• python3的字符串:

　　1.文本字符串(str)---->unicode

'' "" ''' ''' str()

　　2.二進制字符串(bytes)

b'' b"" b''' ''' bytes()

　　3.編碼:

str--->bytes string.encode(encoding = 'utf-8')

　　4.解碼:

bytes--->str bytestring.decode(encodeing = 'utf-8')

　　5.練習

s = 'python是最好的語言' bs = s.encode() print(type(bs)) print(bs)bs2 = bytes(s, encoding='utf-8') print(type(bs2)) print(bs2)s1 = bs2.decode() print(type(s1)) print(s1)s2 = str(bs2, encoding='utf-8') print(type(s2)) print(s2)

• 字符串方法補充

# 居中填充 s = 'python' s = s.center(20, '-') print(s) # 統計出現個數 print(s.count('th', 0, 3)) # 找到子串 '-------python-------' ind = s.find('th') print(ind) # 按進制輸出 s = '{:b}'.format(10) print(s)s = '{:o}'.format(10) print(s)s = '{:x}'.format(10) print(s)import random # 字符串拼接 s = 'beautiful' l = list(s) random.shuffle(l) s = ''.join(l) print(s)s = ''.join(('haha', 'hehe', 'hihi')) print(s)s = ','.join('hello') print(s) # 替換 s = s.replace(',', '.') print(s) # 切割 res = s.split('.') print(res)

• 深復制和淺復制

　　import copy　

# 對于非復合類型 深復制和淺復制無差別 a = 10 b = copy.copy(a) print(id(a)) print(id(b)) a = 20 print(a, b)# 對于可變復合類型 淺復制不會復制子對象,而深復制會 a = [1,2,[100, 200]] b = copy.copy(a) print(id(a)) print(id(b)) a[0] = 110 print(a) print(b) a[2][1] = 222 print(a) print(b)b = copy.deepcopy(a) print(id(a)) print(id(b)) a[0] = 1 print(b) a[2][1] = 333 print(a) print(b)print(id(a[2])) print(id(b[2]))

• 列表生成式

l = []for i in range(100):if i % 2 == 0:l.append(i) print(l)l = [i*i for i in range(100) if i % 2 == 0] print(l) ''' 練習1:有字符串s1 = 'ABC' s2 = 'xyz' 生成一個列表，列表中的元素是['Ax', 'By', 'Cz'] ''' l = [x+y for x in 'ABC' for y in 'xyz'] print(l)s1 = 'ABC' s2 = 'xyz' l = [s1[i]+s2[i] for i in range(len(s1))] print(l)''' 練習2:有列表l = ['Hello', 'EVERYone', 'goOd', 'AFTErNooN']使用一條語句將列表中變成由所有小寫字母組成 ''' l = ['Hello', 'EVERYone', 'goOd', 'AFTErNooN'] l = [x.lower() for x in l] print(l)

• 生成器

l = [i for i in range(100)] print(l)　 # 生成器：節省空間 g = (i for i in range(100)) print(g)print(next(g)) print(next(g))for x in g:print(x, end=' ') print()

• 字典(dict):

# 定義 d1 = {'name':'python', 'age':20} print(type(d1)) print(d1)d2 = dict(name='python', age=20) print(type(d2)) print(d2)d3 = dict([('name', 'python'), ('age', 20)]) print(type(d3)) print(d3)d4 = dict(zip(['name', 'age'], ['python', 20])) print(type(d4)) print(d4)# 通過key得到成員: key唯一的,不可變的 print(d4['name'])d4['name'] = 'guido' print(d4)# 獲得所有的key, values, item print(d4.keys())print(d4.values())print(d4.items())# 遍歷 for k in d4.keys():print(d4[k])for k, v in d4.items():print(k, v)for k in d4: # keyprint(k)# 增加 d4['height'] = 180 print(d4)d4.update(id=5, score=100) print(d4)# 刪除 d4.pop('id') print(d4)

• 集合(set):無序的不重疊的可變的

　　去除重復

# 定義 st = {1,2,3,4} print(type(st)) print(st)# 去重 l = [1,2,3,3,2,34,1,23] l = list(set(l)) print(l)for i in st:print(i)st.add(100) print(st)st.pop() print(st)st.remove(100) print(st)st2 = {2,1,8,9,4} print(st & st2) # 交集 print(st | st2) # 并集 print(st - st2) # 差集 print(st ^ st2) # 交叉差集

　　

轉載于:https://www.cnblogs.com/ZHang-/p/10084454.html

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