Python Tutorial -1-
Toku
April 1, 2023
Python & VSCode
https://www.youtube.com/watch?v=6i3e-j3wSf0&t=309s
https://github.com/gitdagray/python-course
Dev/python/python-basic/lesson01
Control+Shift+P=>Python:Select Interpreter
user@mbp python-basic % python3 --version
Python 3.10.3
windows は py -3 --version
REPEL = Read-Evaluate-Print-Loop
user@mbp python-basic % python
Python 3.10.3 (main, Apr 23 2022, 13:42:19) [Clang 13.1.6 (clang-1316.0.21.2)] on darwin
Type "help", "copyright", "credits" or "license" for more information.
>>> 2+2
4
>>> name='Dave'
>>> name
'Dave'
>>> quit()
user@mbp python-basic %
Control + N で新しいファイルが出てくる
greeting = 'Hello World'
print(greeting)
user@mbp Lesson01 % python3 Hello.py
Hello World
ファイルを右クリック=＞ターミナルで python ファイルを実行する
user@mbp python-basic % python3
Python 3.10.3 (main, Apr 23 2022, 13:42:19) [Clang 13.1.6 (clang-1316.0.21.2)] on darwin
Type "help", "copyright", "credits" or "license" for more information.
>>> name='Dave'
>>> name
'Dave'
>>> name001 = 'Dave'
>>> name001
'Dave'
>>> _name='Dave'
>>> _name
'Dave'
>>> name!='Dave'
False
>>> name-first='Dave'
File "<stdin>", line 1
name-first='Dave'
^^^^^^^^^^
SyntaxError: cannot assign to expression here. Maybe you meant '==' instead of '='?
>>> 1name='Dave'
File "<stdin>", line 1
1name='Dave'
^
SyntaxError: invalid decimal literal
>>> if = 'Dave' # 予約語
File "<stdin>", line 1
if = 'Dave'
^
SyntaxError: invalid syntax
>>> for = 'Dave'
File "<stdin>", line 1
for = 'Dave'
^
SyntaxError: invalid syntax
SyntaxError: invalid syntax
>>> 2 + 2 # Expression
4
>>> "Expression" # Expression
'Expression'
>>> myname = 'Dave' # Statement
>>> myname
'Dave'
>>> quit()
# Lesson02/welcome.py
line01 = "********************"
line02 = "* *"
line03 = "* WELCOME! *"
print('')
print(line01)
print(line02)
print(line03)
print(line02)
print(line01)
user@mbp Lesson02 % python welcome.py
Control + , => 設定画面 => format on save => Editor ›
Format On Save
Editor: Format On Save Mode =>file
python > formatting: => Python › Formatting: Provider
autopep8
Lesson3 Operators
https://www.youtube.com/watch?v=7BxUaeROVXI
user@mbp Lesson03 % python3
Python 3.10.3 (main, Apr 23 2022, 13:42:19) [Clang 13.1.6 (clang-1316.0.21.2)] on darwin
Type "help", "copyright", "credits" or "license" for more information.
>>> 2 + 2
4
>>> 4 -2
2
>>> 2 * 2
4
>>> 24 / 5
4.8
>>> 24 // 5
4
>>> round(24 / 5)
5
>>> 24 % 5
4
>>> 2 ** 3
8
>>> 2 ** 5
32
>>> meaning = 42
>>> meaning += 1
>>> meaning
43
>>> meaning -= 1
>>> meaning
42
>>> meaning /= 10
>>> meaning
4.2
>>> "Dave " + "Gray"
'Dave Gray'
>>> quit()
右にある「・・・」ボタンをクリックするとクリアできる
>>> 42 == 41
False
>>> 42 == 42
True
>>> 42 != 41
True
>>> 10 > 5
True
>>> 10 >= 5
True
>>> 10 <= 10
True
>>> x = True
>>> y = False
>>> z = True
>>> not x
False
>>> not y
True
>>> x and y
False
>>> y and x
False
>>> x or y
True
>>> y or x
True
>>> x and z
True
>>> z and y
False
>>> y or z
True
>>> z or y
True
>>>
meaning = 8
print('')
if meaning > 10:
print('Right on!')
else:
print('Not today')
user@mbp python-basic % cd Lesson03
user@mbp Lesson03 % python3 meaning.py
Not today
# Ternary Operator
print('Right on!') if meaning > 10 else print('Not today')
【VSCode】Python を 1 行毎に変数の中身見ながらステップ実行する方法 => F10
Lesson4 Data Types
first = "Dave"
last = "Gray"
print(type(first)) # <class 'str'>
実行するときは▷ボタンの右の下矢印をクリックして新しいPythonファイル
first = "Dave"
last = "Gray"
print(type(first))
print(type(first) == str) # True
print(isinstance(first, str)) # # True
constructor function
# constructor function
pizza = str("Pepperoni")
print(type(pizza)) # <class 'str'>
print(type(pizza) == str) # True
print(isinstance(pizza, str)) # True
Concatenation
# Concatenation
fullname = first + " " + last
print(fullname) # Dave Gray
fullname += "!"
print(fullname) Dave Gray!
