Python入门教程

Python 入门教程1 ---- Python Syntax

1 Python是一个高效的语言，读和写的操作都是很简单的，就像普通的英语一样

2 Python是一个解释执行的语言，我们不需要去编译，我们只要写出代码即可运行

3 Python是一个面向对象的语言，在Python里面一切皆对象

4 Python是一门很有趣的语言

5 变量：一个变量就是一个单词，只有一个单一的值

练习：设置一个变量my_variable，值设置为10

[cpp]

#Write your code below!

my_variable = 10

3 第三节

1 Python里面有三种数据类型 interage , floats , booleans

2 Python是一个区分大小写的语言

3 练习

1 把变量my_int 值设置为7

2 把变量my_float值设置为1.23

3 把变量my_bool值设置为true

[python]

#Set the variables to the values listed in the instructions!

my_int = 7

my_float = 1.23

my_bool = True

6 Python的变量可以随时进行覆盖

2 练习：my_int的值从7改为3，并打印出my_int

[python]

#my_int is set to 7 below. What do you think

#will happen if we reset it to 3 and print the result? my_int = 7

#Change the value of my_int to 3 on line 8!

my_int = 3

#Here's some code that will print my_int to the console: #The print keyword will be covered in detail soon!

print my_int

7 Pyhton的声明和英语很像

8 Python里面声明利用空格在分开

3 练习：查看以下代码的错误

[python]

def spam():

eggs = 12

return eggs

print spam()

9 Python中的空格是指正确的缩进

2 练习：改正上一节中的错误

[python]

def spam():

eggs = 12

return eggs

print spam()

10 Python是一种解释执行的语言，只要你写完即可立即运行

2 练习：设置变量spam的只为True，eggs的值为False [python]

spam = True

eggs = False

11 Python的注释是通过“#”来实现的，并不影响代码的实现

2 练习：给下面的代码加上一行注释

[python]

#this is a comments for Python

mysterious_variable = 42

12 Python的多行注释是通过“""" """ ”来实现的

2 练习：把下面的代码加上多行

[python]

"""

this is a Python course

"""

a = 5

13 Python有6种算术运算符+,-,*,/,**(幂),%

2 练习：把变量count_to设置为1+2

[python]

#Set count_to equal to 1 plus 2 on line 3!

count_to = 1+2

print count_to

14 Python里面求x^m，写成x**m

2 练习：利用幂运算，把eggs的值设置为100 [python]

#Set eggs equal to 100 using exponentiation on line 3! eggs = 10**2

print eggs

1 练习：

1 写一行注释

2 把变量monty设置为True

3 把变量python值设置为1.234

4 把monty_python的值设置为python的平方[python]

#this is a Python

monty = True

python = 1.234

monty_python = python**2

Python 入门教程2 ---- Tip Calculator

1 把变量meal的值设置为44.50

[python]

#Assign the variable meal the value 44.50 on line 3!

meal = 44.50

1 把变量tax的值设置为6.75%

[python]

meal = 44.50

tax = 6.75/100

1 设置tip的值为15%

[python]

#You're almost there! Assign the tip variable on line 5.

meal = 44.50

tax = 0.0675

tip = 0.15

1 把变量meal的值设置为meal+meal*tax

[python]

#Reassign meal on line 7!

meal = 44.50

tax = 0.0675

tip = 0.15

meal = meal+meal*tax

设置变量total的值为meal+meal*tax

[python]

#Assign the variable total on line 8!

meal = 44.50

tax = 0.0675

tip = 0.15

meal = meal + meal * tax

total = meal + meal * tip

print("%.2f" % total)

Python 入门教程3 ---- Strings and Console Output

15 Python里面还有一种好的数据类型是String

16一个String是通过'' 或者""包成的串

3 设置变量brian值为"Always look on the bright side of life!" [python]

#Set the variable brian on line 3!

brian = "Always look on the bright side of life!"

