zero,
Variable Type: if the value changes, id unchanged
Immutable type: in the case of changing only, id change
Ordered: Whenever data is indexed ordered
A, int
use
Deposit qq number, phone number, identity card number with no letters
Defined way
age = 18
Variable or immutable
Immutable
Hexadecimal conversion
Other binary decimal turn
# 二进制转十进制 10 —— 1 * (2 ** 1) + 0 * (2 ** 0) # 八进制转十进制 235 —— 2 * (8 ** 2) + 3 * (8 ** 1) + 5 * (8 ** 0) # 十六进制转十进制 217 —— 2 * (16 ** 2) + 1 * (16 ** 1) + 5 * (8 ** 0)int can pass the second parameter, the first parameter represents what band, and then converted into a decimal
- print(int('1100', 2)) - print(int('14', 8)) - print(int('c', 16))Decimal turn the other band
- 十进制转二进制 print(bin(12)) # 0b1100 - 十进制转八进制 print(oct(12)) # 0o14 - 十进制转十六进制 print(hex(12)) # 0xc
Second, the string
description
Defined way
‘ ’ “ ” ‘’‘ ’‘’
Ordered or unordered
Ordered
Variable or immutable
Immutable
Operation and built-in method
By index values
s = 'hello world' print(s[0]) # h print(s[-1]) # dSections (care regardless of tail)
s = 'hello world' print(s[0:5]) # hello print(s[0:10:2]) # hlowr print(s[5:0:-2]) # le print(s[-1:-4:-1]) # dlrlen (count the number of characters)
s1 = ' ' print(len(s1)) # 2in, not in (determined whether there is a character string in a large string)
print('a' in 'abcd') # Truestrip (left and right sides of the character string removed)
strip() # 默认去除字符串首位的空格 name1 = ' byx ' print(name1.strip()) # byx name2 = '$by$x$' print(name2.strip('$')) # by$x 中间的符号不会去除 print(name2.lstrip('$')) # by$x$ print(name2.rstrip('$')) # $by$xsplit (the string into a list)
data = 'byx|18|male' print(data.split('|')) # ['byx', '18', 'male'] 切分成列表 print(data.rsplit('|', 1)) # ['byx|18', 'male'] 从右边切一个'|'for loop
for i in 'byx': print(i, end=' ') # b y xlower, upper (uppercase, lowercase conversion)
s = 'ByX' print(s.lower()) # byx print(s.upper()) # BYX print(s) # ByX s 本身没变startswith, endswith (first determination)
s = 'byx' print(s.startswith('b')) # True print(s.endswith('x')) # Truejoin (mosaic)
user_list = ['byx', '18', 'male'] res = '|'.join(user_list) print(res) # byx|18|malereplace (replace)
str = 'Rome was not built in one day' res = str.replace('day', 'month') print(res) # Rome was not built in one month print(str) # Rome was not built in one day 原字符串没变isdigit (determined whether the input digital)
age = input('请输入年龄') if age.isdigit(): age = int(age) else: print('请输入数字')find, index (look for location)
s = 'Rome was not built in one day' print(s.find('was')) # 5 返回所在位置 print(s.find('xxx')) # -1 找不到时，返回 -1 print(s.find('was', 0, 5)) # -1 通过索引限制查找范围，顾头不顾尾 print(s.find('was', 0, 5)) # 5 只有找到整个‘was’时，才不返回-1，并返回5 print(s.index('was', 0, 5)) # 报错 找不到值报错 print(s.index('was', 0, 8)) # 5 只有找到整个‘was’时，才不报错，并返回5count (count the number of occurrences)
