message = "hello python!"
print(message)- 变量可以随时赋予新的值
- 变量名只能包含字母、数字和下划线，且不能以数字开头
print(message.title())
#.title(): make each words begins with captial letter.
# method, an action that python can perform on a piece of data.
# .upper() 全部大写
# .lower() 全部小写
frist_name = "ada"
last_name = "lace"
full_name = first_name + "·" + last_name
# 合并字符串： +
print(full_name.title())
# fromart- 换行， 空白，删除空白
print("\tpython") # \t 制表符 print("python\n") # \n 换行符 language = "python " # 末尾有空白符号 print(language.rstrip()) # 暂时删除空白符号 # rstrip() 删除右空白 # lstrip() 删除左空白 # strip() 删除两端空白 language = language.rstrip() # 永久删除变量中空白 # 单引号表达字符串时中间不应有‘号，否则会终止
age = 23
message = "Happy " + str(age) + "rd Birthday! "
#显式表达整数作为字符串: str()
print(message)bycile = ['trek', 'cannodale', 'redline', 'specialized']
print(bycilep[0].title()) # produce "Trek"
print(bycile[-1].title()) # produce "Specilized" motorcycle = ['honda', 'yamha', 'suzuki']
# 改变列表元素值
motorcycle[0] = 'ducati'
# 在列表末尾添加元素
motorcycle.append('ducati')
# insert() : 任意位置添加元素
motorcycle.insert(0, 'ducati')
# 删除元素
# del 语句, 不再使用该列表元素值
del motorcycle[0]
# pop() 删除列表末尾的元素; 并将被删除元素付给新的变量
poped_motorcycle = motorcycle.pop()
# pop()删除任意位元素， 仍可使用该列表元素值
first_owned = motorcycle.pop(0)
# remove(): 根据值确定删除对象，仍可使用该对象
too_expensive = 'ducati'
motorcycle.remove(too_expensive)
print("\nA " + too_expensive .title() + "is too expensive for me.") # sort() 依照字母顺序永久排序
# 依字母顺序反向排序
cars = ['bwm', 'audi', 'toyta', 'subara']
print(cars,sort(reserve=Ture))
# sorted() 临时排序
print(sorted(cars))
# reserve(): 逆转列表元素
cars.reserve()
# 函数len(): 获取列表长度
len(cars) magicians = ['alice', 'david','carolina']
for magician in magicians:
# for 语句末尾：说明自下一句开始执行循环。
# for循环只对for语句后缩进行生效。
print(magician) # 函数range()：提供数值范围，可以指定步长
# 函数list()：提供列表
# 函数min(),max(),sum()用于处理数值列表
numbers = list(range(1,6))
print(numbers)
squares = []
for value in range(1,11,2):
squares.append(value**2)
print(squares)
# 列表解析:
squares = [value**2 for value in range(1,11,2)]
print(squares)
# 整除题: 列出30 以内可以被3整除的数字
squares = [value*3 for value in range(1,11)]
print(squares)players = ['chares', 'martina', 'michael', 'flore', 'eli']
#切片
print(players[0:4])
#从头切片,切片时终止发生在终止索引之前，即终止索引的值不包括在所切的片内
print(players[:4])
#切片至尾部
print(players[2:])
# 从倒数位置切片
print(players[-3:])
# 遍历列表: 使用for循环
print("here are my first three players on my team")
for player in players[:3]:
print(player.title())
# 复制列表：注意区分列表与变量
my_foods = ['pizza', 'falafel', 'carrot cake']
friend_foods = my_foods[:] #复制列表
#friend_foods = my_food :复制变量, 即复制变量指向的列表
my_foods.append('cannoli')
friend_foods.append('ice cream')
print(my_foods)
print(friends_foods)dimensions = (200,50)# 使用小括号定义元组
print("originan dimensions:")
for dimension in dimensions:
print(dimension)
# 对元组变量重新赋值
dimensions = (250, 100)
print("\nModified dimensions:")
for dimension in dimensions:
print(dimension)car = "Audi"
# 条件检查
car == "bwm"
car.lower() == "audi"
if
elif
else字典的值：数字，字符串，列表，字典
alien_0 = {'color' : 'green' , 'points' : 5}
#访问字典的值
new_points = alien_0['points']
print("you just earned" + str(new_points) + "points!")
#添加键值对
alien_0['x_position'] = 0
alien_0['y_position'] = 25
# 在空列表中添加
alien_1 = {}
alien_1['color'] = sliver
alien_1['points'] =5
#修改字典中的值
alien_0['color'] = 'yellow'
# 删除键值对：del语句
del alien_0['pionts'] # 遍历键值对
user_0 = {
'username' : 'ali'
'first' : 'en'
'last' : 'fe'
}
for key, value in user_0.item():
#.item()方法默认可以声明任意两个变量分别用以储存键和值
print("\n Key:" + key)
print("Value:" + value)
#遍历键： 方法.keys(), 函数sorted()（排序）
#遍历值：.values()，函数set()（剔除重复项）# 字典中嵌套列表
favorite_languages = {
'jen': ['python', 'ruby'],
'sarah': ['c'],
'edward': ['ruby', 'go'],
'phil': ['python', 'haskell'],
}
for name,languages in favorite_languages.item():
#将值对应的列表储存在变量中
print("\n" + name.title() + "'s favorite languages are:")
for language in languages:#通过循环语句逐次取出列表中的值
print("\t" + language.title())
# 字典嵌套字典
users = {
'aeinstein': {
'first': 'albert',
'last': 'einstein',
'location': 'princeton',
},
'mcurie': {
'first': 'marie',
'last': 'curie',
'location': 'paris',
}
}
for username,user_info in user.item():# 将代表字典的值储存在变量中
print("\nUsername:" + username)
Full_name = user_info['first'] + user_info['last']
#直接调用代表第一层字典的值的变量的值（第二层字典的值）
locarion = user_info['location']
print("\tFULL NAME:" + Full_name.title())
print("\tLOCATION:" + locarion.title())prompt = "\nTell me something, and I will repeat it back to you."
prompt += "\nEnter 'quit' to end the program."
message = ""
while message != "quit":
message = input(prompt)
if message != "quit":
#这里嵌套了一个条件语句，利用内嵌的条件决定是否终结循环
print(message)class Dog():
"""类的说明"""
#__init__(self)是必须的，是类的本征初始量
def __init__(self,name,age):
self.name = name
self.age = age
def sit(self):
print(self.name.title() + "is now sitting.")
def roll_over(self):
print(self.name.title() + "rolled over!")
