(Python : Basic) 1. 기초문법

Posted by : Python at Sep 1, 2021

Category : Python

print

print(10 + 5)
print(10 - 5)
print(10 * 5)
print(10 / 5)

import math
print(math.ceil(2.2))
print(math.floor(2.7))
print(math.pow(2,10))
print(math.pi)

print('Hello')
print("Hello")
print("Hello 'world'")
print('Hello "world"')

# 실행결과
$ Hello
$ Hello
$ Hello 'world'
$ Hello "world"

print('Hello '+'world')
print('Hello '*3)
print('Hello'[0])
print('Hello'[1])
print('Hello'[2])

# 실행결과
$ Hello world
$ Hello Hello Hello
$ H
$ e
$ l

print('hello world'.capitalize())
print('hello world'.upper())
print('hello world'.__len__())
print(len('hello world'))
print('Hello world'.replace('world', 'programming'))

# 실행결과
$ Hello world
$ HELLO WORLD
$ 11
$ 11
$ Hello programming

변수

name = "이상효"
print("안녕하세요. "+name+"님")
print(name+"님을 위한 강의를 준비했습니다.")
print(name+"님 꼭 참석 부탁드립니다.")

donation = 200
student = 10
sponsor = 100
print((donation*student)/sponsor)

if

input = 33
real_egoing = 11
real_k8805 = "ab"
if real_egoing == input:
  print("Hello!, egoing")
elif real_k8805 == input:
  print("Hello!, k8805")
else:
  print("Who are you?")

in_str = input("아이디를 입력해주세요.\n")
real_egoing = "egoing"
real_k8805 = "k8805"
if real_egoing == in_str or real_k8805 == in_str:
  print("Hello!")
else:
  print("Who are you?")

주석

'''
조건문 예제
egoing
2015
'''

"""
이거도 됨.
"""

# user input password
input = 33
real_egoing = 11
#real_k8805 = "ab"
if real_egoing == input:
  print("Hello!, egoing")
#elif real_k8805 == input:
#  print("Hello!, k8805")
else:
  print("Who are you?")

list 데이터 타입

print(type('egoing')) #<class 'str'>
name = 'egoing'
print(name) #egoing
print(type(['egoing', 'leezche', 'graphittie'])) #<class 'list'>
names = ['egoing', 'leezche', 'graphittie']
print(names) 
print(names[2]) #graphittie
egoing = ['programmer', 'seoul', 25, False]
egoing[1] = 'busan'
print(egoing) #['programmer', 'busan', 25, False]

반복문

i = 0
while i < 3:
    print('Hello world')
    i = i + 1

i = 0
while i < 10:
    print('print("Hello world '+str(i*9)+'")')
    i = i + 1

i = 0
while i < 10:
    if i == 4:
        break
    print(i)
    i = i + 1
print('after while')

input_id = input("아이디를 입력해주세요.\n")
members = ['egoing', 'k8805', 'leezche']
for member in members:
    if member == input_id:
        print('Hello!, '+member)
        import sys
        sys.exit()
print('Who are you?')

함수

def a3():
    print('aaa')
a3()

def a3():
    return 'aaa'
print(a3())

def a(num):
    return 'a'*num
print(a(3))

def make_string(str, num):
    return str*num
print(make_string('b', 3))

input_id = input("아이디를 입력해주세요.\n")

def login(_id):
    members = ['egoing', 'k8805', 'leezche']
    for member in members:
        if member == _id:
            return True
    return False

if login(input_id):
    print('Hello, '+input_id)
else:
    print('Who are you?')

모듈(외부 함수) 사용하기

python 내장 모듈

import math
print(math.ceil(2.9))
print(math.floor(2.9))
print(math.sqrt(16))

# 실행결과
3
2
4.0

모듈 작성

# egoing.py
def a():
    return 'a'
def b():
    return 'b'
def c():
    return 'c'

# k8805.py
def a():
    return 'B'

from egoing import a as z
import k8805 as k
print(z())
print(k.a())

모듈 작성2

# auth.py
def login(_id):
    members = ['egoing', 'k8805', 'leezche']
    for member in members:
        if member == _id:
            return True
    return False

import auth
input_id = input("아이디를 입력해주세요.\n")
if auth.login(input_id):
    print('Hello, '+input_id)
else:
    print('Who are you?')

클래스

class Cal(object):
    def __init__(self, v1, v2):
        self.v1 = v1
        self.v2 = v2
 
    def add(self):
        return self.v1+self.v2
 
    def subtract(self):
        return self.v1-self.v2
 
 
c1 = Cal(10,10)
print(c1.add())
print(c1.subtract())
c2 = Cal(30,20)
print(c2.add())
print(c2.subtract())

상속

class Class1(object):
    def method1(self): return 'm1'
c1 = Class1()
print(c1, c1.method1())
 
class Class3(Class1):
    def method2(self): return 'm2'
c3 = Class3()
print(c3, c3.method1())
print(c3, c3.method2())
 
class Class2(object):
    def method1(self): return 'm1'
    def method2(self): return 'm2'
c2 = Class2()
print(c2, c2.method1())
print(c2, c2.method2())

static, class 선언

class Cs:
    @staticmethod
    def static_method():
        print("Static method")
    @classmethod
    def class_method(cls):
        print("Class method")
    def instance_method(self):
        print("Instance method")
i = Cs()
Cs.static_method()
Cs.class_method()
i.instance_method()

class Cs:
    count = 0
    def __init__(self):
        Cs.count = Cs.count + 1
    @classmethod
    def getCount(cls):
        return Cs.count
i1 = Cs()
i2 = Cs()
i3 = Cs()
i4 = Cs()
print(Cs.getCount())