一、PRINT FORMATTED OUTPUT 1、%形式输出

1.1 匹配字符，整数，浮点数(含精度)，%类似转义

print("my name is %s，age %d height %.2fm learning python progress is 3%%s." %(burton,33,1.785))

output result:

my name is burton，age 33 height 1.78m learning python progress is 3%s.

1.2 指定占位符宽度、左右对齐和填充

print ("Name:%-10s Age:%08d Height:%8.2f"%("Aviad",25,1.833)) 

output result:

Name:Aviad      Age:00000025 Height:    1.83

1.3 有以下格式符

%s   字符串 (采用str()的显示)

%r   字符串 (采用repr()的显示)

%c   单个字符

%b   二进制整数

%d   十进制整数

%i   十进制整数

%o   八进制整数

%x   十六进制整数

%e   指数 (基底写为e)

%E   指数 (基底写为E)

%f   浮点数

%F   浮点数，与上相同

%g   指数(e)或浮点数 (根据显示长度)

%G   指数(E)或浮点数 (根据显示长度)

%%   字符"%"

2、format形式输出

2.1 位置传参

li = [burton,18,178]

print(my name is {} ,age {}.format(burton,18))

print(my name is {1} ,age {0}.format(18,burton))

print(my name is {0} ,age {1}.format(*li))

print(name is {0[0]} age is {0[1]}.format(li))

output result:

my name is burton ,age 18

2.2 关键字传参

hash = {name:burton,age:18,heigth:178}

print(my name is {name},age is {age}.format(name=burton,age=18))

print(my name is {name},age is {age}.format(**hash))

output result:

my name is burton ,age 18

2.3 填充与格式化

print({0:*>8}.format(18))   ##右对齐

******18

print({0:*<8}.format(18))   ##左对齐

18******

print({0:*^8}.format(18))  ##居中对齐

***18***

2.4 精度与进制

print({0:.2f}.format(1/3))  # 0.33

print({0:b}.format(10))     # 1010

print({0:o}.format(10))     # 12

print({0:x}.format(10))     # a

print({:,}.format(1234567890)) # 1,234,567,890

3、GIve some examples

e.g.1

lst=[(lily,23,female),(burton,34,male)]

for tup in lst:

    print(*tup,sep=!,end=*)           

output result:

lily!23!female*burton!34!male*

二、LOGICAL OPERATION

Priority level: not > and > or

print(True or False)                    # True

print(2 and 3)                             # 3

print(2 or 1 < 3)                          # 2

print(3 < 1 or 2 and 1)                # 1

print(not 2 > 4 and 5 or 3 < 2 and 3)  # 5

三、DATATYPE 1、Integer

print(int(5.1))        # 5

print(int(5))        # 5

i = 5

print(i.bit_length())  # 3  Turn binary digits  101

2、Strings

2.1 字符串常用函数

s = sA3 u43

s0 = s.capitalize()           # Sa3 u43

s1 = s.title()                    # Sa3 U43

s2 = s.replace(s,w)      # wA3 u43

s31 = s.find(3,3,)           # 6   find index,from 3 to end

s32 = s.find(3,3,6)         # -1  last index

s33 = s.find(3)               # 2   times

s4 = s.center(20,*)        # ******sA3 u43*******

s5 = s.count(3,1,4)        # 1  count substr,index from 1 to 4

s6 = s.index(u,1,5)        # 6

s7 = s.split()                   # [sA3, u43] change to list，default delimiter space

s8 = s.strip(3)                 # sA3 u4  Remove both sides matching characters，default space

s9 = s.startswith(u,4,)   # True  return Boolean type

s10 = s.endswith(2)      # False

s11 = s.upper()              # SA3 U43

s12 = s.lower()               # sa3 u43

s13 = #.join(s)              # s#A#3# #u#4#3

2.2 字符串切片

s = abcD1efs2

s0 = s[:]                         # abcD1efs2

s1 = s[0:]                       # abcD1efs2

s2 = s[4:-1]                    # 1efs

s3 = s[4:-1:2]                 # 1f

s4 = s[4::-1]                   # 1Dcba

s5 = s[6:0:-2]                 # f1c

s6 = s[s.index(c):0:-1]  # cb

s7 = s[0:6:-2]                 # None

3、List

3.1 列表增删改查

li = [alex,wusir]

