author：headsen chen
date ： 2018-05-31 17:59:04
notice：本文素材来自于：<< 笨方法学python >> 这本书,由本人重新整理如下：
1.print的用法：
[root@localhost py]# cat print1.py #!/usr/bin/env python print "Hellow world" print "Hello Again" print "I like typing this." print "This is fun." print "Yay! Printing." print "I\'d much rather you 'not'." print "I 'said' do not touch this." [root@localhost py]# /py/print1.py Hellow world Hello Again I like typing this. This is fun. Yay! Printing. I'd much rather you 'not'. I 'said' do not touch this.
习题 2: 注释和井号
[root@localhost py]# cat print2.py #!/usr/bin/env python # ou bbbbbbbbbb dddddd print "This is will run." # print 4444444444 [root@localhost py]# /py/print2.py This is will run.
习题 3: 数字和数学计算
名字如下：
+ plus 加号
- minus 减号
/ slash 斜杠
* asterisk 星号
% percent 百分号
< less-than 小于号
> greater-than 大于号
<= less-than-equal 小于等于号
>= greater-than-equal 大于等于号
[root@localhost py]# cat cal.py #!/usr/bin/env python print "I will now count my chickens:" print "Hens",25 + 30 /6 print 'Roosters',100-25*3/4 print 'Now I will count the eggs:' print 2+4+1 -4+6%2-1/4 +6 print "Is it true that 3+2 < 5-7?" print 3+2 < 5-7 print "What is 3+2?",3+2 print "what is 5-7?",5-7 print "oh,that is why it\'s False" print "How about some more." print "Is it greater?",5> -2 print "Is it greater or equal?",5>=-2 print "Is it less or equal?",5 <= -2
[root@localhost py]# python cal.py I will now count my chickens: Hens 30 Roosters 82 Now I will count the eggs: 9 Is it true that 3+2 < 5-7? False What is 3+2? 5 what is 5-7? -2 oh,that is why it's False How about some more. Is it greater? True Is it greater or equal? True Is it less or equal? False
习题 4: 变量(variable)和命名
[root@localhost py]# cat var.py #!/usr/bin/env python cars = 100 space_in_a_car = 4.0 drivers = 30 passengers = 90 cars_not_driven = cars - drivers cars_driven = drivers carpool_capacity = cars_driven * space_in_a_car average_passengers_per_car = passengers / cars_driven print "There are ",cars,"cars available." print "There are only",cars_not_driven,"empty cars today." print "We can transport",carpool_capacity,"people today." print "We have",passengers,"to carpool today." print "We need to put about",average_passengers_per_car,"in each car." [root@localhost py]# python var.py There are 100 cars available. There are only 70 empty cars today. We can transport 120.0 people today. We have 90 to carpool today. We need to put about 3 in each car.
习题 5: 更多的变量
[root@localhost py]# cat var2.py #!/usr/bin/env python my_name = 'Zed A. Shaw' my_age = 35 # not a lie my_weight = 174 # inches my_height = 75 # lbs my_eyes = 'blue' my_teech = 'white' my_hair = 'brown' print "Let\'s talk about %s." % my_name print "He\'s %d inches tall." % my_height print "He\'s %d pounds heavy." % my_weight print "Actually that\'s not too heavy." print "He\'s got %s eyes and %s hair." %(my_eyes,my_hair) print "His teeth are usually %s depending on the coffee." % my_teech [root@localhost py]# python var2.py Let's talk about Zed A. Shaw. He's 75 inches tall. He's 174 pounds heavy. Actually that's not too heavy. He's got blue eyes and brown hair. His teeth are usually white depending on the coffee.
习题 6: 字符串(string)和文本
[root@localhost py]# cat string.py
#!/usr/bin/env python
x = "There are %d types of people." %10
binary = 'binary'
do_not = "don\'t"
y = "Those who know %s and those who %s." % (binary,do_not)
print x
print y
print "I said: %r." %x
print "I said: '%s'." %y
joke_evaluation = "Isn\'t that joke so funny?! %r"
hilarious = False
print joke_evaluation % hilarious
w = "This is the left side of ..."
e = 'a string with right side.'
print w + e
[root@localhost py]# python string.py
There are 10 types of people.
