3. Python operator

Introduction to the 3-1.python operator

1. Common operators in Python +: Add (can be a number added, or it can bestring addition, the string's + represents the concatenation of the string） -: Means minus orTake counter *: Multiply (can be multiplied by two digits, or it can bethe string is multiplied by a number, which indicates that the string repeats several times） **: A power operation, such as:2**3 represents 2 of the three-time Square） /: Except operation (when either divisor or any of the dividend is a decimal, the result of the Division also retains the decimal） //: Two numbers divided by their integral parts %: Two numbers divide to take the remaining number &: Bitwise AND (Bitwise and is the first to convert two numbers into binary number, and then bitwise AND operation, only two bits are 1 o'clock is 1such as7&18The output is 2 steps to convert the 7 and 18 respectively into 2 binary,00000111And00010010The two are then bitwise and operated on them, i.e.1 and 0 for 0,1 and 1 for 1,0 and 1 for 0It gets 00000010, which is the decimal number, which is 2.attached: Bring up the computer's own calculator, click "View" in the status bar, and then select "Programmer mode" can be directly used to calculate the number of various binary; |: Bitwise OR (A bitwise OR representation of one of them is 1, which results in 1, only 0 for both 0 o'clock） ^: Bitwise XOR OR (different or not the same, get 1, that is, 0 and 0 are 1，the same is achieved by 0, i.e. 0 and 0,1 and 1 are 0） not: Logical Non- and: Logic and or: Logical OR ~: Rollover by bit (the resulting result has aCalculation formula: ~x=-(x+1)) >>: Move right (i.e.Moves a number corresponding to the binary number to the right, the missing bit complement after moving out 0） <<: Shift Left (rule:Shift left N unitsThe resulting result in decimal is actually equal to the original number multiplied by2 of the n-th square, such as 2<<3 equals 2*2 three times, the result is 16) 2. Precedence of operators:Priority ranking is as follows:First: function invocation, addressing, subscriptSecond: Power operation * *Third: rollover operation ~Fourth: plus signFifth: *,/,%Sixth: +,-Seventh: Shift OperationEighth: Bitwise and &, bitwise OR |, bitwise XOR ^nineth: comparison operator >,<,==Tenth: not, and, or 3. Priority RuleIn general, it is left-associative, and when the assignment occurs, it is usually right-associative;

Introduction to 3-2.python expressions

Python expression differs from print execution result: the expression output preserves single quotes when it is a string, and the print output does not have single quotes

3. Python operator