파이썬 3일차

- for문

test_list = [103, 'test3', [1033, 'test3-1']]
empty_list = []

for i in range(10):
        print(i)


for j in range(2):
        for k in range(3):
                empty_list.append((j,k))
print(empty_list)
        
for n in test_list:
        print(n)

-------결과값-------

0
1
2
3
4
5
6
7
8
9
[(0, 0), (0, 1), (0, 2), (1, 0), (1, 1), (1, 2)]
103
test3
[1033, 'test3-1']

이중 for문 중요!!!


- if문
참 = 1, 거짓 = 0


- 내장함수 iter
next 함수로 숫자를 하나씩 빼올 수 있음

iterator_num = iter(range(3))
print("1 :",next(iterator_num))
print("2 :",next(iterator_num))
print("3 :",next(iterator_num))
try:
        print("4.",next(iterator_num))
except Exception as ex:
        print("you over 4 times")
        print(ex)

-------결과값-------

1 : 0
2 : 1
3 : 2
you over 4 times

 

- 여러가지 내장 함수
1. enumberate (range처럼 씀, 코스프로에서 출제됨)

enumerate_list = ["hi","my","name","is","LTH"]

# 2개의 값중 첫번째 값은 인덱스(순서) 두번째 값은 값을 반환함.
for ind, val in enumerate(enumerate_list):
        print(ind, " --- ", val)

-------결과값-------

0  ---  hi
1  ---  my
2  ---  name
3  ---  is
4  ---  LTH

 

2. f'()'

format_num1 = 100
format_num2 = 200
# f'{}'는 문자안에 변수를 사용하고 싶을때 사용함.
print(f"1. this is format_number1 : {format_num1}, format_number2 : {format_num2}")
print("2. this is format_number1 : {}, format_number2 : {}".format(format_num1, format_num2))

//print(f"~~{변수}~~")

-------결과값-------

1. this is format_number1 : 100, format_number2 : 200
2. this is format_number1 : 100, format_number2 : 200

 

3. .split("")

# .split("??") ??값을 기준으로 나눈후 리스트 형태로 저장함.
split_this_strings = "Split this string using spaces by utilizing the split function."
print(split_this_strings.split(" "))

-------결과값-------

['Split', 'this', 'string', 'using', 'spaces', 'by', 'utilizing', 'the', 'split', 'function.']

 

4. "".join(), 괄호 안에 있는 값을 큰따옴포를 이용해서 붙인 후 문자열로 반환

list_to_strings = ["what","are","you","doing"]
print(" ".join(list_to_strings))
print("+".join(list_to_strings))

-------결과값-------

what are you doing
what+are+you+doing

 

5. map(,)

# map(??,!!)은 for문의 축약 형태이며 !!에 있는 각각의 값들에 ??함수를 적용함.
mapping_this_list = ["a","b","c","d","z"]
print(list(map(ord,mapping_this_list)))
[97, 98, 99, 100, 122]

 

6. filler(,)

# filter(??,!!)은 map과 비슷한 형태이지만 True, False로 포함할지를 결정 가능함.
filtering_this_list = [1, 2, 3, 4, 5, 6, 7, 8, 9, 10]

def is_even(n):
    return True if n % 2 == 0 else False

print(list(filter(is_even, filtering_this_list)))

-------결과값-------

[2, 4, 6, 8, 10]

 

7. comprehension 

# for문을 줄여 쓸수 있음.
comprehension_list = ["tail","alphabet","egg","horse","elment","error"]
result_comp_list1 = [i for i in comprehension_list]
result_comp_list2 = [i[0] for i in comprehension_list]
result_comp_list3 = [(i, j) for i in range(3) for j in range(4)]
print(result_comp_list1)
print(result_comp_list2)
print(result_comp_list3)

-------결과값-------

['tail', 'alphabet', 'egg', 'horse', 'elment', 'error']
['t', 'a', 'e', 'h', 'e', 'e']
[(0, 0), (0, 1), (0, 2), (0, 3), (1, 0), (1, 1), (1, 2), (1, 3), (2, 0), (2, 1), (2, 2), (2, 3)]