Old boy python stack s21day04 notes (data type)

Keywords: git Python Linux encoding

day04 data type (2)

Today's Content

  • list
  • tuple

Content review and supplement

  1. Computer Foundation

    • Hardware: CPU/memory/hard disk/motherboard/network card

    • Operating system:

      • linux (free / open source)
        • centos
        • ubuntu
        • redhat
      • windows
      • mac

    • Interpreter/compiler

      • Supplementary: Compiled and Explanatory Languages?

        # Compiler: After the code is written, the compiler turns it into another file, which is then handed over to the computer for execution.
# Interpretative: After writing the code to the interpreter, the interpreter will execute from the top to the next line of code: while interpreting, while executing. [Real-time translation]

    • Software (applications)

  2. Environmental Installation

    • python interpreter
      • py2
      • py3
    • Development tools: pycharm (recommendation)/text editor

  3. Python grammar

    1. Interpreter path: hello.py

      #!/usr/bin/env python

print('Hello')

      linux system application:

      • Give file executable permissions
      • ./hello.py

    2. Code

      #!/usr/bin/env python
# -*- coding:utf-8 -*-

print('Hello')
      1. Coding type
        • acsii
        • unicode
        • utf-8 / utf-16
        • gbk/gb2312
      2. Chinese Representation
        • Utf-8:3 bytes
        • gbk: 2 bytes
      3. python default interpreter encoding
        • py3: utf-8
        • py2: ascii

    3. Input and output

      • py2:
        • Input: raw_input
        • Output: print ""
      • py3:
        • Input:input
        • Output: print()

    4. data type

      1. int

        • There are int/long in py2 and int in py3.
        • Forced Conversion: int(''76')
        • Division: py2 (one more line of code) and py3 (normal)

      2. bool

        • True/False (other languages: true/false)
        • Other types of False in particular: 0 and ""

      3. str

        • Unique function

          • upper/lower

          • replace

          • strip/lstrip/rstrip

          • isdigit

          • split / rsplit

          • Supplement:

            • startswith / endswith

              name = 'alex'

# Determine if al has started
"""
# Mode 1:
flag = name.startswith('al')
print(flag)
"""
"""
# Mode 2:
val = name[0:2]
if val == 'al':
    print('In order to al Start')
else:
    print('No')
"""

            • format

              name = "My name is{0},Age:{1}".format('Old boy',73)
print(name)

            • encode

              name = 'Li Jie' # After the interpreter reads the memory, it stores it according to unicode encoding: 8 bytes.
v1 = name.encode('utf-8')
print(v1)
v2 = name.encode('gbk')
print(v2)

            • join

              name = 'alex' # a_l_e_x
result = "**".join(name) # Loop each element and add a connector between the elements.
print(result)

        • Public function

          • Index, get a character.

          • Slice to get a string (subsequence).

          • step

            name = 'alex'

# val = name[0:-1:2]
# val = name[1:-1:2]
# val = name[1::2]
# val = name[::2]
# val = name[-1:0:-2]
# print(val)
# Written questions: Please invert the string.
val = name[::-1]
print(val)

          • Length, get character length.

          • for loop

            name = 'alex'
for item in name:
    print(item)
    

            name = 'alex'
for item in name:
    print(item)
    break
    print('123')

            name = 'alex'
for item in name:
    print(item)
    continue
    print('123')

            # Exercises

# 1. for loop printing each element of "alex": for > while

# 2. Please print: 1 - 10
"""
 for i in range(1,11): # [1,2,3,4,5,6,7,8,9,10,11,12,14]  "12345678910"
     print(i)
"""

# 3. Please print: 12 3 4 5 8 9 10
"""
for i in range(1,11):
    if i == 7:
        pass
    else:
        print(i)
"""

            Note: For and while application scenarios: There is an infinite priority for, while infinite exhaustion

    5. variable

    6. Notes

    7. Conditional statement

    8. Loop statement: while + for + break + continue

    9. operator

    10. String formatting

      • %s
      • %d
      • %%

    11. Other

      • markdown Notes

      • git

        • Local: git software [Common commands]

          • git status
          • git add .
          • Git commit-m''submit records'
          • git push origin master

        • Remote: Code Cloud / github (Programmer Friendship Platform)

        • Interview related:

          1. Write out the git commands you use frequently.

          2. How did your company develop with git?

            1. Create your own warehouse on code-hosted websites such as Code Cloud or GitHub. After you create it, Code Cloud will give me a warehouse address, such as: https://gitee.com/old_boy_python_stack_21/190326032.git

            2. Write your own code.

            3. Submit the code to the remote warehouse.

              • Initialization

                • Enter an arbitrary folder, such as: D: homework\

                • git init

                • git config mailbox

                • Name of git config

                • git remote add origin https://gitee.com/old_boy_python_stack_21/190326032.git

                  Note: Git has managed the D: homework directory at this point. Any changes in this folder will be detected by git (you can see the status using the GIT status command).