# 通过调用类并将之储存在一个变量中使之成为一个实例
my_dog = Dog('whille',16)
# 调用定义在类中的变量（这里是类的属性）
print(my_dog.name.title())
# 调用定义在类中的函数
my_dog.roll_over()from random import choice
class RandomWalk():
"""一个生成随机漫步数据的类"""
def __init__(self, num_points=5000):
"""初始化随机漫步的属性"""
self.num_points = num_points
# 所有随机漫步都始于(0, 0)
self.x_values = [0]
self.y_values = [0]
def fill_walk(self):
"""计算随机漫步包含的所有点"""
# 不断漫步，直到列表达到指定的长度
while len(self.x_values) < self.num_points:
# 决定前进方向以及沿这个方向前进的距离
x_direction = choice([1, -1])
x_distance = choice([0, 1, 2, 3, 4])
x_step = x_direction * x_distance
y_direction = choice([1, -1])
y_distance = choice([0, 1, 2, 3, 4])
y_step = y_direction * y_distance
# 拒绝原地踏步
if x_step == 0 and y_step == 0:
continue
# 计算下一个点的x和y值
next_x = self.x_values[-1] + x_step
next_y = self.y_values[-1] + y_step
self.x_values.append(next_x)
self.y_values.append(next_y)import matplotlib.pyplot as pt
from random_walk import RandomWalk
while True:
rw = RandomWalk(100000)
rw.fill_walk()
#设置绘图窗口
pt.figure(figsize=(20,12))
#隐藏坐标轴(过时的写法)
#pt.axes().xaxis().set_visible(False)
#pt.axes().set_visible(False)
point_numbers = list(range(rw.num_points))
pt.scatter(rw.x_values, rw.y_values, c = point_numbers, cmap = pt.cm.Blues,
s=15)
#突出起点和终点
pt.scatter(0,0, c='green', edgecolor='none',s=100)
pt.scatter(rw.x_values[-1],rw.y_values[-1],c='red',edgecolor='none',
s=100)
pt.axis('off')
pt.show()
keep_running = input("Make another walk?(y/n)")
if keep_running == 'n':
breakfrom die import Die
import pygal
# D6实例
die = Die()
#掷骰子，将结果存在列表中
results = []
for roll_num in range(1000):
result = str(die.roll())
results.append(result)
#分析数值
frequencies = []
for value in range(1,die.num_sides+1):
frequency = results.count(str(value))
frequencies.append(frequency)
print(frequencies)
#直方图
hist = pygal.Bar()
hist.title = "Results of rooling one D6 1000 times"
hist.x_lables = ['1','2','3','4','5','6']
hist.x_title = "Results"
hist.y_title = "Frequency of Result"
hist.add('D6',frequencies)
hist.render_to_file('die_visual.svg')import csv
from datetime import datetime
from matplotlib import pyplot as plt
filename = 'sitka_weather_07-2014.csv'
with open(filename) as f:
reader = csv.reader(f)
header_row = next(reader)
dates,highs =[],[]
for row in reader:
current_date = datetime.strptime(row[0],
"%Y-%m-%d")
dates.append(current_date)
highs.append(int(row[1]))
#for index, colum_header in enumerate(header_row):
#enumerate()将header_row 整理成具有索引的形式
# print(index, colum_header)
#绘图及图形格式
fig = plt.figure(dpi=128, figsize=(20,12))
plt.plot(dates,highs,c = 'red')
plt.title("Daily high temperature, July 2014", fontsize=24)
plt.xlabel('',fontsize=16)
fig.autofmt_xdate()
plt.ylabel("Temperature(F)", fontsize=16)
plt.tick_params(axis='both', which='major', labelsize=16)
plt.show()
import json
import pygal
import pygal_maps_world.maps
from pygal.style import LightColorizedStyle as LCS, RotateStyle as RS
from pygal_maps_world.i18n import COUNTRIES
def get_country_code(countryname):
for code, name in COUNTRIES.items():
if name == countryname:
return code
return None
filename = "population_data.json"
with open(filename) as f:
pop_data = json.load(f)
cc_populations = {}
for pop_dict in pop_data:
if pop_dict['Year'] == '2010':
country_name = pop_dict['Country Name']
population = int(float(pop_dict['Value']))
code = get_country_code(country_name)
if code:
cc_populations[code] = population
cc_pops_1, cc_pops_2, cc_pops_3 = {}, {}, {}
for cc, pop in cc_populations.items():
if pop < 1000000:
cc_pops_1[cc] = pop
elif pop < 100000000:
cc_pops_2[cc] = pop
else:
cc_pops_3[cc] = pop
wm = pygal_maps_world.maps.World()
wm_style = RS('#336699',base_style=LCS)
wm.title = "World Poplation in 2010, by country"
wm.add('0-1m', cc_pops_1)
wm.add('1m-100m', cc_pops_2)
wm.add('>100m', cc_pops_3)
wm.render_to_file('World Poplation.svg')