s = 'Rome was not built in one day' print(s.count('o')) # 3center, ljust, rjust, zfill (center filling, filling the left and right filling)
s = 'byx' print(s.center(7, '*')) # **byx** 居中填充，一共7位字符 print(s.ljust(7, '*')) # byx**** 左移后填充，一共7位字符 print(s.rjust(7, '*')) # ****byx 右移后填充，一共7位字符 print(s.zfill(7)) # 0000byx 左边用0填充，一共7位字符expandtabs (changing the number of key spaces table)
s = 'b\tyx' print(s) # b yx print(s.expandtabs(10)) # b yx # table键变为10个空格captalize, swapcase, title
s = 'RoMe waS nOt BuILT in ONe daY' print(s.capitalize()) # Rome was not built in one day 字符串首字母大写 print(s.swapcase()) # rOmE WAs NoT bUilt IN onE DAy 大小写转换 print(s.title()) # Rome Was Not Built In One Day 所有单词首字母大写
Third, the list
Definitions: [] and storing a plurality of arbitrary elements, separated by commas
l = list('abc') l1 = list({'name': 'byx', 'age': 18}) print(l) # ['a', 'b', 'c'] print(l1) # ['name', 'age'] # 内部是for循环Variable or immutable
Variable Types
Ordered or unordered
Ordered
Operation and built-in method
By index values (Forward + Reverse Access Access)
l = [1, 2, 3, 4] print(l[2]) # 3 l[0] = 5 print(l) # [5, 2, 3, 4] 可以通过索引修改元素Sections (care regardless of tail)
l = [1, 2, 3, 4] print(l[0:4:1]) # [1, 2, 3, 4] print(l[0::]) # [1, 2, 3, 4] 默认取到最后，默认步长为1 print(l[5::-1]) # [4, 3, 2, 1]len (length)
l = [1, 2, 3, 4] print(len(l)) # 4in and not in (the members of calculation)
l = [1, 2, 3, 4] print(5 in l) # Falseappend, insert, extend (add elements)
l = [1, 2, 3, 4] l.append(5) print(l) # [1, 2, 3, 4, 5] 尾部添加一个元素 l1 = [1, 2, 3, 4] l1.insert(2, 5) print(l1) # [1, 2, 5, 3, 4] 通过索引在任意位置添加一个元素 l1 = [1, 2, 3, 4] l2 = [5, 6] l1.extend(l2) print(l1) # [1, 2, 3, 4, 5, 6] 列表拼接 l3 = [1, 2, 3, 4] l3.extend([5,]) print(l3) # [1, 2, 3, 4, 5] 内部是for循环，参数要传可迭代对象del, pop, remove (delete)
l = [1, 2, 3, 4] del l[2] # del 按照索引删除，适用于所有的删除操作 无返回值 print(l) # [1, 2, 4] del l # 删除列表 l = [1, 2, 3, 4, 5] l.pop() print(l) # [1, 2, 3, 4] 尾部弹出一个参数 res = l.pop() print(res) # 4 弹出的元素就是返回值 print(l) # [1，2, 3] res1 = l.pop(1) print(res1) # 2 可以按照索引指定弹出元素 l = [1, 2, 3, 4] l.remove(3) print(l) # [1, 2, 4] 指定删除元素，无返回值count (Count)
l = ['a', 'b', 1, 3, 3] print(l.count(3)) # 2 print(l.count('c')) # 0clear (empty)
l = [1, 2, 3, 4] res = l.clear() print(l) # [] print(res) # None 列表被清空sort, reverse (sort and reverse)
l = [2, 1, 5, 4, 3] l.sort() print(l) # [1, 2, 3, 4, 5] l = [2, 1, 5, 4, 3] l.sort(reverse=True) print(l) #[5, 4, 3, 2, 1]
Queue and Stack
Queue (FIFO)
l1 = [] # 先进 l1.append('a') l1.append('b') l1.append('c') # 先出 print(l1.pop(0)) # a print(l1.pop(0)) # b print(l1.pop(0)) # cStack (last out)
l1 = [] # 先进 l1.append('a') l1.append('b') l1.append('c') # 先出 print(l1.pop()) # c print(l1.pop()) # b print(l1.pop()) # a