Using the AND and NOT Operator in Python

Question

Here is my custom class that I have that represents a triangle   I m trying to write code that checks to see if self a  self b  and self c are greater than 0  which would mean that I have Angle  Angle  Angle     Below you will see the code that checks for A and B  however when I use just self a    0 then it works fine   I believe I m not using  amp  correctly   Any ideas   Here is how I am calling it  print myTri detType    class Triangle         Angle A To Angle C Connects Side F       Angle C to Angle B Connects Side D       Angle B to Angle A Connects Side E      def   init   self  a  b  c  d  e  f           self a   a         self b   b         self c   c         self d   d         self e   e         self f   f      def detType self            Triangle Type AAA         if self a    0  amp  self b    0              return self a           If self a  gt  10               return AAA           Triangle Type AAS           elif self a   0               return AAS           Triangle Type ASA           Triangle Type SAS           Triangle Type SSS             else               return unknown

User · Answer

It s called and and or in Python

User · Answer

Use the keyword and  not  amp  because  amp  is a bit operator   Be careful with this    just so you know  in Java and C    the  amp  operator is ALSO a bit operator  The correct way to do a boolean comparison in those languages is  amp  amp   Similarly   is a bit operator  and    is a boolean operator  In Python and and or are used for boolean comparisons

User · Answer

You should write    if  self a    0  and  self b    0        amp   is the bit wise operator and does not suit for boolean operations  The equivalent of    amp  amp   is  and  in Python   A shorter way to check what you want is to use the  in  operator    if 0 not in  self a  self b      You can check if anything is part of a an iterable with  in   it works for     Tuples  I E    foo  in   foo   1  c  etc  will return true Lists  I E    foo  in   foo   1  c  etc  will return true Strings  I E    a  in  ago  will return true Dict  I E    foo  in   foo     bar   will return true   As an answer to the comments    Yes  using  in  is slower since you are creating an Tuple object  but really performances are not an issue here  plus readability matters a lot in Python   For the triangle check  it s easier to read    0 not in  self a  self b  self c    Than    self a    0  and  self b    0  and  self c    0     It s easier to refactor too   Of course  in this example  it really is not that important  it s very simple snippet  But this style leads to a Pythonic code  which leads to a happier programmer  and losing weight  improving sex life  etc   on big programs

[python] Using the AND and NOT Operator in Python

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