              • Code collection and submission

                • git status
                • git add .
                • Git commit-m''record“
                • The git push origin master synchronizes content in the local D: homework directory to the code cloud warehouse.

              • Modify the code or delete files, etc. to operate on any files under the local D: homework.

                • git status
                • git add .
                • Git commit-m''record“
                • The git push origin master synchronizes content in the local D: homework directory to the code cloud warehouse.

              • [Avoid] If there is remote code that is not available locally, it must be executed first: [May cause merge problems]

                • git pull origin master
                • git status
                • git add .
                • Git commit-m''record“
                • The git push origin master synchronizes content in the local D: homework directory to the code cloud warehouse.

    12. summary

      1. Syntax: Variable / if/while / Operator (Auxiliary)
        1. Necessary: Variables / if/while/
        2. Focus: Strings in data types
          1. Unique function
          2. Public function
          3. for
      2. To solve practical problems:
        • Logic + Code

Detailed content

1. List

If you want to express two classmates users = Li Shao, Li Qihang... .

To represent multiple "things" later, you can use lists.

users = ["Li Shaoqi","Strange sailing",99]

  • Public function

    • len

      users = ["Li Shaoqi","Strange sailing",99]
val = len(users)
print(val) # 3

    • Indexes

      users = ["Li Shaoqi","Strange sailing",99]
val = users[0]
print(val)

    • Section

      users = ["Li Shaoqi","Strange sailing",99]

val = users[0:2]

    • Delete (except numbers/Booleans/strings)

      users = ["Li Shaoqi","Strange sailing",99]
# Mode I
users.pop(1)
print(users)

# Mode 2:
del users[1]
print(users)

      Be careful:

      • String itself cannot be modified or deleted [immutable type] v1 = alex. upper()
      • Lists are variable types.

    • Modification (except string/number/Boolean)

      users = ["Li Shaoqi","Strange sailing",99]
users[2] = 66

users[0] = 'Li Jie'
users[0][1]

    • step

      users = ["Li Shaoqi","Strange sailing",99]

val = users[0:2:2]

    • Exercises

      """
//Implement an integer addition calculator (adding two numbers):

//For example: content = input("Please enter content:") User input: 5 + 9 or 5 + 9 or 5 + 9 (including blanks), and then partition conversion to the final integer calculation results.
"""



# Idea 1:
"""
content = input('Please enter:') # [5 + 9] or [5 + 9] or [5 + 9]
content = content.strip() # [5+9] or [5+9] or [5+9]
v1 = int(content[0])
v2 = int(content[-1])
v3 = v1 + v2 
"""

# Idea 2:
"""
content = input('Please enter:') # [5 + 9] or [5 + 9] or [5 + 9]
content_len = len(content)
index = 0
total = 0
while True:
    char = content[index]
    if char.isdigit():
        total += int(char)
    index += 1
    if index == content_len:
        break
print(total)
"""

# Idea 3:
"""
content = input('Please enter:') # [5 + 9] or [5 + 9] or [5 + 9]
result = content.split('+')
# print(result) # ['55 ', ' 99 ']
v1 = int(result[0]) # "55"
v2 = int(result[1]) # " 99 "
v3 = v1 + v2
print(v3)
"""

    • for loop

      """
users = ['Li Shaoqi','Leech Airlines','Zhang Sanfeng','Li Zisen']
for i in users:
    print(i)
"""
"""
users = ['Li Shaoqi','Leech Airlines','Zhang Sanfeng','Li Zisen']
for i in users:
    # First cycle: i= "Li Shaoqi"
    print(i)
    for ele in i:
        print(ele)
"""

