Python3基礎——序列類型
阿新 • • 發佈：2017-09-07
nat copy operation after max not 下標 元組 rabl
開頭寫給自己，To Myself：
很久以來，都想要學習一門編程語言，從去年選擇了python開始，反反復復重新開始了N多遍，每一次不會超過倆星期。昨天無意間翻開自己去年記的學習筆記，不禁感嘆想當年我曾那麽用功，卻未能堅持下來，著實可惜。這一次，我告訴自己，最後一次機會，必須堅持到底！must。。。。。。
Sequence Types — list, tuple, range
Common Sequence Operations
| Operation | Result | Notes |
|---|---|---|
| x in s | True if an item of s is equal to x, else False——關系操作符 |
(1) |
| x not in s | False if an item of s is equal to x, else True——關系操作符 | (1) |
| s + t | the concatenation of s and t——連接操作符 | (6)(7) |
| s * n or n * s | equivalent to adding s to itself n times——重復操作符 | (2)(7) |
| s[i] | ith item of s, origin 0——獲取下標位i的元素，下標從0開始 | (3) |
| s[i:j] | slice of s from i to j——切片拷貝 | (3)(4) |
| s[i:j:k] |
slice of s from i to j with step k | (3)(5) |
| len(s) | length of s | |
| min(s) | smallest item of s | |
| max(s) | largest item of s | |
| s.index(x[, i[, j]]) |
index of the first occurrence of x in s (at or after index i and before index j) 元素x在s中最早出現的位置下標，可以設置下標所在範圍的起始位置 |
(8) |
| s.count(x) | total number of occurrences of x |
Immutable Sequence Types
hash()
Mutable Sequence Types
| Operation | Result | Notes |
|---|---|---|
| s[i] = x | item i of s is replaced by x | |
| s[i:j] = t | slice of s from i to j is replaced by the contents of the iterable t | |
| del s[i:j] | same as s[i:j] = [] | |
| s[i:j:k] = t | the elements of s[i:j:k] are replaced by those of t | (1) |
| del s[i:j:k] | removes the elements of s[i:j:k] from the list | |
| s.append(x) | appends x to the end of the sequence (same as s[len(s):len(s)] = [x]) | |
| s.clear() | removes all items from s (same as del s[:]) | (5) |
| s.copy() | creates a shallow copy of s (same as s[:]) | (5) |
| s.extend(t) or s += t | extends s with the contents of t (for the most part the same as s[len(s):len(s)] = t) | |
| s *= n | updates s with its contents repeated n times | (6) |
| s.insert(i, x) | inserts x into s at the index given by i (same as s[i:i] = [x]) | |
| s.pop([i]) | retrieves the item at i and also removes it from s | (2) |
| s.remove(x) | remove the first item from s where s[i] == x | (3) |
| s.reverse() | reverses the items of s in place | (4) |
Lists
1、創建列表的方法：
- Using a pair of square brackets to denote the empty list: []
- Using square brackets, separating items with commas: [a], [a, b, c]
- Using a list comprehension: [x for x in iterable]
- Using the type constructor: list() or list(iterable)
list(‘abc‘) returns [‘a‘, ‘b‘, ‘c‘]
list( (1, 2, 3) ) returns [1, 2, 3]
2、除了以上方法外，列表還支持sort()方法
sort(*, key=None, reverse=None)
對列表進行排序，默認是按照從小到大的順序排列
Tuples
1、創建元組的方法：
- Using a pair of parentheses to denote the empty tuple: ()
- Using a trailing comma for a singleton tuple: a, or (a,)
- Separating items with commas: a, b, c or (a, b, c)
- Using the tuple() built-in: tuple() or tuple(iterable)
For example, tuple(‘abc‘) returns (‘a‘, ‘b‘, ‘c‘) and tuple( [1, 2, 3] ) returns (1, 2, 3).
註意：當你要創建的元組只有一個元素時，必須帶逗號
Ranges
代表一組不可變的數字序列，主要用於for循環
class range(stop)
class range(start, stop[, step])
參數必須為整數，step步幅默認為1，start開始參數默認為0、
>>> list(range(10))
[0, 1, 2, 3, 4, 5, 6, 7, 8, 9]
>>> list(range(1, 11))
[1, 2, 3, 4, 5, 6, 7, 8, 9, 10]
>>> list(range(0, 30, 5))
[0, 5, 10, 15, 20, 25]
>>> list(range(0, 10, 3))
[0, 3, 6, 9]
>>> list(range(0, -10, -1))
[0, -1, -2, -3, -4, -5, -6, -7, -8, -9]
>>> list(range(0))
[]
>>> list(range(1, 0))
[]
Python3基礎——序列類型