[Python] 문법 (~List)

파이썬 문법 복습하며 잊을만 하거나 잊었던 것들 기록하기

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global 선언

def myfunc():
  global x
  x = "fantastic"

myfunc()

print("Python is " + x)

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Python Data Types

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Float can also be scientific numbers with an "e" to indicate the power of 10.

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a = """Lorem ipsum dolor sit amet,
consectetur adipiscing elit,
sed do eiusmod tempor incididunt
ut labore et dolore magna aliqua."""
print(a)

결과 : Lorem ipsum dolor sit amet,
consectetur adipiscing elit,
sed do eiusmod tempor incididunt
ut labore et dolore magna aliqua.

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for문 돌릴 때 range 주의하기

a = "banana"

for x in a:
  print(x) 

for x in range(len(a)):
  print("d")

결과 :
b
a
n
a
n
a
d
d
d
d
d
d

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Remove Whitespace

a = " Hello, World! "
print(a.strip())

결과 : "Hello, World!"

Replace String

print(a.replace("H", "J"))

Split String

print(a.split(","))

결과 : ['Hello', ' World!']

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String Format

age = 36
txt = "My name is John, and I am {}"
print(txt.format(age))

중괄호 주의하자!

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Escape Characters

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Insert Items

thislist = ["apple", "banana", "cherry"]
thislist.insert(2, "watermelon")
print(thislist)

결과 : ['apple', 'banana', 'watermelon', 'cherry']

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Extend List

thislist = ["apple", "banana", "cherry"]
tropical = ["mango", "pineapple", "papaya"]
thislist.extend(tropical)
print(thislist)

결과 : ["apple", "banana", "cherry","mango", "pineapple", "papaya"]

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Remove Specified Index

thislist = ["apple", "banana", "cherry"]
thislist.pop(1)
print(thislist)

결과 : ["apple","cherry"]

그냥 pop()은 last in first out

del thislist[0]

thislist.clear()

→ 다 지우기

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For문 돌릴 때 주의!!

thislist = ["apple", "banana", "cherry"]

for x in thislist:
  print(x)

for i in range(len(thislist)):
  print(thislist[i])

결과 :
apple
banana
cherry
apple
banana
cherry

Len 주의할 것!!

thislist = ["apple", "banana", "cherry"]
[print(x) for x in thislist]

→ 이런 방법도 있음

newlist = [x for x in range(10) if x < 5]

→ 이런 Syntax도 있음

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Sort List

thislist.sort()
thislist.sort(reverse = True)
thislist.sort(key = str.lower)
thislist.reverse()

def myfunc(n):
  return abs(n - 50)

thislist = [100, 50, 65, 82, 23]
thislist.sort(key = myfunc)
print(thislist)

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Copy a List

thislist = ["apple", "banana", "cherry"]
mylist = thislist.copy()
print(mylist)

thislist = ["apple", "banana", "cherry"]
mylist = list(thislist)
print(mylist)

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List Methods

참고 : W3schools