Casting a number to a string
# Casting a number to a string
decade = str(1980)
print(type(decade)) # <class 'str'>
print(decade) # 1980
statement = "I like rock music from the " + decade + "s."
print(statement) # I like rock music from the 1980s.
Multiple lines
multiline = '''
Hey, how are you?
I was just checking in.
All good?
'''
print(multiline)
Hey, how are you?
I was just checking in.
All good?
Escaping special characters
# Escaping special characters
sentence = 'I\'m back at work!\tHey!\n\nWhere\'s this at\\located?'
print(sentence)
I'm back at work! Hey!
Where's this at\located?
String Methods
print(first) # Dave
print(first.lower()) # dave
print(first.upper()) # DAVE
print(first) # Dave
print(multiline.title())
Hey, How Are You?
I Was Just Checking In.
All Good?
print(multiline.replace("good", "ok"))
Hey, how are you?
I was just checking in.
All ok?
print(multiline)
Hey, how are you?
I was just checking in.
All good?
print(len(multiline)) # 124
multiline += " "
multiline = " " + multiline
print(len(multiline)) # 182
# 両側のスペースを切りとる
print(len(multiline.strip())) # 122
# 左側のスペースを切りとる
print(len(multiline.lstrip())) # 163
# 右側のスペースを切りとる
print(len(multiline.rstrip())) # 141
print("")
Build a menu
# Build a menu
title = "menu".upper()
print(title.center(20, "="))
print("Coffee".ljust(16, ".") + "$1".rjust(4))
print("Muffin".ljust(16, ".") + "$2".rjust(4))
print("Cheesecake".ljust(16, ".") + "$4".rjust(4))
print("")
========MENU========
Coffee.......... $1
Muffin.......... $2
Cheesecake...... $4
string index values
# string index values
first = "Dave"
print(first[1]) # a
print(first[-1]) # e
print(first[1:-1]) # av
print(first[1:]) # ave
Some methods return boolean data
# Some methods return boolean data
print(first.startswith("D")) # True
print(first.endswith("Z")) # False
Boolean data type
# Some methods return boolean data
myvalue = True
x = bool(False)
print(type(x)) # <class 'bool'>
print(isinstance(myvalue, bool)) # True
Numeric data types
# integer type
price = 100
best_price = int(80)
print(type(price)) # <class 'int'>
print(isinstance(best_price, int)) # True
# float type
gpa = 3.28
y = float(1.14)
print(type(gpa)) <class 'float'>
# complex type
comp_value = 5+3j
print(type(comp_value)) # <class 'complex'>
print(comp_value.real) # 5.0
print(comp_value.imag) # 3.0
# Built-in functions for numbers
print(abs(gpa)) # 3.28
print(abs(gpa * -1)) # 3.28
print(round(gpa)) # 3
print(round(gpa, 1)) # 3.3
import math
print(math.pi) # 3.141592653589793
print(math.sqrt(64)) # 8.0
print(math.ceil(gpa)) # 4 切り上げ
print(math.floor(gpa)) # 3 切り捨て
Casting a string to a number
# Casting a string to a number
zipcode = "10001"
zip_value = int(zipcode)
print(type(zip_value)) <class 'int'>
Error if you attempt to cast incorrect data
# Error if you attempt to cast incorrect data
zip_value = int("New York") # ValueError
Lesson5 User Input
Macのパソコンで[optionキー]を押しながら[￥マークのキー]を押すとバックスラッシュが入力: Alt + ¥
長いテキストのテキストの折り返し=>［Alt］＋［Z］キーを押す（macOSでは［Option］＋［Z］キー）: Ctrl+Z
実行するときは▷ボタンの右の下矢印をクリックして新しいPythonファイル
Mac絵文字はControl＋Command＋スペースバーを押す： Ctrl + Win + Space
value = input('Please enter a value\n')
print(value)
ランダムに要素を一つ選択: random.choice()
import random
l = [0, 1, 2, 3, 4]
print(random.choice(l))
# 1
タプルや文字列でも同様。文字列の場合は一文字が選択される。
print(random.choice(('xxx', 'yyy', 'zzz')))
# yyy
print(random.choice('abcde'))
# b
from enum import Enum
class RPS(Enum):
ROCK = 1
PAPER = 2
SCISSORS = 3
print(RPS(2)) # RPS.PAPER
print(RPS.ROCK) # RPS.ROCK
print(RPS['ROCK']) # RPS.ROCK
print(RPS.ROCK.value) # 1
import os, sys
print('環境変数')
for k, v in os.environ.items():
print(f'{k}={v}')
print('引数')
for i in range(len(sys.argv)):
print(f'{i}={sys.argv[i]}')
import sys
import random
from enum import Enum
class RPS(Enum):
ROCK = 1
PAPER = 2
SCISSORS = 3
print("")
playerchoice = input(
"Enter...\n1 for Rock,\n2 for Paper, or \n3 for Scissors:\n\n")
if not playerchoice.strip().isnumeric():
sys.exit("You must enter number")
player = int(playerchoice)
if player < 1 | player > 3:
sys.exit("You must enter 1, 2, or 3.")
