table of Contents

Abnormal TODO

Universal catch exceptions formula

try:
    # 逻辑代码
    1/0
except Exception as e:
    print(e)

division by zero

Copy depth

copy

Copy / Copy shallow / deep copy of the data types are variable terms for the

l1 = ['a'，'b'，'c'，['d'，'e'，'f']]
l2 = l1

l1.append('g')

print(l1)  # ['a'，'b'，'c'，['d'，'e'，'f']，'g']
print(l2)  # ['a'，'b'，'c'，['d'，'e'，'f']，'g']

If l1 l2 is a copy of the object, any change in the data element type l1 inside, the elements within l2 will also change, since the type of the variable value becomes constant id

Shallow copy

import copy


l1 = ['a'，'b'，'c'，['d'，'e'，'f']]
l2 = copy.copy(l1)

l1.append('g')

print(l1)  # ['a'，'b'，'c'，['d'，'e'，'f']，'g']
print(l2)  # ['a'，'b'，'c'，['d'，'e'，'f']]

l1[3].append('g')

print(l1)  # ['a'，'b'，'c'，['d'，'e'，'f'，'g']，'g']
print(l2)  # ['a'，'b'，'c'，['d'，'e'，'f'，'g']]

If l1 l2 shallow copy of the object, the immutable elements within changed l1, l2 unchanged; if the variable elements in the changed l1, l2 will follow the change

Deep copy

import copy


l1 = ['a'，'b'，'c'，['d'，'e'，'f']]
l2 = copy.deepcopy(l1)

l1.append('g')

print(l1)  # ['a'，'b'，'c'，['d'，'e'，'f']，'g']
print(l2)  # ['a'，'b'，'c'，['d'，'e'，'f']]

l1[3].append('g')

print(l1)  # ['a'，'b'，'c'，['d'，'e'，'f'，'g']，'g']
print(l2)  # ['a'，'b'，'c'，['d'，'e'，'f']]

If l1 l2 is deep copy of the object, the immutable elements within changed l1, l2 unchanged; if the variable elements in the changed l1, l2 will not change, i.e. l1 l2 never change because of change

Built-in data type Method

Built-in digital type method

Integer

Role: Defining age / height / weight / id number
Defined method:

age = 18
age = int('18')

method: + - * / % // **
Value of a plurality of values or: a value
Ordered or disordered: they not say this orderly disorder
Variable or non-variable: immutable

Variable: id value becomes constant, the value becomes variable id

Float

Role: Define wage / price
Defined method:

salary = 3.2

salary = float('3.2')

method:+ - * / % // **
Value of a plurality of values or: a value
Ordered or disordered: they not say this orderly disorder
Variable or non-variable: immutable

String type built-in method

Role: Name /
Defined method:

name = 'nick'
name = "nick"
name = '''
nick
nick
'''
name = """
nick
nick
"""
name = "'nick'"
name = '"nick"'

method
1. Priority grasp
  1. Index values
  2. slice
  3. length
  4. Segmentation split
  5. In addition to the blank strip on both sides
  6. Member operator in & emsp; not in
  7. for loop
2. Need to know
  1. lstrip/rstrip
  2. rsplit
  3. upper/lower
  4. startstwith/endswith
  5. join
  6. replace
  7. isdigit
3. To understanding
  1. find/rfind/index/rindex/count
  2. Center / bright / rjust / zfill
  3. expantabs
  4. capitalize/swapcase/title
  5. series is
Value of a plurality of values or: a value
Ordered or disordered: Ordered
Variable or non-variable: immutable

List type built-in method

Role: Multiple girlfriend /
Is defined by: a plurality of spaced apart elements of any data type comma in []

friends_list = ['longzeluola'，'canglaoshi'，'qiaobenai'，'nick']
lis = list('abcd')

method:
1. Priority grasp
  1. Index value (in turn can take change)
  2. slice
  3. length
  4. append
  5. Member operator
  6. for loop
2. Need to know
  1. count
  2. remove
  3. reverse
  4. pop
  5. insert
  6. sort
  7. index
  8. of the
  9. extend
  10. clear
Value of a plurality of values or: a plurality of values
Ordered or disordered: Ordered
Variable or immutable: variable

Ancestral type built-in method

Role: similar to the list, you can not keep taking
Defined method:

friends_tuple = ('longzeluola'，'canglaoshi'，'qiaobenai'，'nick')
tup = tuple('abcd')

method
1. Priority grasp
  1. Index values (can not be changed)
  2. slice
  3. length
  4. Member operator
  5. for loop
  6. count
  7. index
Value of a plurality of values or: a plurality of values
Ordered or disordered: Ordered
Variable or immutable: immutable variable that says no

A dictionary built-in methods

Role: value too easy to keep a list, use a dictionary to take trouble
Defined method:

nick_info_dict = {
'name':'nick'，
'height':180，
'weight':140，
'hobby_list':['read'，'run'，'music'，'fishing'，'programming'，'coding'，'debugging']
}

for k，v in nick_info_dict.items():
    print(k，v)

method
1. Priority grasp
  1. Key Value
  2. length
  3. keys/values/items
  4. for loop
  5. Member operator
2. Need to know
  1. pop
  2. fromkeys
  3. setdefault
  4. get
  5. update
  6. of the
Value of a plurality of values or: a plurality of values
Ordered or disordered: disordered
Variable or immutable: variable

Set type built-in method

Action: a plurality of stored values to be set between the operation
Defined method:

s = set()

s = {1，2，3，4，5，1}

method:
1. Priority grasp
  1. Deduplication
  2. Union |
  3. Intersection &
  4. Difference set -
  5. Symmetric difference ^
  6. Superset> emsp &;> =
  7. 子集 <&emsp；<=
  8. ==
2. Need to know
  1. add
  2. difference_update
  3. isdisjoint
  4. remove # value error does not exist
  5. discard # without error
Value of a plurality of values or: a plurality of values
Ordered or disordered: disordered
Variable or immutable: variable

Boolean

Role: generally used for determining, in addition to 0 / None / air / False carrying boolean value False, carrying other data types Boolean value is True

Data type classification

By the number of values

A value	Multiple values
Integer / Float / String	List / Ganso / dictionary / collection /

By order-disorder

Ordered	Disorderly
String / list / ancestral	Dictionary / collection

By variable immutable

variable	Immutable
List / dictionary / collection	Integer / Float / String

Advanced Python Summary