1 练习

1 把变量caesar变量设置为Graham

2 把变量praline变量设置为john

3 把变量viking变量设置为Teresa

[python]

#Assign your variables below, each on its own line!

caesar = "Graham"

praline = "John"

viking = "Teresa"

#Put your variables above this line

print caesar

print praline

print viking

17 Python是通过\来实现转义字符的

2 练习把'Help! Help! I'm being repressed!' 中的I'm中的'进行转义[python]

#The string below is broken. Fix it using the escape backslash!

'Help! Help! \'\m being repressed!'

18 我们可以使用""来避免转义字符的出现

2 练习：把变量fifth_letter设置为MONTY的第五个字符

[python]

"""

The string "PYTHON" has six characters,

numbered 0 to 5, as shown below:

+---+---+---+---+---+---+

| P | Y | T | H | O | N |

+---+---+---+---+---+---+

0 1 2 3 4 5

So if you wanted "Y", you could just type

"PYTHON"[1] (always start counting from 0!)

"""

fifth_letter = "MONTY"[4]

print fifth_letter

19 介绍String的第一种方法，len()求字符串的长度

2 练习：把变量parrot的值设置为"Norweigian Blue"，然后打印parrot的长度[python]

parrot = "Norwegian Blue"

print len(parrot)

20 介绍String的第二种方法,lower()把所有的大写字母转化为小写字母

2 练习：把parrot中的大写字母转换为小写字母并打印

[python]

parrot = "Norwegian Blue"

print parrot.lower()

21 介绍String的第三种方法,upper()把所有的大写字母转化为小写字母

2 练习：把parrot中的小写字母转换为大写字母并打印

[python]

parrot = "norwegian blue"

print parrot.upper()

第八节

1 介绍String的第四种方法,str()把非字符串转化为字符串，比如str(2)是把2转化为字符串"2"

2 练习: 设置一个变量pi值为3.14 , 把pi转化为字符串

[python]

"""Declare and assign your variable on line 4,

then call your method on line 5!"""

pi = 3.14

print str(pi)

22 主要介绍“.”的用处，比如上面的四个String的四个方法都是用到了点

2 练习: 利用“.”来使用String的变量ministry的函数len()和upper()，并打印出

[python]

ministry = "The Ministry of Silly Walks"

print len(ministry)

print ministry.upper()

23 介绍print的作用

2 练习：利用print输出字符串"Monty Python"

[python]

"""Tell Python to print "Monty Python"

to the console on line 4!"""

print "Monty Python"

1 介绍print来打印出一个变量

2 练习：把变量the_machine_goes值赋值"Ping!"，然后打印出

[python]

"""Assign the string "Ping!" to

the variable the_machine_goes on

line 5, then print it out on line 6!"""

the_machine_goes = "Ping!"

print the_machine_goes

24 介绍我们可以使用+来连接两个String

2 练习：利用+把三个字符串"Spam "和"and "和"eggs"连接起来输出

[python]

# Print the concatenation of "Spam and eggs" on line 3!

print "Spam " + "and " + "eggs"

25 介绍了str()的作用是把一个数字转化为字符串

2 练习：利用str()函数把3.14转化为字符串并输出

[python]

# Turn 3.14 into a string on line 3!

print "The value of pi is around " + str(3.14)

第十四节

1 介绍了字符串的格式化，使用%来格式化，字符串是%s

2 举例：有两个字符串，利用格式化%s来输出

[python]

string_1 = "Camelot"

string_2 = "place"

print "Let's not go to %s. 'Tis a silly %s." % (string_1, string_2)

1 回顾之前的内容

2 练习

1 设置变量my_string的值

2 打印出变量的长度

3 利用upper()函数并且打印变量值

[python]

# Write your code below, starting on line 3!

my_string = "chenguolin"

print len(my_string)

print my_string.upper()

Python 入门教程4 ---- Date and Time 26 介绍得到当前的时间datetime.now()

2 练习

1 设置变量now的值为datetime.now()

