Python Lists 강좌 ( 원문, google.com )

Python Lists , 리스트

원문에서 제공하는 예제는 실제 실행시에, 예약어등의 사용으로 warning과 error가 발생하므로 수정해서 실행을 해야 한다. 이 실행 결과를 정리한다.

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## Python Lists , 리스트 기본

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# Lists work similarly to strings - use the len() function and square brackets[] 

# to access data, with the first element at index 0

colors = ['blue', 'blue', 'green']

print (colors[0])  ## blue 
print (colors[2])  ## green 
print (len(colors)) ## 3  
 

# Assignment with an = on lists doest not make a copy. 복사 금지

# Instead, assignment makes the two variables point to the one list in memory

b = colors ## Does not copy the list

print(b)  ## ['blue', 'blue', 'green'] 

empty_list = [] ## is just an empty pair of brackets []

yield_list = [1,2] + [3, 4] ## The '+' works to append two lists
print(yield_list) ## [1, 2, 3, 4] 

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## FOR and IN , 생성자 For

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# Python's *for* and *in* constructs are extremely useful, 

# and the first use of them we'll see is with lists.

squares = [1, 4, 9, 16]
total_value = 0
# The *for* construct - for var in list 
#    is an easy way to look at each element in a list.
#    Do not add or remove from the list during iteration.
for num in squares:
  total_value += num
print( total_value ) ##30

# The *in* construct on ite own is an easy way to test if an element appears

# in a list(or other collection) - value in collection - tests if the value is

# in the collection, returning True/False

name_list = ['larry', 'curly', 'moe']
if 'curly' in name_list:
  print('yay')

# test_strings = 'abcd'
# for ch in test_strings:
#   print(ch) ## a b c d

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## Range , 범위 ( 0 ~ n-1 ) 

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# The range(n) function yields the numbers 0,1, ... n-1 and range(a,b) returns

# a, a+1, ... b-1 up to but not including the last number.

# for i in range(100):
#   print(i)

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## While Loop, 반복 While

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# Python also has the standard while-loop, and the *break* and *continue* statements work

# as in C++ and Java, altering the course of the innermost loop.

i = 1
a = 'abc'
while i < len(a):
  print (a[i]) ## b
  i = i + 3

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## List Methods , 함수들

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# Here are some other common list methods.

# list.append(elem) : adds a single element to the end of the list

# list.insert(index, elem) : inserts the element at the given index

# list.extend(list2) : adds the elements in list2 to the end of the list

# list.index(elem) : searches for the given element from the start of the list and returns its index

# list.remove(elem) : searches for the first instance of the given element and removes it

# list.sort() : sorts the list in place(does not return it)

# list.reverse() : reverses the list in place(does not return it)

# list.pop(index) : removes and returns the element at the given index

str_list = ['larry', 'curly', 'moe']
str_list.append('shemp')
str_list.insert(0,'xxx')
str_list.extend(['yyy', 'zzz'])
print(str_list) ## ['xxx', 'larry', 'curly', 'moe', 'shemp', 'yyy', 'zzz']
print(str_list.index('curly')) ## 2

str_list.pop(1)
print(str_list) ## ['xxx', 'curly', 'moe', 'shemp', 'yyy', 'zzz']

# common error 

# : note that the above methods do not *return* the modified list, 

#   they just modify the original list

num_list = [1, 2, 3]
print(num_list.append(4)) ## None
num_list.append(4)
print(num_list) ## [1, 2, 3, 4, 4]

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## List Build up, 생성하기

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# One common pattern is to start a list a the empty list[],

# then use append() or extend() to add elements to it

empty_list = []
empty_list.append('a')
empty_list.append('b')
print(empty_list) ## ['a', 'b']

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## List Slices, 자르기 [start:end:step]

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# Slices work on lists just as with strings, and can also be used to change

# sub-parts of the list

char_list = ['a', 'b', 'c', 'd']
print(char_list[1:-1]) ## ['b', 'c']
print(char_list[:]) ## ['a', 'b', 'c', 'd'] 
print(char_list[1:2]) ## ['b']
char_list[0:2] = 'z' 
print(char_list) # ['z', 'c', 'd'] 

원본 

https://developers.google.com/edu/python/lists