Python3基礎——序列類型

標籤：mutable   example   body   clear   逗號   singleton   create   sort   關係   

 開頭寫給自己，To Myself：

很久以來，都想要學習一門程式設計語言，從去年選擇了python開始，反反覆複重新開始了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，不禁感歎想當年我曾那麼用功，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——關係操作符	(1)
x not in s	False if an item of s is equal to x, else True——關係操作符	(1)
s + t	the concatenation of s and t——串連操作符	(6)(7)
s * n or n * s	equivalent to adding s to itself n times——重複操作符	(2)(7)
s[i]	ith item of s, origin 0——擷取下標位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，可以設定下標所在範圍的起始位置	(8)
s.count(x)	total number of occurrences of x in s——元素x在序列s中出現的次數

 

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、建立列表的方法：

• 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，列表還支援sort()方法

　　sort(*, key=None, reverse=None)

       對列表進行排序，預設是按照從小到大的順序排列

Tuples

1、建立元組的方法：

• 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). 

注意：當你要建立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迴圈

class range(stop)

class range(start, stop[, step])

參數必須為整數，step步幅預設為1，start開始參數預設為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