2 打印now的值

[python]

from datetime import datetime

now = datetime.now()

print now

27 介绍从datetime.now得到的信息中提取出year,month等

2 练习: 从datetime.now中得到的信息中提取出year,month,day [python]

from datetime import datetime

now = datetime.now()

print now.month

print now.day

print now.year

28 介绍把输出日期的格式转化为mm//dd//yyyy，我们利用的是+来转化

2 练习：打印当前的日期的格式为mm//dd//yyyy

[python]

from datetime import datetime

now = datetime.now()

print str(now.month)+"/"+str(now.day)+"/"+str(now.year)

29 介绍把输出的时间格式化为hh:mm:ss

2 练习：打印当前的时间的格式为hh:mm:ss

[python]

from datetime import datetime

now = datetime.now()

print str(now.hour)+":"+str(now.minute)+":"+str(now.second)

第五节

1 练习：把日期和时间两个连接起来输出

[python]

from datetime import datetime

now = datetime.now()

print str(now.month) + "/" + str(now.day) + "/" + str(now.year) + " "\ +str(now.hour) + ":" + str(now.minute) + ":" + str(now.second)

Python 入门教程 5 ---- Conditionals & Control Flow

30 介绍Python利用有6种比较的方式== , != , > , >= , < , <=

2 比较后的结果是True或者是False

3 练习

1 把bool_one的值设置为 17 < 118%100

2 把bool_two的值设置为 100 == 33*

3 + 1

3 把bool_two的值设置为 19 <= 2**4

4 把bool_four的值设置为 -22 >= -18

5 把bool_five的值设置为 99 != 98+1

[python]

#Assign True or False as appropriate on the lines below!

bool_one = 17 < 118%100

bool_two = 100 == 33*3+1

bool_three = 19 <= 2**4

bool_four = -22 >= -18

bool_five = 99 != 98+1

31 介绍了比较的两边不只是数值，也可以是两个表达式

2 练习

1 把bool_one的值设置为 20 + -10*

2 > 10%3%2

2 把bool_two的值设置为 (10+17)**2 == 3**6

3 把bool_two的值设置为 1**2**3 <= -(-(-1))

4 把bool_four的值设置为 40/20*4 >= -4**2

5 把bool_five的值设置为 100**0.5 != 6+4

[python]

# Assign True or False as appropriate on the lines below!

bool_one = 20+-10*2 > 10%3%2

bool_two = (10+17)**2 == 3**6

bool_three = 1**2**3 <= -(-(-1))

bool_four = 40/20*4 >= -4**2

bool_five = 100**0.5 != 6+4

32 介绍了Python里面还有一种数据类型是booleans，值为True或者是False

2 练习：根据题目的意思来设置右边的表达式

[python]

# Create comparative statements as appropriate on the lines below!

# Make me true!

bool_one = 1 <= 2

# Make me false!

bool_two = 1 > 2

# Make me true!

bool_three = 1 != 2

# Make me false!

bool_four = 2 > 2

# Make me true!

bool_five = 4 < 5

33 介绍了第一种连接符and的使用，只有and的两边都是True那么结果才能为True

2 练习

1 设置变量bool_one的值为False and False

2 设置变量bool_two的值为-(-(-(-2))) == -2 and 4 >= 16**0.5

3 设置变量bool_three的值为19%

4 != 300/10/10 and False

4 设置变量bool_four的值为-(1**2) < 2**0 and 10%10 <= 20-10*2

5 设置变量bool_five的值为True and True

[python]

bool_one = False and False

bool_two = -(-(-(-2))) == -2 and 4 >= 16**0.5

bool_three = 19%4 != 300/10/10 and False

bool_four = -(1**2) < 2**0 and 10%10 <= 20-10*2

bool_five = True and True

34 介绍了第二种连接符or的使用，只要or的两边有一个True那么结果才能为True

2 练习

1 设置变量bool_one的值为2**3 == 108%100 or 'Cleese' == 'King Arthur'