computerchoice = random.choice("123")
computer = int(computerchoice)
print("")
print("You chose " + str(RPS(player)).replace('RPS.', '') + ".")
print("Python chose " + str(RPS(computer)).replace('RPS.', '') + ".")
print("")
if player == 1 and computer == 3:
print("🎉 You win!")
elif player == 2 and computer == 1:
print("🎉 You win!")
elif player == 3 and computer == 2:
print("🎉 You win!")
elif player == computer:
print("😲 Tie game!")
else:
print("🐍 Python wins!")
Lesson6 List & Tuples
https://www.youtube.com/@DaveGrayTeachesCode/videos
https://www.youtube.com/watch?v=KWKWswDfAb0
ターミナルを右に寄せる: 表示=>外観=>パネルの位置=>右
users = ['Dave', 'John', 'Sara']
data = ['Dave', 42, True]
emptylist = []
print("Dave" in emptylist) # False
print(users[0]) # Dave
print(users[-2]) # John
print(users.index('Sara')) # 2
print(users[0:2]) # ['Dave', 'John']
print(users[1:]) # ['John', 'Sara']
print(users[-3:-1]) # ['Dave', 'John']
print(len(data)) # 3
users.append('Elsa') # リストの最後に追加
print(users) # ['Dave', 'John', 'Sara', 'Elsa']
# users += 'Jason' # ['Bob', 'Dave', 'John', 'Sara', 'Elsa', 'J', 'a', 's', 'o', 'n']
users += ['Jason'] # リストの結合
print(users) # ['Dave', 'John', 'Sara', 'Elsa', 'Jason']
users.extend(['Robert', 'Jimmy']) # リストを追加する
print(users) # ['Dave', 'John', 'Sara', 'Elsa', 'Jason', 'Robert', 'Jimmy']
# users.extend(data)
# print(users) # ['Dave', 'John', 'Sara', 'Elsa', 'Jason', 'Robert', 'Jimmy', 'Dave', 42, True]
users.insert(0, 'Bob') # 挿入
print(users) # ['Bob', 'Dave', 'John', 'Sara', 'Elsa', 'Jason', 'Robert', 'Jimmy']
users[2:2] = ['Eddie', 'Alex'] # 複数挿入
print(users) # ['Bob', 'Dave', 'Eddie', 'Alex', 'John', 'Sara', 'Elsa', 'Jason', 'Robert', 'Jimmy']
users[1:3] = ['Robert', 'JPJ'] # Replace
print(users) # ['Bob', 'Robert', 'JPJ', 'Alex', 'John', 'Sara', 'Elsa', 'Jason', 'Robert', 'Jimmy']
users.remove('Bob')
print(users) # ['Robert', 'JPJ', 'Alex', 'John', 'Sara', 'Elsa', 'Jason', 'Robert', 'Jimmy']
print(users.pop()) # Jimmy 最後の要素取り出す
print(users) # ['Robert', 'JPJ', 'Alex', 'John', 'Sara', 'Elsa', 'Jason', 'Robert']
del users[0] # 削除
print(users) # ['JPJ', 'Alex', 'John', 'Sara', 'Elsa', 'Jason', 'Robert']
# del data ＃ 変数全体要素を削除
data.clear()
print(data) # []
users[1:2] = ['dave'] # 最初が小文字のものを挿入
users.sort()
print(users) # ['Elsa', 'JPJ', 'Jason', 'John', 'Robert', 'Sara', 'dave'] ＃ 小文字は大文字の後にくる
users.sort(key=str.lower)
print(users) # ['dave', 'Elsa', 'Jason', 'John', 'JPJ', 'Robert', 'Sara']
nums = [4, 42, 78, 1, 5]
nums.reverse() # 逆順にする
print(nums) # [5, 1, 78, 42, 4]
# nums.sort(reverse=True) ＃ ソートしたものを逆順にする
# print(nums) ＃ [78, 42, 5, 4, 1] numsが変わる
print(sorted(nums, reverse=True)) # [78, 42, 5, 4, 1] Global Sorted Function
print(nums) # [5, 1, 78, 42, 4] # numsは変わらない
# コピー
numscopy = nums.copy()
mynums = list(nums) # constructor
mycopy = nums[:] # slice all list
print(numscopy) # [5, 1, 78, 42, 4]
print(mynums) # [5, 1, 78, 42, 4]
mycopy.sort()
print(mycopy) # [1, 4, 5, 42, 78]
print(nums) # [5, 1, 78, 42, 4]
print(type(nums)) # <class 'list'>
mylist = list([1, "Neil", True]) # コンストラクタでリストを作成する
