Computer Science
Membership Operator in Python
The membership operator in Python is used to check if a value exists in a sequence or not. It returns a Boolean value of True or False depending on whether the value is present or not. The two membership operators are "in" and "not in".
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eBook - ePubAn Introduction to Python Programming: A Practical Approach
step-by-step approach to Python programming with machine learning fundamental and theoretical principles.
- Dr. Krishna Kumar Mohbey; Dr. Brijesh Bakariya(Author)
- 2021(Publication Date)
- BPB Publications(Publisher)
A membership operator is used to test if a sequence is presented in an object. Here, an object may be strings, lists, or tuples. There are two types of membership operators in and not. Let us take an example of using these operators.- Operator (in) : This operator evaluates to true if it finds a variable in the specified sequence and false otherwise.
- Operator (not) : This operator evaluates to true if it does not find a variable in the specified sequence and false otherwise.
Identity operators
This operator is used to compare the objects, not if they are equal, but if they are the same object, with the exact memory location. There are two types of identity operators is and is not
eBook - ePubPython Internals for Developers
Practice Python 3.x Fundamentals, Including Data Structures, Asymptotic Analysis, and Data Types
- Sonam Chawla Bhatia(Author)
- 2021(Publication Date)
- BPB Publications(Publisher)
Table 1.7 describes the various Python membership operators:Operator Description in Outputs True if left operand is part of right operand. not in Outputs True if left operand is not part of right operand. Table 1.7: Python membership operatorsExample 1.9: Membership operators- ’e’ in ‘hello’//Output True
- ‘z’ in ‘hello’//Output False
- ‘z’ not in ‘hello’//Output True
- ‘e’ not in ‘hello’//Output False
Bitwise operators
Bitwise operators operate on each bit of number. Bitwise operator converts operands to a binary number, performs operations on each bit, converts the binary output to a decimal number, and outputs decimal number. Table 1.8 describes the various Python membership operators:Operator Name Description & Bitwise AND It is a binary operator. It compares bits of both the binary numbers and sets the output bit to 1 if both the bits are 1. | Bitwise OR It is a binary operator. It compares bits of both the binary numbers and sets the output bit to 1 if any of the bit is 1. ^ Bitwise XOR It is a binary operator. It compares bits of both the binary numbers and sets the output bit to 1 if any one bit is 1. If both the bits are 0 or 1, then it sets the output bit to 0. ~ Bitwise NOT It is a unary operator. It sets the output bit to 0 if the input bit is 1 and vice versa. << Left Shift It is a binary operator. The left operand is the number to be shifted and the right operand is the number of bits to be shifted. Shifts all bits to the left by the number of positions as mentioned in the right operand. Fills the rightmost bits by 0.>> Right Shift It is a binary operator. The left operand is the number to be shifted and the right operand is the number of bits to be shifted. It shifts all bits to the right by the number of positions as mentioned in the right operand and removes the rightmost bit. It fills the leftmost bits by 0.
eBook - PDF- Ted Herman(Author)
- 2013(Publication Date)
- Chapman and Hall/CRC(Publisher)
The membership operation is also valid for sets and dictionaries. For dictionaries, the operation returns True if the left argument is a key in the dictionary. False in {1:'a',False:0} ➜ True 0 in {1:'a',False:0} ➜ False Finally, there is a Python operator doing the opposite of in (no, it is not called out ): 7 not in [1,2,3,4] ➜ True You can use not in anywhere you would use in to test nonmembership of the left argument in the sequence or dictionary on the right. Hidden Operators: Function Application, Indexing, Lookup Two other operators are unusual because there is no single character or string of characters to represent them. At first sight, these might not even appear to be operators. One has already been introduced, though not as an operator: function application . Temporarily, let “ o ” be a visible symbol for function application. The expression of applying the length function with a string argument could be len o painting ➜ 8 The o operator takes a function name as the left argument and something else, a parameter , that the function uses to find an answer. In fact, Python does not have a symbol o for function application; instead, the notation is: len(painting) ➜ 8 Because there is no special symbol, function application is an implicit operator (also, it is a binary operator). Later, there will be examples where the right argument to function application looks like a tuple, with multiple items separated by commas. The other implicit operator is called indexing . The left argument is a sequence and the right argument is an integer, for instance 'oranges' K 3 ➜ 'n' 48 A Functional Start to Computing with Python where “ K ” represents the indexing operator. The right argument, called the index , identifies which item of the sequence should be returned, counting left to right, starting from zero. Above, the index for 'o' is 0, for 'r' it is 1, and so on. Of course, Python does not use a “ K ” symbol: indexing is an implicit operator.
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