▶ Python Overview

• 파이썬은 interpreted language(한줄씩)
• C와 같은 compiler language(한번에 돌아가는 언어)
• Object-Oriented
• dynamically typed language

▶ Constructor(생성자)

`

w = Widget()
w = Widget(a,b,c)

▶ Calling Methods

▶ Built-In Classes

• Immutable class
  : fixed value upon instantiation that can not subsequently be changed
  e.x) float class is immutable

▶ class

Bool class

int class

# 캐스팅
int(3.14)
# -> answer: 3

float class

float(2)
# floating point value 2.0
# -> answer: 2.0

list class

• list('hello') -> list of characters ['h', 'e', 'l', 'l', 'o']

tuple class

• immutable version of sequence

The str class

print("""Welcome to GPA calculator. Please Enter the push button!""")

The set class

The dict class

▶ Operators

Logical Operators

• short-circuit

Equality Operators

Comparison Operators

Arithmetic Operator

Bitwise Operator

• Python provides the following bitwise operators for integers

Sequence Operator

Sequence Comparisons

Operators for Sets

Operators for Dictionaries

▶ Conditionals

▶ Loops

While Loops

For Loops

Indexed For loop

Break and Continue Statements

▶ Functions

def count(data, targe):
	n = 0
    for item in data:
    	if item == target:
        n += 1
    return n

Information Passing

▶ Simple I/O

files

▶ Exception Handling

Common Exceptions

Raising an Exception

raise ValueError('x cannot be nemgative')

Catching an Exception

• 예외 처리를 함으로써 성능 향상을 꾀할 수 있음.
• try-catch문을 이용하여 예외 처리 가능

try:
	ratio = x/y
except ZeroDivisionError:
    ...do something else...

▶ Iterators and Generators

Iterators

• each call to the built-in function, next(i), produces a subsequent element from the underlying series, with a StopIteration exception raised to indicate that there are no further elements.
• An iterable is an object, obj, that produces an iterator via the syntax iter(obj)

Generators

• generator for the factors of n

def factors(n):
	for k in range(1, n+1):
    	if n % k == 0:
        	yield k

▶ Additional Python Conveniences

Conditional Expressions

Comprehension Syntax

[expression for value in iterable if condition]

is same as

result = []
for value in iterable:
	if condition:
    	result.append(expression)

Packing and Unpacking

Packing

data = 2, 4, 6, 8

• data being assigned to the tuple (2,4,6,8)
• automatic packing of tuple

Unpacking

a,b,c,d = range(7, 11)

• assigning
  a = 7, b = 8, c = 9, d = 10

▶ Modules

import math