!
Carolina,that was a great trick!
[1, 2, 3, 4, 5]
[2, 4, 6, 8, 10]
[1, 4, 9, 16, 25, 36, 49, 64, 81, 100]
[1, 4, 9, 16, 25, 36, 49, 64, 81, 100]
1
100
385
['a', 'b', 'c', 'd', 'e']
['c', 'd', 'e']
['a', 'b', 'c', 'd', 'e']
['a', 'b', 'c', 'd', 'e', 'f']
200
50
400
100

 

4.if语句

由于没什么特别的，这部分放的示例很少：

#if-elif-else结构
age=12
if age<14:
    price=0
elif age<18:
    price=5
else:
    price=10
print("Your admission cost is $"+str(price)+".")

#循环操作列表时要判断列表是否为空
requested_toppings=[]
if requested_toppings:
    for requested_topping in requested_toppings:
        do something
else:
    do something

运行结果：

Your admission cost is $0.

 

5.字典

alien_0={}#创建
alien_0['color']='green'#添加
alien_0['points']=5
print(alien_0)
alien_0['color']='yellow'#修改
print(alien_0)
del alien_0['points']#删除
print(alien_0)

{'points': 5, 'color': 'green'}
{'points': 5, 'color': 'yellow'}
{'color': 'yellow'}

遍历所有键值对：

user_0={
    'username':'efermi',
    'first':'enrico',
    'last':'fermi',
    }

for key,value in user_0.items():
    print("\nkey:"+key)
    print("value:"+value)

key:username
value:efermi

key:first
value:enrico

key:last
value:fermi

遍历所有键：

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

friends=['phil','sarah']
for name in favorite_languages.keys():
    print(name.title())
    
    if name in friends:
        print("  Hi "+name.title() +
            ", I see your favorite language is " +
            favorite_languages[name].title() + "!")

Edward
Phil
  Hi Phil, I see your favorite language is Python!
Jen
Sarah
  Hi Sarah, I see your favorite language is C!

　　

对包含重复元素的列表可以调用set()，要对列表进行排序可以使用函数sorted()，以下例为例：

遍历字典中的所有值：

favorite_languages={
    'jen':'python',
    'sarah':'c',
    'edward':'ruby',
    'phil':'python',
    }
    
print("The following languges have been mentioned:")
for language in set(favorite_languages.values()):
    print(language.title())

The following languges have been mentioned:
Ruby
Python
C

字典嵌套：

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())

Username: mcurie
	Full name: Marie Curie
	Location: Paris

Username: aeinstein
	Full name: Albert Einstein
	Location: Princeton