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