1、 Two ways to execute Python scripts
Interactive mode: command line
Under the Windows operating system, the shortcut key cmd, enter "python" to start the interactive python interpreter.
File format: python file
2、 Briefly describe the relationship between bits and bytes
A binary bit is the smallest unit of representation in the computer.
A byte is the smallest storage unit in a computer.
Binary bits=8bits=1Byte=1 byte
3、 Briefly describe the relationship between ascii, unicode, utf-8, gbk
The United States has formulated a set of character codes, and unified regulations on the relationship between English characters and binary bits. This is called ASCII code.
Unicode is a character encoding scheme developed by an international organization that can accommodate all characters and symbols in the world. Include all the symbols in the world. Each symbol is given a unique code, then the garbled problem will disappear. This is Unicode, as its name implies, this is an encoding of all symbols.
The popularity of the Internet strongly requires a unified coding method. UTF-8 is the most widely used implementation of Unicode on the Internet. One of the biggest features of UTF-8 is that it is a variable length encoding method. It can use 1 to 4 bytes to represent a symbol, and the byte length varies according to different symbols. In UTF-8, English occupies one byte, and Chinese occupies 3 bytes.
GBK: Chinese character national standard extension code, which basically uses all the Chinese characters and code points of the original GB2312-80, and covers all the Chinese characters in the original Unicode 20902. A total of 883 symbols, 21003 Chinese characters and 1894 characters are provided. Code point. Since GBK also covers all CJK Chinese characters in Unicode, it can also correspond to Unicode one-to-one. Windows default encoding GBK, Chinese occupies 2 bytes.
4、 Please write the number of digits coded with utf-8 and gbk for "Li Jie"
In utf-8, one English occupies one byte, one Chinese occupies 3 bytes, and "Li Jie" occupies 6 bytes here.
In GBK, a Chinese character occupies 2 characters, where "Li Jie" occupies 4 characters.
**5、 What are the use of Pyhton single-line comments and multi-line comments? **
Python single-line comments use #, and multi-line comments use triple quotation marks "''".
**6、 What are the precautions for declaring variables? **
Declare variables need to be assigned first. Variable names can contain letters, numbers, and underscore _. Variables cannot start with a number.
7、 How to check the address of a variable in memory?
id (variable name) #View the memory address.
**8、 What is the function of the automatically generated .pyc file when executing a Python program? **
Python saves bytecode in this way as an optimization for startup speed. The next time you run the program, if you haven't modified the source code after saving the bytecode last time, Python will load the .pyc file and skip the compilation step. When Python must be recompiled, it will automatically check the timestamp of the source file and the bytecode file: if you save the source code again, the bytecode will be automatically recreated the next time the program is run.
9、 write the code
**a. Realize that the user enters the user name and password. When the user name is seven and the password is 123, the login is successful, otherwise the login fails! **
username=input("username:")
passwd=input("passwd:")if username=="seven" and passwd=="123":print("login successful!")else:print("Login failed!")
b. Implement the user to enter the user name and password. When the user name is seven and the password is 123, the login is successful, otherwise the login fails. If it fails, it is allowed to enter three times repeatedly
count=0while True:
username =input("username:")
passwd =input("passwd:")if username=="seven" and passwd=="123":print("login successful!")break
count +=1if count==3:print("Login failed!")break
10、 write the code
a. Use the while loop to achieve the sum of output 2-3 + 4-5 + 6 ... + 100
i=2
total_1=0
total_2=0while i<=100:if i%2==0:
total_1+=i
else:
total_2+=-i
i+=1
total=total_1+total_2
print(total)
b. Use for loop and range to realize the sum of output 1-2 + 3-4 + 5-6 ... + 99
total_1=0
total_2=0for i inrange(100):if i%2==1:
total_1+=i
else:
total_2+=-i
total=total_1+total_2
print(total)
c. Use while loop to achieve output 1, 2, 3, 4, 5, 7, 8, 9, 11, 12
i=1while True:if i>=1 and i<=5:print(i)if i>=7 and i<=9:print(i)if i==11 or i==12:print(i)
i+=1
d. Use a while loop to output all odd numbers within 1-100
i=1while i<=100:if i%2==1:print(i)
i+=1
e. Use the while loop to output all even numbers within 1-100
i=1while i<=100:if i%2==0:print(i)
i+=1
11、 Write the binary representation of the numbers 5, 10, 32, and 7 respectively
Number 5: 00000101
Number 10: 00001010
Number 32: 00100000
Number 7: 00000111
12、 Briefly describe the relationship between the object and the class (anaphorically available)
A class is a collection of objects with the same data structure (attribute) and the same operation function (behavior). An object is an instance that conforms to a certain class.