2 设置变量bool_two的值为True or False

3 设置变量bool_three的值为100**0.5 >= 50 or False

4 设置变量bool_four的值为True or True

5 设置变量bool_five的值为1**100 == 100**1 or 3*2*1 != 3+2+1 [python]

bool_one = 2**3 == 108%100 or 'Cleese' == 'King Arthur'

bool_two = True or False

bool_three = 100**0.5 >= 50 or False

bool_four = True or True

bool_five = 1**100 == 100**1 or 3*2*1 != 3+2+1

35 介绍第三种连接符not , 如果是not True那么结果为False，not False结果为True

2 练习

1 设置变量bool_one的值为not True

2 设置变量bool_two的值为not 3**4 < 4**3

3 设置变量bool_three的值为not 10%3 <= 10%2

4 设置变量bool_four的值为not 3**2+4**2 != 5**2

5 设置变量bool_five的值为not not False

[python]

bool_one = not True

bool_two = not 3**4 < 4**3

bool_three = not 10%3 <= 10%2

bool_four = not 3**2+4**2 != 5**2

bool_five = not not False

36 介绍了由于表达式很多所以我们经常使用()来把一些表达式括起来，这样比较具有可读性

2 练习

1 设置变量bool_one的值为False or (not True) and True

2 设置变量bool_two的值为False and (not True) or True

3 设置变量bool_three的值为True and not (False or False)

4 设置变量bool_four的值为not (not True) or False and (not True)

5 设置变量bool_five的值为False or not (True and True)

[python]

bool_one = False or (not True) and True

bool_two = False and (not True) or True

bool_three = True and not (False or False)

bool_four = not (not True) or False and (not True)

bool_five = False or not (True and True)

第八节

1 练习：请至少使用and，or，not来完成以下的练习[python]

# Use boolean expressions as appropriate on the lines below!

# Make me false!

bool_one = not ((1 and 2) or 3)

# Make me true!

bool_two = not (not((1 and 2) or 3))

# Make me false!

bool_three = not ((1 and 2) or 3)

# Make me true!

bool_four = not (not((1 and 2) or 3))

# Make me true!

bool_five = not (not((1 and 2) or 3)

37 介绍了条件语句if

38 if的格式如下, 比如

[python]

if 8 < 9:

print "Eight is less than nine!"

3 另外还有这elif 以及else，格式如下

[python]

if 8 < 9:

print "I get printed!"

elif 8 > 9:

print "I don't get printed."

else:

print "I also don't get printed!"

4 练习：设置变量response的值为'Y'

[python]

response = 'Y'

answer = "Left"

if answer == "Left":

print "This is the Verbal Abuse Room, you heap of parrot droppings!"

# Will the above print statement print to the console?

# Set response to 'Y' if you think so, and 'N' if you think not.

第十节

1 介绍了if的格式

[python]

if EXPRESSION:

# block line one

# block line two

# et cetera

2 练习：在两个函数里面加入两个加入条件语句，能够成功输出[python]

def using_control_once():

if 1 > 0:

return "Success #1"

def using_control_again():

if 1 > 0:

return "Success #2"

print using_control_once()

print using_control_again()

39 介绍了else这个条件语句

2 练习：完成函数里面else条件语句

[python]

answer = "'Tis but a scratch!"

def black_knight():

if answer == "'Tis but a scratch!":

return True

else:

return False # Make sure this returns False

def french_soldier():

if answer == "Go away, or I shall taunt you a second time!": return True

else:

return False # Make sure this returns False

40 介绍了另外一种条件语句elif的使用

2 练习：在函数里面第二行补上answer > 5，第四行补上answer < 5 , 从而完成这个函数

[python]

def greater_less_equal_5(answer):

if answer > 5:

return 1

elif answer < 5:

return -1

else:

return 0

print greater_less_equal_5(4)

print greater_less_equal_5(5)

print greater_less_equal_5(6)

第十三节

1 练习：利用之前学的比较以及连接符以及条件语句补全函数。所有的都要出现至少一次

[python]

def the_flying_circus():

# Start coding here!

if 1 < 2 and not False:

return True

elif 1 == 1 or 1 != 2 or 1 < 2 or 1 <= 2 or 1 > 2 or 1 >= 2:

return True

else:

return False