< Tanzhou Education >-python Learning notes @ Basic data type

python basic data with Ganso and dictionaries

Ganso (tuple) is the basic data type of Python, with () means that elements are separated by ', ', and once created, the progenitor cannot be changed

In []: s = (' stone ', ' stone ', ' Cathy ')  # # #元祖可以有重复元素In [[]: sout[46]: (' stone ', ' stone ', ' Cathy ') in []: S.count (' St One ')  # # Element Count out[47]: 2In [0In]: S.count (' s ')  # # #没有的话返回0Out []: [in]: S.index (' Stone ')  # #查找索引Out [49]: 0In []: S.index (' Stone ', 1)  out[50]: 1

Dictionary (dict) is a data type consisting of key-value pairs, which is faster than a dictionary lookup compared to other data types. Dictionaries are not sorted by default (no sorting required), and value is found based on key.

in [74]: ditout[74]: {' Age': 18,'Marry':'No',' Work':'Yes'}#Increase#1
In []: dit[' Book'] ='Note' ##增加元素In [76]: ditout[76]: {' Age': 18,' Book':'Note','Marry':'No',' Work':'Yes'}
#2In [[Dit.update]: {' Station':'Quanta'} # # # Update a dictionary type in [78]: ditout[78]: {' Station':'Quanta',' Age': 18,' Book':'Note','Marry':'No',' Work':'Yes'}
# #3生成一个字典

in [+]: Dit.fromkeys ([1,2,2,3,4],3)  # # # # # # # # # # # # # # # # # # # of objects, generate a dictionary out[90]: {1:3, 2:3, 3:3, 4:3} 

#minusIn [Bayi]: Dit.pop (' Station')##删掉一个元素, returns the value of the elementOUT[81]:'Quanta'In [[+]: Dit.popitem ()## Delete a key-value pair and return the deleted key-value pair in the form of a meta-ancestorOUT[82]: (' Work','Yes') in []: Dit.clear ()##清空字典#element Valuein [84]: Dit.items () # #返回一个类似集合类型的对象, typically used to traverse a dictionary key or value out[(+): Dict_items ([(' Age', 18), (' Book','Note'), ('Marry','No')]) in [86]: dit.values () out["Dict_values" ([18,'Note','No'])

#a Set-like object providing a view on D ' s keysin [87]: Dit.keys () out[[+]: Dict_keys ([' Age',' Book','Marry'])

In [the]: Dit.get (' age ')  # # #判断元素是否存在, there is no error, will return none. OUT[91]:

  
  #   Other  in [89]: Dit.copy () # #拷贝Out []: { "  age   ": 18,  " book   ": "  note  , "  marry   ": "  no   " } 
  

#补充: In [107]: ditout[107]: {' age ': + ' book ': ' Note ', ' books ': ' Marry ': ' No '}in [108]: Dit.setdefault (' books ', ') 
   
    # #字典中有这个元素, this element is returned, the dictionary does not change out[108]: 45In [109]: ditout[109]: {' age ': + ' book ': ' Note ', ' books ': ' Marry ': ' No '}in [110] : Dit.setdefault (' name ', ' Stone ') # #字典没有这个元素, returns the value of the set, the dictionary adds out[110]: ' Stone ' in [111]: ditout[111]: {' Age ': ' "book ': ' Note ', ' books ': ' Marry ': ' No ', ' name ': ' Stone '}
   

　　

Dictionary traversal:

For I in dit:  # # High Efficiency
Print I, Dit[i]

For k,v in Dit.items ():  # #效率低
Print K, V

Collection (set) is

< Tanzhou Education >-python Learning notes @ Basic data type