[python] zip, map, lambda, list

a = [1,2,3,4,5]

b = ['a','b','c','d','e']

for x,y in zip (a,b):

    print (x, y)

--------------------

1 a

2 b

3 c

4 d

5 e

----------------------------------------

import numpy as np

def func(x):

   return x * 2

b = map(func, [1, 2, 3, 4])

for x in b:

    print(x)

--------------------

2

4

6

8

* map 오브젝트는 리스트 같지만 원소에 직접 접근은 불가

* b[0] 사용 불가

----------------------------------------

a = lambda x, y: x * y

print(a(3, 4))

--------------------

12

----------------------------------------

import numpy as np

k =[

[11,12,13,14,15,16],

[21,22,23,24,25,26],

[31,32,33,34,35,36],

[41,42,43,44,45,46],

[51,52,53,54,55,56]

]

a = np.array(k)

print(a[::2,1:3:)])

--------------------

[[12 13]

 [32 33]

 [52 53]]

* a[start : end : step] // row에 적용

* a[start : end : step, start, end] // row, column에 적용