The Get function in Python

Get () function action

Take Classcount.get (voteilabel,0) as an example:
Classcount.get (voteilabel,0) Returns the value of the Voteilabel element in the dictionary ClassCount and, if none, initializes

• If there is no Voteilabel, the Voteilabel element is generated in the dictionary ClassCount and the corresponding number is 0, which is
  ClassCount = {voteilabel:0}
  At this point the Classcount.get (voteilabel,0) function is to detect and generate new elements, 0 of the parentheses are used as initialization, and then no effect

• When there is a Voteilabel element in the dictionary, the Classcount.get (voteilabel,0) function returns the value corresponding to that element, which is 0

Take the code in the book as an example:
Classcount[voteilabel] = Classcount.get (voteilabel,0) + 1;

• When initializing ClassCount = {}, enter ClassCount at this time, and the output is:
  

  ClassCount = {}

• When you first encounter a new label, add a new label to the dictionary ClassCount and initialize its corresponding value to 0
  Then +1, that is, the label has appeared once, at this time input classcount, the output is:

  ClassCount = {Voteilabel:1}

• When the same label is encountered the second time, Classcount.get (voteilabel,0) returns the corresponding value (the 0 in parentheses does not work, because it has already been initialized), and then +1, when you enter ClassCount, the output is:

  ClassCount = {Voteilabel:2}

As you can see, +1 is a function every time, because it is necessary to record this element regardless of the existence or absence of the dictionary.

The Get function in Python