1.数字类型

a.整型num = -1000000000000000000000000000000000000000000000000print(num, type(num))​b.小数num = 3.14print(num, type(num))​c.布尔res = Trueprint(res, type(res), isinstance(res, int))print(3.14 + True)​d.复数num = complex(5, 4)  # 5 + 4jprint(num + (4 + 5j))​重点：数字类型直接的相互转化 a = 10b = 3.74c = Trueprint(int(a), int(b), int(c))print(float(a), float(b), float(c))print(bool(a), bool(b), bool(c))

 

2.字符串类型

a.定义: 可以有多种引号嵌套

例：你是"好学生"

s1 = "你是\"好学生\""

print(s1)

b.可以通过引号的嵌套，使内部不同的引号在不转义的情况下直接输出

例：s2 = '你是"好学生"'print(s2)​例：你是"好学生"，是'我的'3 = """你是"好学生"，是'我的'"""print(s3)

 

3.字符串的常规操作

a.字符串的索引取值: 字符串[index]

正向取值从0编号，反向取值从-1编号

例：s1 = '123abc呵呵'

print(id(s1))  

print(s1[0], id(s1[0])) 

t_s = '1'

print(id(t_s))  # 2217543167200

例：取出c

print(s1[5], s1[-3])

b.字符串拼接

s2 = '你好'

s22 = '帅'

ss2 = s2 + s22

print(ss2, id(s2), id(s22), id(ss2))

如果要拼接其他类型

a = 10

b = "20"

c = True

 

res = "%s%s%s" % (a, b, c)  # 方法1

print(res)

res = str(a) + b + str(c)  # 方法2

print(res)

c.字符串长度

s3 = '12345'

ln1 = s3.__len__()

print(ln1)

ln2 = len(s3)

print(ln2)

c.字符串切片: 取子字符串 - [::] - [start_index:end_index:step]

s4 = '123abc呵呵'

sub_s = s4[0:6:]

print(sub_s)  # 123abc

sub_s = s4[0:6:2]

print(sub_s)  # 13b

sub_s = s4[::-1]

print(sub_s)  # 呵呵cba321

sub_s = s4[-1:-6:-1]

print(sub_s)  # 呵呵cba​

d.成员运算：判断某字符串是否在该字符串中

s5 = '123abc呵呵'

ss5 = '12a'

print(ss5 in s5)  # False

print(ss5 not in s5)  # True​​

# 6.字符串循环(遍历)

s6 = '123abc呵呵'

for v in s6:

print(v)

重要方法

a.索引(目标字符串的索引位置)s1 = '123abc呵呵'print(s1.index('b'))​b.去留白(默认去两端留白，也可以去指定字符)s2 = '***好 * 的 ***'print(s2.strip('*'))​c.计算子字符串个数s3 = '12312312'print(s3.count('123'))d.判断字符串是否是数字:只能判断正整数s4 = '123'print(s4.isdigit())​e.大小写转换s5 = "AbC def"print(s5.upper())  # 全大写print(s5.lower())  # 全小写f.以某某开头或结尾s6 = 'https://www.baidu.com'r1 = s6.startswith('https:')r2 = s6.startswith('http:')r3 = s6.endswith('com')r4 = s6.endswith('cn')if (r1 or r2) and (r3 or r4):    print('合法的链接')else:    print('非合法的链接')    g.替换s7 = 'egon say: he is da shuai b，egon！egon！egon！'new_s7 = s7.replace('egon', 'Liu某')  # 默认替换所有print(new_s7)new_s7 = s7.replace('egon', 'Liu某', 1)  # 替换一次print(new_s7)​h.格式化s8 = 'name：{}，age：{}'print(s8.format('Owen', 18))  # 默认按位置print('name：{1}，age：{1}, height：{1}'.format('Owen', 18))  # 标注位置，一个值可以多次利用print('name：{n}，age：{a}, height：{a}'.format(a=18, n="Zero"))  # 指名道姓4.列表类型定义： a.list中可以存放多个值，可以存放所有类型的数据b.list中有序的，可以通过索引取值常规操作a.索引取值: 列表名[index]s1 = [1, 3, 2] print(s1[0])print(s1[-1])​b.列表运算: 得到的是新lists2 = [1, 2, 3]print(s2 + s2)print(s2 * 2)print(s2)​c.list的长度s3 = [3, 4, 1, 2, 5]print(len(s3))​d.切片：[start_index:end_index:step]s4 = [3, 4, 1, 2, 5]new_s4 = s4[::-1]print(new_s4)new_s4 = s4[1:4:]print(new_s4)new_s4 = s4[-2:-5:-1]print(new_s4)​e.成员运算：ins5 = [3, 4, '1', 2, 5]print('1' in s5)print(1 in s5)print(5 not in s5)​f.循环for v in s5:    print(v, type(v))​ 只打印数字类型的数据for v in s5:    if isinstance(v, int):        print(v, end=' ')​增删改查 a.列表的增删改查ls = [1, 2, 3]​查print(ls)print(ls[1])​增ls.append(0)  # 末尾增print(ls)ls.insert(1, 666)  # 任意index前增print(ls)ls.insert(len(ls), 888)  # insert实行末尾增print(ls)​改ls[1] = 66666print(ls)​删ls.remove(888)print(ls)res = ls.pop()  # 默认从末尾删，并返还删除的值print(res)res = ls.pop(1)  # 从指定索引删除，并返还删除的值print(res, ls)清空ls.clear()print(ls)

 

了解的方法

1）排序: 针对于同类型ls = ['3', '1', '2']ls.sort()  # 默认正向排序print(ls)ls.sort(reverse=True)  # 正向排序结果上翻转，形成倒序print(ls)​2）翻转ls = ['3', '1', '2']ls.reverse()  # 按存储的顺序进行翻转print(ls)​3）计算值的个数 => 列表中可以存放重复数据ls = [1, 2, 1, 2, 3, 1]print(ls.count(1))  # 对象1存在的次数

 

 

 

转载于:https://www.cnblogs.com/haojunliancheng/p/10725828.html