**13、 There are the following two variables, please briefly describe the relationship between n1 and n2? **
n1 = 123
n2 = 123
n1 and n2 use the same memory address
Python internal optimization: The assignment variables between -5 and 157 are all the same address
**14、 There are the following two variables, please briefly describe the relationship between n1 and n2? **
n1 = 123456
n2 = 123456
n1 and n2 use different memory addresses
Python internal optimization: The assignment variables between -5 and 157 are all the same address
**15、 There are the following two variables, please briefly describe the relationship between n1 and n2? **
n1 = 123456
n2 = n1
Use the same memory address, but the variable names are different
**16、 If there is a variable n1 = 5, please use the method provided by int to get the minimum number of binary bits that the variable can be represented by? **
3 Two binary digits, 00000101
**17、 What are the Boolean values? **
True and False
0, 1 in binary. In many cases, 0 is considered False, and all non-zeros are considered True.
18、 Read the code, please write the execution result
a = "alex"
b = a.capitalize()
print(a)
print(b)
**Please write the output result: **alex Alex #capitalize() capitalize the first letter and lowercase the other letters
19、 Write the code, there are the following variables, please implement each function as required
name = " aleX"
a. Remove the spaces on both sides of the value corresponding to the name variable, and enter the removed content
name=" aleX"print(name.strip())
b. Determine whether the value corresponding to the name variable starts with "al" and output the result
name=" aleX"if name[0:2]=="al":print("True")else:print("False")
Output False
Method 2: print(name.startswith("al")) False
c. Determine whether the value corresponding to the name variable ends with "X", and output the result
name=" aleX"if name[-1]=="X":print("True")else:print("False")
Output True
Method 2: print(name.endswith("X")) True
d.Replace "l" with "p" in the value corresponding to the name variable and output the result
name=" aleX"print(name.replace("l","p"))
Output: apeX
**e. Split the value corresponding to the name variable according to "l" and output the result. **
name=" aleX"print(name.split("l"))
Output:[' a','eX']
**f. Excuse me, what type of value is obtained after dividing e in the previous question? **
name.split("l") #Split the characters into a list with "l"
g. Capitalize the value corresponding to the name variable and output the result
name=" aleX"print(name.upper())
Output: ALEX
h. Change the value corresponding to the name variable to lowercase and output the result
name=" aleX"print(name.lower())
Output: alex
**i. Please output the second character of the value corresponding to the name variable? **
name=" aleX"print(name[1])
Output: a
**j. Please output the first 3 characters of the value corresponding to the name variable? **
name=" aleX"print(name[0:3])
Output: al
**k. Please output the last 2 characters of the value corresponding to the name variable? **
name=" aleX"print(name[-2:])
Output: eX
**l. Please output the index position of "e" in the value corresponding to the name variable? **
name=" aleX"print(name.index("e"))
Output: 3
**20、 Is the string iterable? If possible, please use for loop for each element? **
name="aleX"for i inrange(len(name)):print(name[i])
**21、 Please use code to achieve: Use underscores to splice each element of the list into a string, li = ['alex','eric','rain'] **
li=['alex','eric','rain']print('_'.join(li))
Output: alex_eric_rain
li ＝ ['alex', 'eric', 'rain']
li=['alex','eric','rain']print(len(li))
Output: 3
li=['alex','eric','rain']
li.append('seven')print(li)
Output:['alex','eric','rain','seven']
li=['alex','eric','rain']
li.insert(0,'tony')print(li)
Output:['tony','alex','eric','rain']
li=['alex','eric','rain']
li[1]="kelly"print(li)
Output:['alex','kelly','rain']
li=['alex','eric','rain']
li.pop(1)print(li)
Output:['alex','rain']
li=['alex','eric','rain']
li.remove("eric")print(li)
Output:['alex','rain']
li=['alex','eric','rain']print(li[1])
li.pop(1)print(li)
Output: eric
[' alex','rain']
li=['alex','eric','rain']
li.pop(2)print(li)
Output:['alex','eric']
li=['tony','alex','eric','rain','seven']
del li[1:4]print(li)
Output:['tony','seven']
li=['tony','alex','eric','rain','seven']
li.reverse()print(li)
Output:['seven','rain','eric','alex','tony']
li=['tony','alex','eric','rain','seven']for i inrange(len(li)):print(li.index(li[i]),li[i])
Output: 0 tony
1 alex
2 eric
3 rain
4 seven
li=['alex','eric','rain']for i,j inenumerate(li):print(i+100,j)
Output: 100 alex
101 eric
102 rain
li=['tony','alex','eric','rain','seven']for i inrange(len(li)):print(li[i])
Output: tony
alex
eric
rain
seven
li =["hello",'seven',["mon",["h","kelly"],'all'],123,446]print(li[2][1][1])
li =["hello",'seven',["mon",["h","kelly"],'all'],123,446]print(li[2][2].upper())
tu =('alex','eric','rain')print(len(tu))
Output: 3
tu =('alex','eric','rain')print(tu[1])
Output: eric
tu =('alex','eric','rain')print(tu[0:2])Output:('alex','eric')
tu =('alex','eric','rain')for i inrange(len(tu)):print(tu[i])
Output: alex
eric
rain
e. Please use for, len, range to output the index of the tuple
tu =('alex','eric','rain')for i inrange(len(tu)):print(i,tu[i])
Output: 0 alex
1 eric
2 rain
tu =('alex','eric','rain')for i,j inenumerate(tu):print(i+10,j)
Output: 10 alex
11 eric
12 rain
The same as the list, but the tuple is only readable and cannot be modified.