print(mylist) # [1, 'Neil', True]
# Tuples
mytuple = tuple(('Dave', 42, True)) # コンストラクタでタプルを作成する
print(mytuple) # ('Dave', 42, True)
print(type(mytuple)) # <class 'tuple'>
# タプルは追加や変更ができない
newlist = list(mytuple) # タプルをリストに変換
newlist.append('Neil')
newtuple = tuple(newlist) # リストをタプルに変換
print(newtuple) # ('Dave', 42, True, 'Neil')
anothertuple = (1, 4, 2, 8, 2, 2)
print(type(anothertuple)) # <class 'tuple'>
(one, *two, hey) = anothertuple
print(one) #️ 1
print(two) #️ [4, 2, 8, 2] リスト
print(hey) #️ ２
print(anothertuple.count(2)) #️ ２が３個ある
Lesson7 Dictionaries & Sets
# Dictionaries
band = {
"vocals": "Plant",
"guitar": "Page"
}
# constructor function
band2 = dict(vocals="Plant", guitar="Page")
print(band) # {'vocals': 'Plant', 'guitar': 'Page'}
print(band2) # {'vocals': 'Plant', 'guitar': 'Page'}
print(type(band)) # <class 'dict'>
print(len(band)) # 2
# Access items
print(band["vocals"]) # Plant
print(band.get("guitar")) # Page
# list all keys
print(band.keys()) # dict_keys(['vocals', 'guitar'])
# list all values
print(band.values()) # dict_values(['Plant', 'Page'])
# list of key/value pairs as tuples
print(band.items()) # dict_items([('vocals', 'Plant'), ('guitar', 'Page')])
True
# verify a key exists
print("guitar" in band)
print("triangle" in band)
# Change values
band["vocals"] = "Coverdale"
band.update({"bass": "JPJ"})
print(band)
# Remove items
print(band.pop("bass"))
print(band)
band["drums"] = "Bonham"
print(band)
print(band.popitem()) # tuple
print(band)
# Delete and clear
band["drums"] = "Bonham"
del band["drums"]
print(band)
band2.clear()
print(band2)
del band2
# Copy dictionaries
# band2 = band # create a reference
# print("Bad copy!")
# print(band2)
# print(band)
# band2["drums"] = "Dave"
# print(band)
band2 = band.copy()
band2["drums"] = "Dave"
print("Good copy!")
print(band)
print(band2)
# or use the dict() constructor function
band3 = dict(band)
print("Good copy!")
print(band3)
# Nested dictionaries
member1 = {
"name": "Plant",
"instrument": "vocals"
}
member2 = {
"name": "Page",
"instrument": "guitar"
}
band = {
"member1": member1,
"member2": member2
}
print(band)
print(band["member1"]["name"])
# Sets
nums = {1, 2, 3, 4}
nums2 = set((1, 2, 3, 4))
print(nums)
print(nums2)
print(type(nums))
print(len(nums))
# No duplicate allowed
nums = {1, 2, 2, 3}
print(nums)
# True is a dupe of 1, False is a dupe of zero
nums = {1, True, 2, False, 3, 4, 0}
print(nums)
# check if a value is in a set
print(2 in nums)
# but you cannot refer to an element in the set with an index position or a key
# Add a new element to a set
nums.add(8)
print(nums)
# Add elements from one set to another
morenums = {5, 6, 7}
nums.update(morenums)
print(nums)
# you can use update with lists, tuples, and dictionaries, too.
# Merge two sets to create a new set
one = {1, 2, 3}
two = {5, 6, 7}
mynewset = one.union(two)
print(mynewset)
# Keep only the duplicates
one = {1, 2, 3}
two = {2, 3, 4}
one.intersection_update(two)
print(one)
# Keep everything except the duplicates
one = {1, 2, 3}
two = {2, 3, 4}
one.symmetric_difference_update(two)
print(one)