001-2. Introduction to Python
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# Day_01_01_Basic.py
# You can run code in PyCharm by "run"(alt shift f10) and select file which you want to run
# After once run, you can immediately run code by shift f10
print('Hello, python!')
print('Hello, python!'*3)
print('Hello, python!Hello, python!Hello, python!')
print('Hello, python!')
print('Hello, python!')
print('Hello, python!')
print("Hello, python!" "Hello, python!" "Hello, python!")
# You can connect upper line and lower line by back slash
# This make you arrange data as screen shows
print("Hello, python!" \
"Hello, python!" \
"Hello, python!")
# You can remove back slashes
# but you never run into any issues with back slashes when you have new line
print("Hello, python!"
"Hello, python!"
"Hello, python!")
# It's standard to separate data and data by commma
# Since print() is defined with variadic Parameters,
# so, I can pass arguments into print() as much as what I want to pass
print("Hello, python!", "Hello, python!", "Hello, python!")
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# You can copy and paste one line by "ctrl c, ctrl v"
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# In some other languages, single quatation and double quatation has difference
# 'A', "ABC"
# However, in Python, single quatation and double quatation has no difference
# 문제
# Hello, python!을 3회 출력하는 코드를 3가지 만들어 보세요.
# Programming : The process of making "program"
# Program : It's composed of "code" and "data"
# Data : It can be divided into "variable which changes" and "constant which doesn't change"
# We don't care much about constant because it doesn't change
# Data type :
# "Numeric"(float(real number),
# "integer"(-1,0,1)),
# Character(string(sequence of characters)),
# "boolean"(true, false)
# In Python, 'one character' and "sequence of characters" don't have difference
# Imaginary number makes calculation easy in mathematics
# but we generally don't treat imaginary number in programming
# Imaginary number can be processed by external module rather than Python itself
print(3.14, 56, 'hello', True)
# This code shows data type
print(type(3.14), type(56), type('hello'), type(True))
# # I use assignment operator(=)
# "a" is variable
a = 3.14
print(3.14, a)
a = 56
print(a, type(a))
# \n is newline character
print('hell\no, python!')
print('"hello"')
# output:"hello"
print("'hello'")
# output:'hello'
# For section line
print('-'*50)
# Other language specifies data type in front of name of variable like "int a = 7"
# But Python doesn't do that so we say Python doesn't have data type
# But Python uses data type internally
# Comment is ctrl / or ctrl k,c
# a = 7
# b = 19
# The following syntax is Python friendly syntax
a, b = 7, 19
# The following syntax is not possible in Python
# a = 7, b = 19
# If you want to use above similar syntax, you can you semi colon between variable
# You can write multiple parts in one line by using semi colon
# But Python doesn't use semicolon much, so don't recommend this syntax
# a = 7; b = 19
print(a, b)
# 문제
# 아래쪽 코드에서 거꾸로 출력하도록 코드를 추가해 보세요.
# a와 b를 서로 교환합니다.
# bug.
# a = 19
# b = 7
# Let's see answer
# Suppose there are "juice" and "coke"
# And I want to swap position of juice and coke
# I first need empty cup
# I put juice in empty cup
# 빈컵 = 주스
# I put coke in juice's cup
# 주스 = 콜라
# I put juice in empty cup in coke's cup
# 콜라 = 빈컵
# Let's swap
t = a
a = b
b = t
print(a, b)
# But in Python, we don't above way for swap
# If you want to swap "a" and "b", you can use "transposition for muliple elements"
# I put b in a, I put a in a
a, b = b, a
print(a, b)
# Languages which can pass multiple values
# to multiple variable "at once" by using assignment operator are a few,
# such as Python and other recent a few languages
# Actually, "a, b = b, a" code should be translated into "swap" code internally
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