It cannot be modified. The tuple clearly stipulates that the stored data should not be modified. It can be modified after the list is forcibly changed.
k2 is a list and can be modified.
tu =("alex",[11,22,{"k1":'v1',"k2":["age","name"],"k3":(11,22,33)},44])
tu[1][2]["k2"].append("seven")print(tu)Output:('alex',[11,22,{'k1':'v1','k2':['age','name','seven'],'k3':(11,22,33)},44])
k3 is a tuple and cannot be modified. The following is mandatory modification:
tu =("alex",[11,22,{"k1":'v1',"k2":["age","name"],"k3":(11,22,33)},44])
k3 is the key in the dictionary in the tuple part
tu[1][3]["k3"]=list(tu[1][3]["k3"])
tu[1][3]["k3"].append("seven")
tu[1][3]["k3"]=tuple(tu[1][3]["k3"])print(tu)
dic ={'k1':"v1","k2":"v2","k3":[11,22,33]}for key in dic.keys():print(key)
Output: k1
k2
k3
dic ={'k1':"v1","k2":"v2","k3":[11,22,33]}for value in dic.values():print(value)
Output: v1
v2
[11,22,33]
dic ={'k1':"v1","k2":"v2","k3":[11,22,33]}for i ,j in dic.items():print(i,j)
Output: k1 v1
k2 v2
k3 [11,22,33]
dic ={'k1':"v1","k2":"v2","k3":[11,22,33]}
dic["k4"]="v4"print(dic)
Output:{'k1':'v1','k2':'v2','k3':[11,22,33],'k4':'v4'}
dic ={'k1':"v1","k2":"v2","k3":[11,22,33]}
dic["k1"]="alex"print(dic)
Output:{'k1':'alex','k2':'v2','k3':[11,22,33]}
dic ={'k1':"v1","k2":"v2","k3":[11,22,33]}
dic["k3"].append(44)print(dic)
Output:{'k1':'v1','k2':'v2','k3':[11,22,33,44]}
dic ={'k1':"v1","k2":"v2","k3":[11,22,33]}
dic["k3"].insert(0,18)print(dic)
Output:{'k1':'v1','k2':'v2','k3':[18,11,22,33]}
s="alex"
s=list(s)print(type(s))
Output:<class'list'>
s="alex"
s=tuple(s)print(type(s))
Output:<class'tuple'>
li=["alex","seven"]
li=tuple(li)print(type(li))
Output:<class'tuple'>
tu =('Alex',"seven")
tu=list(tu)print(type(tu))
Output:<class'tuple'>
d.Will list li=["alex","seven"]Converted into a dictionary and the key of the dictionary starts to increase backwards from 10
li =["alex","seven"]
dir={}
a=10for i in li:
dir[a]=i
a+=1print(dir)
Output:{10:'alex',11:'seven'}
n="old boys"
n1=n.encode("utf-8")print(n1)
n2=n1.decode("utf-8")print(n2)
Output: b'\xe8\x80\x81\xe7\x94\xb7\xe5\xad\xa9'
old boys
n="old boys"
n1=n.encode("gbk")print(n1)
n2=n1.decode("gbk")print(n2)
Output: b'\xc0\xcf\xc4\xd0\xba\xa2'
old boys
More coding issues link: http://www.cnblogs.com/yuanchenqi/articles/5956943.html
sum=0for i inrange(101):
sum+=i
print(sum)
Output: 5050
tu=[11,22,33,44,55,66,77,88,99,90]
n1=[]
n2=[]
dir={}for i in tu:if i >66:
n1.append(i)else:
n2.append(i)
dir["k1"]=n1
dir["k2"]=n2
print(dir)
Output:{'k1':[77,88,99,90],'k2':[11,22,33,44,55,66]}
goods =[{"name":"computer","price":1999},{"name":"mouse","price":10},{"name":"yacht","price":20},{"name":"beauty","price":998},]
goods_cart=[]while True:
salary=input("input your salary:")if salary.isdigit():
salary=int(salary)while True:print("Numbering","commodity","\t","price")for i inrange(len(goods)):print(i+1,"\t",goods[i]["name"],"\t",goods[i]["price"])
choice=input(">>:").strip()if choice.isdigit():
choice=int(choice)if choice>0 and choice<=(len(goods)-1):if salary-goods[choice-1]["price"]>=0:
salary-=goods[choice-1]["price"]
goods_cart.append(goods[choice])print(goods[choice-1]["name"],"Add to shopping cart and purchase successfully","Remaining balance",salary)else:print("Not enough balance to purchase,Not bad",goods[choice-1]["price"]-salary)if choice=="q":print("The product you bought is",goods_cart,"Left",salary,"yuan")breakelse:print("The product you entered does not exist!")breakprint("Welcome next time!")
Specific notes: link http://www.cnblogs.com/xuyaping/p/6639850.html
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