There is something wrong with this code, when you run this code, it will say 'NameError: name 'A' is not defined'.

!!!!!!!!!! The parameters in other functions will also need to change!!!!!! In order to fix this, I think you can add a parameter 'last', instead of setting 'last' as default, since that will cause the NameError.

I don't believe the else statement self.root = this_node in the below remove function is correct. If there is no previous node, that means you are at the root; and the root should be set to next not this_node

    def remove (self, d):
        this_node = self.root

        while this_node:
            if this_node.get_data() == d:
                next = this_node.get_next()
                prev = this_node.get_prev()
                
                if next:
                    next.set_prev(prev)
                if prev:
                    prev.set_next(next)
                else:
                    self.root = this_node
                self.size -= 1
                return True		# data removed
            else:
                this_node = this_node.get_next()
        return False  # data not found

Is this the right approach ?

class node:
    def getHeight(self):
        if self is None:
            return -1
        return 1 + max(self.leftChild.getHeight(), self.rightChild.getHeight())

class Tree:
    def getHeight(self):
        if self.root:
            return self.root.getHeight()
        else:
            return -1

In this project, if the user inputs a text with alpabetic characters as the choice variable, it gives an error. Even if the choice is 1 or 2, if the user inputs a alphabetic string, it gives an error as well. So, we need to check the user's answer and respond accordingly, so that it doesn't give an error.

The reason for the error is that the key 'avg_high' can't be found because it has been changed to 'av_hi'.

Here is the link to the file: https://github.com/joeyajames/Python/blob/master/Pandas/pandas_weather.py

Here is the output:

--------------------------------------------------
[ 11. iterate rows of df with a for loop ]

---------------------------------------------------------------------------
TypeError                                 Traceback (most recent call last)
~/opt/anaconda3/lib/python3.7/site-packages/pandas/core/indexes/base.py in get_value(self, series, key)
   4409             try:
-> 4410                 return libindex.get_value_at(s, key)
   4411             except IndexError:

pandas/_libs/index.pyx in pandas._libs.index.get_value_at()

pandas/_libs/index.pyx in pandas._libs.index.get_value_at()

pandas/_libs/util.pxd in pandas._libs.util.get_value_at()

pandas/_libs/util.pxd in pandas._libs.util.validate_indexer()

TypeError: 'str' object cannot be interpreted as an integer

During handling of the above exception, another exception occurred:

KeyError                                  Traceback (most recent call last)
<ipython-input-14-1fc7b7226e62> in <module>
      2 header("11. iterate rows of df with a for loop")
      3 for index, row in df.iterrows():
----> 4     print (index, row["month"], row["avg_high"])

~/opt/anaconda3/lib/python3.7/site-packages/pandas/core/series.py in __getitem__(self, key)
    869         key = com.apply_if_callable(key, self)
    870         try:
--> 871             result = self.index.get_value(self, key)
    872 
    873             if not is_scalar(result):

~/opt/anaconda3/lib/python3.7/site-packages/pandas/core/indexes/base.py in get_value(self, series, key)
   4416                     raise InvalidIndexError(key)
   4417                 else:
-> 4418                     raise e1
   4419             except Exception:
   4420                 raise e1

~/opt/anaconda3/lib/python3.7/site-packages/pandas/core/indexes/base.py in get_value(self, series, key)
   4402         k = self._convert_scalar_indexer(k, kind="getitem")
   4403         try:
-> 4404             return self._engine.get_value(s, k, tz=getattr(series.dtype, "tz", None))
   4405         except KeyError as e1:
   4406             if len(self) > 0 and (self.holds_integer() or self.is_boolean()):

pandas/_libs/index.pyx in pandas._libs.index.IndexEngine.get_value()

pandas/_libs/index.pyx in pandas._libs.index.IndexEngine.get_value()

pandas/_libs/index.pyx in pandas._libs.index.IndexEngine.get_loc()

pandas/_libs/hashtable_class_helper.pxi in pandas._libs.hashtable.PyObjectHashTable.get_item()

pandas/_libs/hashtable_class_helper.pxi in pandas._libs.hashtable.PyObjectHashTable.get_item()

KeyError: 'avg_high'

@joeyajames The code of matplotlib library as well as pandas library is not executing since there is a typo mistake in code . Please assign me this issue .

Thank you very much for your video and code!

But I actually have one question about your codes time complexity. The following two lines of codes showing that you are using Python slicing to construct the left half and right half:

L = A[first:middle+1] R = A[middle+1:last+1]

Since the slicing operator is O(k), my question is does the time complexity of the merge sort still be O(nlogn) if we use the Python list slicing in our codes?

Thank you very much!

There are some mistakes in your read me the file so we make some correction in to it. Hope it will be helpful to you. Just accept our commits and keep coding.

Threshold was used before assigning any value or defining and this cause NameError. So, changed quick_sort2 function and made a PR. Now it take threshold by computing it and code is working perfectly.