Those who know binary and those who don't.
I said: 'There are 10 types of people.'.
I said: 'Those who know binary and those who don't.'.
Isn't that joke so funny?! False
This is the left side of ...a string with right side.
习题 7: 更多打印
[root@localhost py]# cat print3.py
#!/usr/bin/env python
print "Mary had a liitle lamb."
print "Its fleece was white as %s." % 'snow'
print "Add everyone that Mary went."
print "." * 10 # what'd that do?
end1 = 'c'
end2 = 'b'
end3 = 'e'
end4 = 'e'
end5 = 's'
end6 = 'e'
end7 = 'B'
end8 = 'u'
end9 = 'r'
end10 = 'g'
end11 = 'e'
end12 = 'r'
# what that comma at the end,try removing it to see what happens.
print end1 + end2 + end3+ end4 + end5 + end6
print end7 +end8 +end9 +end10 + end11 +end12
[root@localhost py]# python print3.py
Mary had a liitle lamb.
Its fleece was white as snow.
Add everyone that Mary went.
..........
cbeese
Burger
习题 8: 打印
[root@localhost py]# cat print4.py
#!/usr/bin/env python
formatter = "%r %r %r %r"
print formatter %(1,2,3,4)
print formatter %('one','two','three','four')
print formatter %(True,False,False,True)
print formatter %(formatter,formatter,formatter,formatter)
print formatter %(
"I had this thing.",
"That you could type up right.",
"But it didn\'t sing.",
"So I said goodnight."
)
[root@localhost py]# python print4.py
1 2 3 4
'one' 'two' 'three' 'four'
True False False True
'%r %r %r %r' '%r %r %r %r' '%r %r %r %r' '%r %r %r %r'
'I had this thing.' 'That you could type up right.' "But it didn't sing." 'So I said goodnight.'
习题 9: 打印
[root@localhost py]# cat print5.py
#!/usr/bin/env python
days = "Mon Tue Wed Thu Fri Sat Sun"
months = "Jan\nFeb\nMar\nApr\nMay\nJun\nJul\nAug"
print "Here are the days: ",days
print "Here are the months: ",months
print """
There\'s something going on here.
With the three double-quotes.
We\'ll be able to type as much as we like.
Even 4 lines if we want,or 5,or 6.
"""
[root@localhost py]# python print5.py
Here are the days: Mon Tue Wed Thu Fri Sat Sun
Here are the months: Jan
Feb
Mar
Apr
May
Jun
Jul
Aug
There's something going on here.
With the three double-quotes.
We'll be able to type as much as we like.
Even 4 lines if we want,or 5,or 6.
习题10：转义和三引号用法
"I am 6'2\" tall." # 将字符串中的双引号转义
'I am 6\'2" tall.' # 将字符串种的单引号转义
[root@localhost py]# cat print6.py
#!/usr/bin/env python
tabby_cat = "\tI\'m tabbed in."
persian_cat = "I\'m split\non a line."
backslash_cat = "I\'m \\ a \\ cat."
fat_cat = """
I\'ll do a list:
\t* Cat food
\t* Fishies
"""
print tabby_cat
print persian_cat
print backslash_cat
print fat_cat
[root@localhost py]# python print6.py
I'm tabbed in.
I'm split
on a line.
I'm \ a \ cat.
I'll do a list:
* Cat food
* Fishies
习题 11: 提问和交互式输入
[root@localhost py]# cat input.py
#!/usr/bin/env python
print "How old are you?",
age = raw_input()
print "How tall are you?",
height = raw_input()
print "How much do you weight?",
weight = raw_input()
print "So,you\'re %r old,%r tall and %r heavy."%(age,height,weight)
[root@localhost py]# python input.py
How old are you? 35
How tall are you? 455
How much do you weight? 233
So,you're '35' old,'455' tall and '233' heavy.
习题 12: 带提示的raw_input()
[root@localhost py]# cat input2.py
#!/usr/bin/env python
age = raw_input("How old are you? ")
height = raw_input("How tall are you? ")
weight = raw_input("How much do you weight? ")
print "So,you\'re %r old,%r tall and %r heavy."%(age,height,weight)
[root@localhost py]# python input2.py
How old are you? 34
How tall are you? 544
How much do you weight? 2342
So,you're '34' old,'544' tall and '2342' heavy.
