# Day04

## 

1. 

   : \[start, stop\[, step\]\]

2. 
3.  \(\)

   ```python
   num1, num2 = [1, 2]
   # (num1, num2) 1, 2
   num3, *num4 = [1,2,3,4,5]
   # (num3, num4)  1, [2,3,4,5] 
   *num5, num6 = [1,2,3,4,5]
   # (num5, num6) [1,2,3,4], 5
   ```

4. 

   `dir(list)`: 

   * 

     |  |  |
     | :---: | :---: |
     | **append** |  |
     | extend | \(\), \(\) |
     | **insert** |  |

     ```text
     # append()
       >>> a = [1,2,3,4]
       >>> a.append(1)
       >>> a
       [1, 2, 3, 4, 1]
     # extend()
       >>> a.extend("5")
       >>> a
       [1, 2, 3, 4, 1, '5']
     # insert()
       >>> a
       [1, 2, 3, 4, 1, '5']
       >>> a.insert(2, 8)
       >>> a
       [1, 2, 8, 3, 4, 1, '5']
     ```

   * 

     |  |  |
     | :---: | :---: |
     | **pop** |  \(\) |
     | **remove** |  |
     | del | \(\),del  python  |
     | clear |  |

     ```text
       # pop()
       >>> a.pop()
       '5'
       >>> a
       [1, 2, 8, 3, 4, 1]
       # remove()
       >>> a.remove(8)
       >>> a
       [1, 2, 3, 4, 1]
       # del
       >>> del a
       >>> a
       Traceback (most recent call last):
         File "", line 1, in 
       NameError: name 'a' is not defined
       # clear()
       >>> a = [1, 2, 3, 4, 1]
       >>> a.clear()
       >>> a
       []
     ```

   * 

     |  |  |
     | :---: | :---: |
     | reverse |  |
     | sort\(self, axis=-1, kind=None, order=None\[, reverse=True\]\) |  ASCII , list.sort\(\) , reverse=True |
     | sorted\(list\) | , \(Python \) |

     ```text
       # reverse()
       >>> a = [1, 2, 3, 4, 1]
       >>> a.reverse()
       >>> a
       [1, 4, 3, 2, 1]
       # sort()
       >>> a.sort()
       >>> a
       [1, 1, 2, 3, 4]
       # sorted()
       >>> a
       [1, 1, 2, 3, 4]
       >>> sorted(a, reverse=True)
       [4, 3, 2, 1, 1]
       >>> a
       [1, 1, 2, 3, 4]
     ```

   * 

     |  |  |
     | :---: | :---: |
     | count |  |
     | index\(data\[, start, end\]\) |  \(\)  |
     | len\(list\) | Python \(\) |

     ```text
       # count()
       >>> a
       [1, 1, 2, 3, 4]
       >>> a.count(1)
       2
       # index()
       >>> a.index(2)
       2
       # len()
       >>> len(a)
       5
     ```

5. 
   * python ****
     * ****: 
     * ****: 
   * : ****
   * : list.copy\(\)  \(\) \(\)
   * ****: 
     * import copy
     * list.deepcopy\(\) \(\)
6.  \(\)
   *  = \[ for  in \] \(\)
   *  = \[ for  in  if \] \(\)
   * :  for  if