Python_Day_03 list, dic, tuple method summary, python_day_03tuple

Python_Day_03 list, dic, tuple method summary, python_day_03tuple

Several data types, dictionaries, lists, and so on are the most common in programming languages. These data types are also available in Python, but some forms are different.In Python, there is another thing called tuple.

 

　　List)

• Initialization list

1 li = list([1,2,3,4])

• You can also directly create

1 li_dir = [42,534,4654,64]

• Append (self, p_object) adds an element at the end of the list. The default value is None.

1 li_append = list([1,2,3,4])2 li_append.append(43)3 print(li_append) # [1, 2, 3, 4, 43]

• Clear (self) clear the Array

1 li_clear = list([1,2,3,4])2 li_clear.clear()3 print(li_clear) # []

• Copy (self) shallow copy (what is the difference with deep copy? We haven't studied it yet)

1 li_copy = list([11,22,33])2 li_copy_copy = li_copy.copy()3 print(li_copy_copy) #[11, 22, 33]

• Count (self, value Returns the number of values in the list. A statistical value must be input. Otherwise, an error is returned.

1 li_count = list([111,222,333,444,111])2 li_counts = li_count.count(11) # 03 print(li_counts)4 li_counts_two = li_count.count(111)5 print(li_counts_two) # 2

• Extend (self, iterable) is equivalent to expansion. The extended parameters must also be lists or tuples. At the same time, they must be extended based on the original list, and the extended data is at the end of the list.

1 li_extend = list ([111,222,333,444,111]) 2 # When the extended parameter is a tuples, if 'is not added to the element,' the extension fails, error 3 li_extend.extend (12,) 4 print (li_extend) # [111,222,333,444,111, 12] 5 li_extend.extend ([12,124, 5, 5]) 6 print (li_extend) # [111,222,333,444,111, 12, 12,124, 3, 4,534, 5, 5]

• Index (self, value, start = None, stop = None) searches for the subscript of an element in the list based on the value.

1 li_index = list ([111,222,333,444,111]) 2 # by default, the entire list is queried. When the first existing value is found, the system returns and does not continue searching for the list elements, if no element exists, 3 li_index_index = li_index.index (111,0, 4) 4 print (li_index_index) #0 is returned.

• Insert (self, index, p_object) insert the specified element under the specified subscript

1 li_insert = list([111,222,333,444,111])2 li_insert.insert(3,'Python')3 print(li_insert) # [111, 222, 333, 'Python', 444, 111]

• Pop (self, index = None) pops up the specified subscript element, and a variable can be defined to receive the pop-up element. the last one is displayed by default. If the list is empty or the subscript exceeds the maximum subscript of the list, an error is returned.

1 li_pop = list([12,4234,3,534,64536])2 li_receive = li_pop.pop(3)3 print(li_pop) # [12, 4234, 3, 64536]4 print(li_receive) # 534

• Remove (self, value) deletes the elements in the list based on the value. If there are multiple Deleted Values in the list, only the first value will be deleted. If the deleted value does not exist, an error will be returned.

1 li_remove = list([11,23213,11,232323242])2 li_remove.remove(11)3 print(li_remove) # [23213, 11, 232323242]

• Reverse (self) Flip list

li_reverse = list([11,23213,11,232323242,'fdsa','rt433',13423])li_reverse.reverse()print(li_reverse) # [13423, 'rt433', 'fdsa', 232323242, 11, 23213, 11]

• Sort (self, key = None, reverse = False) sorting (not much of this study)

Li_sort = list ([4, 6, 2, 1, 7, 9]) li_sort.sort () print (li_sort) # [1, 2, 4, 6, 7, 9] # Keep copy li_sort_y = li_sort [:] li_sort_y.sort () print (li_sort_y) # [1, 2, 4, 6, 7, 9] while retaining li_sort

 

　　Tuple (tuples)

The method is relatively simple, but you must add 'At the end of the Creation.' Only search for kinetic energy, no addition, deletion, and modification are required.

tup = tuple((12,3242,3,4435,43,45,6,12))

• Count (self, value) searches for the number of occurrences of a value in the tuples

tup = tuple((12,3242,3,4435,43,45,6,12))tup_count = tup.count(1) # 0print(tup_count)

• Index (self, value, start = None, stop = None) searches for subscripts based on a specific value in the tuples. The default value is the entire array and you can customize the search range, if it appears multiple times, only the first

tup = tuple((12,3242,3,4435,43,45,6,12))tup_index = tup.index(12)print(tup_index) # 0

 

　　Dict (dictionary)