习题 13: 带参数的python文件和导入模组 ：每个参数赋予一个变量名： script, first, second
[root@localhost py]# cat argv.py
#!/usr/bin/env python
from sys import argv
script,first,second,third = argv
print "The script is called: ",script
print "Your first variable is: ",first
print "Your second variavle is: ",second
print "Your third variavle is: ",third
[root@localhost py]# python argv.py 1 2 3
The script is called: argv.py
Your first variable is: 1
Your second variavle is: 2
Your third variavle is: 3
[root@localhost py]# python argv.py cheese apples bread
The script is called: argv.py
Your first variable is: cheese
Your second variavle is: apples
Your third variavle is: bread
习题14 带参数的python文件2
[root@localhost py]# cat argv2.py
#!/usr/bin/env python
from sys import argv
script,user_name = argv
prompt = '>'
print "Hi %s,I\'m the %s script." %(user_name,script)
print "I\'d like to ask you a few questions."
print "Do you like me %s" % user_name
likes = raw_input(prompt)
print "Where do you like %s?" % user_name
lives = raw_input(prompt)
print "What kind of computer do you have?"
computer = raw_input(prompt)
print """
Alright,so you said %r about liking me.
You live in %r. Not sure where that is.
And you have a %r computer. Nice.
""" %(likes,lives,computer)
[root@localhost py]# python argv2.py mary
Hi mary,I'm the argv2.py script.
I'd like to ask you a few questions.
Do you like me mary
>no
Where do you like mary?
>bike
What kind of computer do you have?
>aus
Alright,so you said 'no' about liking me.
You live in 'bike'. Not sure where that is.
And you have a 'aus' computer. Nice.
习题15: 文件的打开和读取
[root@localhost py]# cat file.py
#!/usr/bin/env python
from sys import argv
script,filename = argv
txt = open(filename)
print "Here\' your file %r: " %filename
print txt.read()
print "Type the file name again: "
file_again = raw_input(">")
txt_again = open(file_again)
print txt_again.read()
[root@localhost py]# python file.py ex15_sample.txt
Here' your file 'ex15_sample.txt':
This is stuff I typed into a file.
It is really cool stuff.
Lots and lots of fun to have in here.
Type the file name again:
>ex15_sample.txt
This is stuff I typed into a file.
It is really cool stuff.
Lots and lots of fun to have in here.
[root@localhost py]#
习题 16: 读写文件
应该记住的命令如下：
close – 关闭文件。跟你编辑器的 文件->保存.. 一个意思。
read – 读取文件内容。你可以把结果赋给一个变量。
readline – 读取文本文件中的一行。
truncate – 清空文件，请小心使用该命令。
write(stuff) – 将 stuff 写入文件。
[root@localhost py]# cat file2.py
#!/usr/bin/env python
from sys import argv
script,filename = argv
print "We\'re going to erase %r." %filename
print "If you don\'t want that,hit CTRL-C(^C)."
print "If you do want that,hit RETURN."
raw_input("?")
print "Openning the file ..."
target = open(filename,'w')
print "Truncating the file.Goodby!"
target.truncate()
print "Now I\'m going to ask you for three lines."
line1 = raw_input("line 1: ")
line2 = raw_input("line 2: ")
line3 = raw_input("line 3: ")
print "I\'m going to write these to the file."
target.write(line1)
target.write("\n")
target.write(line2)
target.write("\n")
target.write(line3)
target.write("\n")
print "And finally,we close it."
target.close()
运行该脚本：随便取个文件名：bb.txt
[root@localhost py]# python file2.py bb.txt
We're going to erase 'bb.txt'.
If you don't want that,hit CTRL-C(^C).
If you do want that,hit RETURN.
?
Openning the file ...
Truncating the file.Goodby!
Now I'm going to ask you for three lines.
line 1: 1111111111
line 2: 2222222222
line 3: 3333333333
I'm going to write these to the file.
And finally,we close it.
检验：新生成的bb.txt的文件内容是否为写入的内容
[root@localhost py]# cat bb.txt
1111111111
2222222222
3333333333