Python basics

Basic knowledge of Python. This is my study memo. Please do not excessive expectations.

Basic knowledge

-The extension of the Python program file is py 例：××××.py

When using IDLE

・ Shell window IDLE started

・ Editor window -The one that inputs the program is called a text editor -Create new file-> " File "->" New File " in the menu bar of IDLE's shell window -Save-> When writing a program in the editor window and saving the file, " File "->" Save as ... " in the menu bar of the editor window. -Open File-> " File "->" Open " in the menu bar of the editor window -Run program-> "Run"-> "Run Module F5" in the menu bar of the editor window `

order

-Output print () Use the command print () to output a character string regardless of whether it is full-width or half-width. Also, to handle character strings, use double quotation ("") andsingle quotation ('')to wrap around. Example: print ("Good morning") → Good morning

・ Input ʻinput () If you use it likevariable = input ('the string you want to display on the console')`, the value entered in the console will be assigned to the variable. Also, since the value received by input becomes a character string type, it is necessary to convert it to a numeric type (use "int").

variable

・ How to name variables -1, Use English words, the first letter of the variable name cannot be a number Example: date -2, When using variable names of two or more words, separate words with _ (underscore) Example: user_name

-Retrieve the value of a variable

name = "Jhon"
print(name)  # →　Jhon
print("name")  # → name　#If you add double quotation marks, it will be recognized as a character string.

-Update the value of the variable

Type conversion

-Use " str " to convert a numeric type to a string type

Example

price = 200  #Numeric type
print("The price of apples"+ str(price) + "It's a yen")

-Use " int " to convert string type to numeric type

Example

count = "3"
price = 100
total_price = price * int(count)

if statement

How to write

××××.py

score = 50
if score ==100: #Colon required at end of line
    print("Equal numbers")
#Align the indents (4 half-width spaces)

××××.py

score = 50
if score ==100: #Colon required at end of line
    print("Equal numbers")
#Align the indents (4 half-width spaces)
else: #Colon required at end of line
    print("Different numbers")
#Align the indents (4 half-width spaces)

××××.py

score = 80
if score ==100: #Colon required at end of line
    print("Equal numbers")
#Align the indents (4 half-width spaces)
elif score >=70: #Colon required at end of line
    print("Greater than 70")
else: #Colon required at end of line
    print("Different numbers")
#Align the indents (4 half-width spaces)

××××.py

# and -"When both condition 1 and condition 2 are satisfied"
x = 20
if x>=10 and x<=30:
    print("x is 10 or more and 30 or less")

# or -"When condition 1 or condition 2 is satisfied"
y = 60
if y<10 or y>30:
    print("y is less than 10 or greater than 30")

# not -"If the conditional expression is False, it will be True"
z = 55
if not z== 77:
    print("z is not 77")