# Exercise Question: Please implement through for loop and digital counter: users = ['Li Shaoqi','Li Qihang','Zhang Sanfeng','Li Zisen']
"""
    0 Li Shaoqi
    1 Leech Airlines
    2 Zhang Sanfeng
    3 Li Zisen
"""
"""
# Mode I
users = ['Li Shaoqi','Leech Airlines','Zhang Sanfeng','Li Zisen']
count = 0
for i in users:
    print(count,i)
    count += 1
"""
"""
# Mode 2
users = ['Li Shaoqi','Leech Airlines','Zhang Sanfeng','Li Zisen']
users_len = len(users) # 4
for index in range(0,users_len): # [0,1,2,3]
    print(index,users[index])
"""

  • Unique function

    • Appnd, append an element to the end of the list

      users = []
users.append('alex')
print(users)

      """
//Example 1:
users = []
while True:
    name = input('Please enter your name.:')
    users.append(name)
    print(users)
"""
"""
//Example 2:
# Enter user and password
users = []
for i in range(0,3):
    name = input('Please enter a username and password:')
    users.append(name)
print(users) # ['alex,123', 'oldboy,888', 'lishaoqi,123']

# User and password verification
username = input('Please enter the username to log in:')
password = input('Please enter your login password:')
for item in users:
    result = item.split(',') # ['alex','123']
    user = result[0]
    pwd = result[1]
    if user == username and pwd == password:
        print('Successful landing')
        break
        
"""

    • insert

    • remove

    • pop

    • clear

  • Summary:

    • Add:

      • append / insert

    • Delete:

      • remove / pop / clear / del users[2]

    • Change:

      • users[3]= "new value"

    • Check:

      • Index/Slice

    • List nesting

      users = ["alex",0,True,[11,22,33,"Old boy"],[1,['alex','oldboy'],2,3]]

users[0]
users[2]
users[0][2]
users[3] # [11,22,33,'Old Boy']
users[3][-1] # "Old Boy"
users[3][-1][1] # 'male'
users[3] = 666

2. Tuples

  1. Tuple Writing Specification

    users = [11,22,33,"Old boy"] # List (Variable)

users = (11,22,33,"Old boy") # Tuples (immutable)

  2. Public function

    1. Index (excluding: int/bool)

      users = (11,22,33,"Old boy")

print(users[0])
print(users[-1])

    2. Section (exclusion: int/bool)

      users = (11,22,33,"Old boy")
print(users[0:2])

    3. Step size (excluding: int/bool)

      users = (11,22,33,"Old boy")
print(users[0:2:2])

    4. Delete (exclude: tuple/str/int/bool)

    5. Modification (exclusion: tuple/str/int/bool)

    6. for loop (excluding: int/bool)

      users = (11,22,33,"Old boy")
for item in users:
    print(item)

    7. len (exclusion: int/bool)

      users = (11,22,33,"Old boy")
print(len(users))

  3. Unique function (no)

  4. Special: Elements (sons) in tuples cannot be modified/deleted.

    # Example 1:
v1 = (11,22,33)
v1[1] = 999 # error
v1 = 999  # Correct

# Example 2: You can nest
v1 = (11,22,33,(44,55,66),(11,2,(99,88,),3))

# Example 3: Nesting
v2 = [11,22,33,(11,22,33)]
v2[-1][1] = 99 # error
v2[-1] = 123 # Correct

# Example 4: Nesting
v3 = (11,[1,2,3],22,33)
v3[1] = 666 # error
v3[1][2] = 123

summary

  1. What are the differences between interpretative and translational languages and how do you list the languages you know?

  2. String Supplementary Function

    • alone possess
      • startswith/endswith
      • format
      • encode
      • join
    • public
      • Section
      • Indexes
      • len
      • Step size (interview questions)
      • for loop
      • range(0,10) # helps you generate a list of numbers [0, 1, 2, 3, 4, 5, 6, 7, 8, 9]
    • Characteristic:
      • It is immutable, so string elements cannot be deleted or modified.

  3. git is synchronized locally and remotely, and can only be manipulated locally and submitted later.

  4. List (Variable)

    • public
      • Indexes
      • Section
      • step
      • modify
      • Delete del
      • for
      • len
    • alone possess
      • append
      • insert
      • pop
      • remove
      • clear
    • List nesting

  5. Tuples (immutable)

    • public

      • Indexes
      • Section
      • step
      • for
      • len

    • Unique function (no)

    • Tuple nesting

      v3 = (11,[1,2,3],22,33)
v3[1] = 666 # error
v3[1][2] = 123

Posted by Navajo on Sun, 28 Jul 2019 03:16:52 -0700

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