3.1.1 增加列表

li.append(burton)        # [alex, wusir, burton]

li.insert(1,lina)             # [alex, lina, wusir]

li.extend(boy)              # [alex, wusir, b, o, y]

3.1.2 删除列表

name = li.pop(0)

print(name,li)               # alex [wusir]   默认删除最后一个

li.remove(alex)           # [wusir]     按元素去删除

li.clear()                       # 清空

del li                            # 删除列内容和定义

del li[1:]                       # [alex]  切片去删除

3.1.3 修改列表

li[0] = [1,burton]        # [[1, burton], wusir]

li[0:2] = [1,burton,jm] # [1, burton,jm]

3.1.4 查找列表

for i in li:

    print(i)                # alex wusir

print(li[0:2])              # [alex, wusir]

3.2 公共方法

li = [1,5,6,2,5]

l = len(li)                        # 5

num = li.count(5)           # 2

num = li.index(5)           # 1

l1 = li.sort()                    # None 顺序，只针对原列表

l2 = li.reverse()              # None 倒序，只针对原列表

lst = [alex,wusir]

s = +.join(lst)                # 得到字符串 alex+wusir

3.3 特殊列表

for i in range(2,5)           # 2 3 4

for i in range(3)              # 0 1 2

for i in range(0,10,3)      # 0 3 6 9

for i in range(7,0,-2)      # 7 5 3 1

3.4 枚举

list1 = [1,2,33]

for i, v in enumerate(list1):

    print(i, ":", v)

result：

0 : 1

1 : 2

2 : 33

3.5 遍历所有的元素

li = [1,2,3,5,alex,[2,3,4,5,taibai],afds]

for i in range(len(li)):

    if type(li[i]) == list:

#   if isinstance(li[i],list):

        for j in li[i]:

            print(j)

    else:print(li[i])

3.6 去重复值：

def del_duplicates(values):

    if len(values) == 0:

         return False

    lst = []

    lst.append(values[0])

    for i in range(1,len(values)):

        if values[i] in lst:

            continue

        else:

            lst.append(values[i])

    return lst

print(del_duplicates([20,30,20,40,30]))

4、tuple（只读列表，可循环查询，可切片，儿子不能改，孙子可能可以改）

tu = (1,alex,[3,4,taibai])

tu[2][2]                    # taibai

tu[2][2]=tu[2][2].upper()   # TAIBAI 转成大写

for i in tu:

    print(i)                # 查看元祖

5、Dictionary

dic1 = {age: 18, name: jin}

5.1 增加字典

dic1[height] = 185                    # 对没有键值添加，有键值的覆盖

dic1.setdefault(weight)             # 没有键值，默认为None

dic1.setdefault(weight,150)      # 位置随机

dic1.setdefault(name,burton)  # 有键值不添加

5.2 删除字典

dic1.pop(age)                       # 18

dic1.pop(sex,None)             # 没key就会报错，避免该问题可设置返回值

dic1.popitem())                     # 随机删除 有返回值 元组里面是删除的键值。

del dic1[name]                    # 删字典内容，如没对应key报错

del dic1                                # 删整个字典

dic1.clear()                          #清空字典

5.3 修改字典

dic1[age] = 16                    # 原来有的key

dic2 = {"name":"alex","weight":75}

dic2.update(dic)                  # 原来有key修改，没有增加

5.4 查找字典

print(dic1.items())                #打印出是个列表

for i in dic1.keys()

for i in dic1.values()

for k,v in dic1.items()

dic1.get(name1,no key)    # 没匹配就返回空，如有第二个参数，返回第二个参数

5.5 例子

def element_times(values):

    if len(values) == 0:

        return False

    dic = {}

    for i in range(0,len(values)):

        if str(values[i]) in dic:

            dic[str(values[i])] += 1

        else:

            dic[str((values[i]))] = 1

    return dic

print(element_times([40,30,30,20,40,30,40]))

output result:

{20: 1, 40: 3, 30: 3}

6、set

set1 = set({1,2,3})

set1 = {1,2,3}                       #元素是不可哈希

6.1 insert set content

set1.add(burton)                 # {1,2,3,burton}

set1.update(abc)                # {1,2,3,abc}

6.2 delete set content

set1.pop()                            # 随机删除

print(set1.pop())                   # 有返回值

set1.remove(2)                    # 按元素

set1.clear()                          # set()

del set1

6.3 intersection and union and so.

set1 = {2,3,4}

set2 = {4,5,6}

print(set1 & set2)                # {4}

print(set1.intersection(set2))    # {4}

print(set1 | set2)                # {2, 3, 4, 5, 6}

print(set2.union(set1))           # {2, 3, 4, 5, 6}

print(set1 ^ set2)                # {2, 3, 5, 6}

print(set1.symmetric_difference(set2))  # {2, 3, 5, 6}

print(set1 - set2)                # {2, 3}

6.4 Give some examples

e.g.1 ### remove duplicate values

li = [1,2,33,33,2,1,4,5,6,6]

set1 = set(li)

li = list(set1)

print(li)

四、FILES 1、read file

The testfile.txt file is stored in abc

e.g.1 # r read mode

f = open(testfile.txt,mode=r,encoding=utf-8)

content = f.read()

print(content)

f.close()                     

# must close the file after used

result: abc

with open(testfile.txt,mode=r,encoding=utf-8) as f:

     print(f.read())          # neednt close the file

output result: abc

e.g.2 # r+b read mode

f = open(testfile.txt,mode=r+b)

content = f.read()

f.close()

print(content)

output result: babc

e.g.3 # 你好 in file

f = open(testfile.txt,mode=r+b)

print(f.read())

f.write(大猛.encode(utf-8))

f.close()

output result: print b\xe4\xbd\xa0\xe5\xa5\xbd ,你好大猛 in file

e.g.4 # r+ read mode,abc in file

f = open(testfile.txt,mode=r+,encoding=utf-8)

content = f.read()

print(content)

f.write(ABC)

f.close()

output result: print abc , abcABC in file

e.g.5 # We change the order of reading and writing,abc in file

f = open(testfile.txt,mode=r+,encoding=utf-8)

f.write(ABC)

content = f.read()

print(content)

f.close()

output result: print None , ABC in file

2、write file

e.g.1 # abc in file

f = open(testfile.txt,mode=r,encoding=utf-8)

f.write(DBA)

f.close() 

result:DBA  # The file content will be recover by DBA

e.g.2 # abc in file

f = open(testfile.txt,mode=w+,encoding=utf-8)

f.write(aaa)

f.seek(0)

print(f.read())

f.close()

result:print aaa,aaa in file

e.g.3 # wbmode

f = open(testfile.txt,mode=wb)

f.write(佳琪.encode(utf-8))

f.close()

result:佳琪 in file

e.g.4 # abc in file

f = open(testfile.txt,mode=a+,encoding=utf-8)

f.write(佳琪)

f.seek(0)            #move cursor position

print(f.read())

f.close()

output result:print abc佳琪，also abc佳琪 in file

3、Other function

print(f.tell())      # tell you where is cursor position

f.truncate(4)

f.readlines()        # Read files line by line

4、 Give some examples

e.g.1

# abc\nABC in file

with open(testfile.txt,mode=r,encoding=utf-8) as f:

      for i in f.readlines()

          print(i)

outputresult:

abc 

ABC

五、FUNCTION 1、Description function

def func():

    You can describe what function is implemented.

    How to use parameter values

    what return

    pass

2、How to use function

e.g.1

def sum(a,b=2,*args):

    total = a +b

    for i in args:

        total += i

    return total

print(sum(1,4,9,10))         #24

print(sum(2))                    #4

e.g.2

def func1(a,b=1,**kvargs):

    print(a,b,kvargs)

func1(3,4,x=4,y=5)           # 3 4 {x: 4, y: 5}

e.g.3

def func2(*args,**kvargs):

    print(args,kvargs)

func2(a,1,x=3,y=2)         # (a, 1) {y: 2, x: 3}

e.g.4

def func3(a,*args):

    total = a

    for i in args:

        total += i

    return total

li = [1,3,5,7,9]

print(func3(*li))             # 25

3、递归函数

e.g.5 #斐波那契数列 1,1,2,3,5,8,13,21,34,55

#mothed 1

def fun(n):