　　The middle keys in the dictionary cannot be repeated. If repeated, the first occurrence will be overwritten.

dic = {'k1':'v1','k2':'v2','k3':'v3','k1':'v4'} print(dic) # {'k1': 'v4', 'k2': 'v2', 'k3': 'v3'}

• Clear (self) clear all elements in the dictionary

dic_clear = {'k1':'v1','k2':'v2','k3':'v3','k1':'v4'}dic_clear.clear()print(dic_clear) # {}

• Copy (self) Shortest copy (similar to an array, we haven't studied it in depth)

dic_copy = {'k1':'v1','k2':'v2','k3':'v3','k1':'v4'}dic_copy_copy = dic_copy.copy()print(dic_copy_copy) # {'k1': 'v4', 'k3': 'v3', 'k2': 'v2'}

• Fromkeys (* args, ** kwargs) assigns the same value to an array.

dic_keys = dict.fromkeys([1,232,423,43,43],['da','fsda']) # {232: ['da', 'fsda'], 1: ['da', 'fsda'], 43: ['da', 'fsda'], 423: ['da', 'fsda']}dic_keyss = dict.fromkeys([1,232,423,43,43],'da')print(dic_keyss) # {232: 'da', 1: 'da', 43: 'da', 423: 'da'}

• Get (self, k, d = None) returns the value returned based on a key. If no value exists, you can also customize the default value.

dic_get = {'k1':'v1','k2':'v2','k3':'v3','k1':'v4'}dic_get_get = dic_get.get('k1','rookieJX')print(dic_get_get) # v4dic_get_get2 = dic_get.get('k','rookieJX')print(dic_get_get2) # rookieJX

• Items (self returns all elements (all key-value pairs)

Dic_items = {'k1 ': 'v1', 'k2': 'v2', 'k3 ': 'v3', 'k1 ': 'v4'} dic_items.items () print (dic_items) #{'k3 ': 'v3', 'k2': 'v2', 'k1': 'v4 '} note that the returned dynamic, the order is constantly changing.

• Keys (self returns all keys

Dic_keys = {'k1 ': 'v1', 'k2': 'v2', 'k3 ': 'v3', 'k1 ': 'v4'} dic_keys_receive = dic_keys.keys () print (dic_keys_receive) #(['k1 ', 'k3', 'k2']) note that another list is returned here, and an additional definition list is required to receive the return value.

• Pop (self, k, d = None) is not very useful because the dictionary is unordered. If the key value does not exist, there is no default value.

Dic_pop = {'k1 ': 'v1', 'k2': 'v2', 'k3 ': 'v3', 'k1 ': 'v4 '} dic_res = dic_pop.pop ('k10', 100) print (dic_pop) # {'k3': 'v3 ', 'k1': 'v4 ', 'k2 ': 'v2'} does not change the original dictionary. You need to redefine it to accept the data print (dic_res) #100 if the pop-up key-value pair is not specified, the specified value will be returned for a long time, the default value is Nonedic = dic_pop.pop ('k1 ', 100) # {'k3': 'v3 ', 'k1': 'v4 ', 'k2 ': 'v2'} does not change the original dictionary. You need to define a new dictionary to receive print (dic_pop) # {'k2': 'v2', 'k3 ': 'v3 '} print (dic) # v4

• Popitem (self) pops up an object, because it is unordered, so it is really a pain

Dic_popitem = {'k1 ': 'v1', 'k2': 'v2', 'k3 ': 'v3', 'k1 ': 'v4'} dic_popitem.popitem () #{'k1 ': 'v4', 'k3 ': 'v3'} the deleted object is not necessarily print (dic_popitem)

• Setdefault (self, k, d = None) is similar to get

dic_default = {'k1':'v1','k2':'v2','k3':'v3','k1':'v4'}dic_default_get = dic_get.setdefault('k1','rookieJX')print(dic_default_get) # v4dic_default_get2 = dic_default.get('k','rookieJX')print(dic_default_get2) # rookieJX

• Update (self, E = None, ** F) the dictionary dict2's key/value pairs are updated to dict, which seems to be similar to extend, but no new dictionary is generated.

dic_update = {'k1':'v1','k2':'v2','k3':'v3','k1':'v4'}dic_other = {'k10':'v4'}dic_update.update(dic_other)print(dic_update) # {'k3': 'v3', 'k1': 'v4', 'k2': 'v2', 'k10': 'v4'}

• All values (self) values

dic_values =  {'k1':'v1','k2':'v2','k3':'v3','k1':'v4'}dic_values_values = dic_values.values()print(dic_values_values) # ['v2', 'v4', 'v3']