function
Function is used to: implement a function, function as a tool to understand the problems encountered can use this tool to take over
Benefits function: function more convenient, multiplexing, can be used in multiple scenes
Function definition: def function name (parameter)
Using the Recall function to solve the circle of pi
def get_pi(num):
import random
count = 0
for i in range(num):
x, y = random.random(), random.random()
dist = pow((x - 0) ** 2 + (y - 0) ** 2, 0.5)
if dist < 1:
count += 1
print(4 * count / num)
get_pi(10)
get_pi(100)
get_pi(1000)
get_pi(10000)
get_pi(100000)
Function into a function with parameters and return value of the function
def add_sum(num):# num就是一个参数
count = 0
for i in range(1, num):
count += i
return count #返回值, 是count
res1= add_sum(101) #101就是参数的值传给函数的参数
print('res1:',res1)
res2 = add_sum(1001)
print('res2:',res2)
res3 = add_sum(10001)
print('res3:',res3)set
What is the set: A collection is a set of data
Defining a set (the set of definitions can be set (), you can also be defined directly enclosed by {})
s1={'nick','handsome',121,11}#
s2 = set('nick') # iterable(序列类型)
s3 = set(['1', 2, 3])
#输出结果{1.0, 'nick', 'dsb', 1231, 'wuhao', 'handsome'}
{'n', 'i', 'c', 'k'}
{'1', 2, 3}A set of operators
| Operators and Applications | description |
|---|---|
| S | T | It returns a new set, comprising all of the elements in the set S and T |
| S - T | It returns a new set, comprising a set of elements in S but not in T |
| S & T | It returns a new collection, including at the same time elements of the set S and T |
| S ^ T | It returns a new set, comprising a set S and T non-identical elements |
| S <= T或S < T | Returns True / False, determining the subset of the relationship between S and T |
| S >= T或S > T | Returns True / False, comprising determining the relationship between S and T |
Processing methods for the collection
| The method of operation or function | description |
|---|---|
| S.add(x) | If x is not in the set S, the increased S x |
| S.discard(x) | S removal elements x, if x is not in the set S, not given |
| S.remove(x) | S removal elements x, if x is not in the set S, the abnormality is generated KeyError |
| S.clear() | Remove all elements of S |
| S.pop() | Returns a random element of S, S update, if S is empty produce abnormal KeyError |
| S.copy() | Returns a copy of the set S |
| only the (S) | Returns the number of elements in the set S |
| x in S | Analyzing elements S x, x in the set S, returns True, otherwise return False |
| x not in S | Analyzing elements S x, x S is not set, it returns False, otherwise True |
| set(x) | The other type of variable x into a set type |
sequence
There will be a serial number sequence, the same as the index,
Type sequence, with an index of the data type is: character, a list, ancestral
Comma-separated list of intermediate brackets
E.g:
lt = ["nick","handsome",1,1]
print(lt)
A list of defined functions
| Function or method | description |
|---|---|
| ls[i] = x | Alternatively the i-th list element is ls x |
| ls[i: j: k] = lt | After replacing the list with ls lt element sections corresponding sublist |
| ls the [i] | I deleted the first element of the list ls |
| del ls[i: j: k] | Delete the first list ls i to j-k is a long step to the elements |
| ls += lt | Ls update list, the list will be added to the list of elements lt ls of |
| ls = n * | Update the list ls, whose elements are repeated n times |
List of definitions
| Function or method | description |
|---|---|
| ls.append(x) | In the list of the last ls add an element x |
| ls.clear() | Delete all of the elements in the list ls |
| ls.copy() | Generate a new list, all elements assigned ls |
| ls.insert(i,x) | Adding elements x i of the list of ls |
| ls.pop(i) | The i-th position of the list element ls removed and remove the element |
| ls.remove(x) | The first element in the list that appears in x delete ls |
| ls.reverse() | Ls will list the elements in reverse |
# 清除
lt.clear()
#
lt2 = lt.copy()
# 排序
lt = [1,3,2,100,4,5]
lt.sort()
print(lt)
# 翻转
lt.reverse()
print(lt)
# 元组
# 元组就是把列表的中括号换成小括号,然后他没有内置方法
lt = [1,3,2,100,4,5]
# 只可取不可更改
tu = (1,3,2,100,4,5)
print(tu[0])Basic statistical methods
A set of data input by the user (a user input), and the median calculation data, mean, variance, and other operations required o
nums = []
while True:
num1 = input('请输入你需要输入的数字(输入 q 退出):')
if num1 == 'q':
break
nums.append(int(num1))
def get_median(nums): # ['123', '32', '123', '234']
# 0 1 2 3
nums.sort()
nums_len = len(nums)
if nums_len % 2 == 0:
print((nums[int(nums_len / 2 - 1)] + nums[int(nums_len / 2)]) / 2)
else: # ['123', '32', '123'] # 1
print(nums[nums_len // 2]) # ['123', '32', '123','123', '32', '123','123'] # 3
# get_median(nums)
def get_sum(nums): # ['123', '123', '213', '234', '98234']
count = 0
for i in nums:
count += int(i)
return count
# count = get_sum(nums)
# print('count:',count)
def get_average(nums):
count = get_sum(nums)
average_count = count/len(nums)
return average_count
# average_count = get_average(nums)
# print(average_count)
def get_variance(nums):
average_count = get_average(nums)
variance_count = 0
for i in nums:
variance_count += pow(i-average_count,2)
return variance_count
variance_count = get_variance(nums)
print(variance_count)Dictionary Type
Dictionary definition of the type can also be defined directly dict
d = { "China": "Beijing", "America": "Washington"}
Dictionary handler method
| Function or method | description |
|---|---|
| of d [k] | D button to delete the dictionary data corresponding to the value k |
| k in d | Determine whether the key k d in the dictionary, if in return True, otherwise False |
| d.keys() | Return all the key information in the dictionary d |
| d.values() | All the information returned value in the dictionary d |
| d.items() | D return dictionary of all the key information |
A dictionary manipulation functions and methods
| Function or method | description |
|---|---|
| d.get(k, ) | Bond k is present, the corresponding value is returned, the return value is not |
| d.pop(k, ) | Bond k is present, the corresponding values are fetched, the return value is not |
| d.popitem () | D taken randomly from the dictionary in a key-value pairs in the form of tuples to return |
| d.clear() | Remove all key-value pairs |
| len (d) | Returns the number of elements in the dictionary d |
jieba Hyogo
jieba word generally used for library
Learn three major statement
# 马尔可夫模型(两层)
res = jieba.lcut('中华人民共和国是一个伟大的国家') # 第一个就是尽量长,主要掌握这一个
print(res)
res = jieba.lcut_for_search('中华人民共和国是一个伟大的国家') # 第二个就是把第一个的长的单词继续切
print(res)
res = jieba.lcut('中华人民共和国是一个伟大的国家',cut_all=True) # 把所有的可能全部切出来
print(res)