    if n == 1:

        return 1

    if n == 2:

        return 1

    return fun(n-1) +fun(n-2)

print(fun(6))            # 8 这样写效率很差

#mothed 2

def fib(n,a=1,b=1):

    if n==1 : return a

    return fib(n-1,b,a+b)

print(fib(6))              # 8 这样写效率高

4、变量作用域

e.g.6 # nolocal 一般是用在闭包函数里

x = 123

def outer():

    x = 100

    def inter():

        nonlocal x

        x = 200

    inter()

    print(x)

outer()

output result: 200

e.g.7 # global全局变量

x = 123

def testglobal():

    global x

    print(x)

    x = 100

    print(x)

testGlobal()

print(x)

output result:

123

100

100

5、Give some examples

e.g.8 # 登入验证

my_script1.py

def judgment(user,li=[]):

    for i in range(len(li)):

       if user in li[i].keys():

         return 1

    if not user.isalnum() and user[0].isdigit():

         return 2

    return 3

def register(user,pswd,li=[]):

    li.append({user:pswd})

    return li

li = [{lina: 342}, {burton: 223}]

flag = True

i = 0

while i < 3:

    usernm = input("Please enter username:")

    if judgment(usernm,li) == 1:

        print(该账号已被注册，请重新输入账号。)

        i += 1

        continue

    elif judgment(usernm,li) == 2:

        print(输入的账号只能数字和字母，且不能数字开头!)

        i += 1

        continue

    else:

        passwd = input("Please enter password:")

        register(usernm,passwd,li)

        break

else:

    print(你没有机会了！)

print(li)

e.g.9 # 随机数据和字母验证码

# def ger_verif(arg):

#     l=[]

#     for i in range(48,58):

#         l.append(chr(i))

#     for i in range(65,91):

#         l.append(chr(i))

#     for i in range(97,123):

#         l.append(chr(i))

#     lst = random.sample(l,arg)

#     print(.join(lst))

#     return .join(lst)

def ger_verif(arg):

    s=""

    for i in range(0,arg):

        cur = random.randint(0,5)

        if cur > 2:

            cur = chr(random.randint(65,90))

        elif i < 2:

            cur = chr(random.randint(97,122))

        else:

            cur = chr(random.randint(48,57))

        s += cur

    print(s)

    return s

def verification():

    num = 3

    gere = ger_verif(6)

    while num > 0:

        str = input(Please enter code:)

        if len(str) == 0:

            return 0

        if gere.upper() != str.upper():

            num -= 1

            print(Please enter correctly verification!)

        else:

            return 1

    return 0

ret = verification()

print(ret)

六、REGULAR KNOWLEDGE POINT http://tool.chinaz.com/regex/

   测试网站

https://www.regexpal.com/

(正则在线匹配)

1、Cheat Sheet

1.1 Character classes

.                 # any character except newline

\w \d \s       # word, digit, whitespace

\W \D \S     # not word, digit, whitespace

[abc]          # any of a, b, or c

[^abc]        # not a, b, or c

[a-g]          # character between a & g

1.2 Anchors

^abc$        # start / end of the string

\b              # word boundary

1.3 Escaped characters

\. \* \\         # escaped special characters

\t \n \r        # tab, linefeed, carriage return

\u00A9      # unicode escaped

1.4 Groups & Lookaround

(abc)         # capture group

\1              # backreference to group #1

(?:abc)      # non-capturing group

(?=abc)     # positive lookahead

(?!abc)      # negative lookahead

1.5 Quantifiers & Alternation

a* a+ a?    # 0 or more, 1 or more, 0 or 1

a{5} a{2,}   # exactly five, two or more

a{1,3}        # between one & three

a+? a{2,}? # match as few as possible

ab|cd         # match ab or cd

2、 Give some examples

e.g.1

str1 = chinese&people

ret = re.findall((?<=chinese)\Wpeople,str1)        # &people

ret1 = re.findall(chinese\W(?=people),str1)        # chinese&

ret2 = re.findall((?

ret3 = re.findall(chinese\W(?!=man),str1)           # chinese&

ret4 = re.sub(\B(?=(?:\d{3})+(?!\d)),,,1234567890)   #1,234,567,890  ???