Python 3: Operators

By Xah Lee. Date: . Last updated: .

Arithmetic Operators

Arithmetic
purposesyntaxfunction
additiona + badd(a, b)
Subtractiona - bsub(a, b)
Negation- aneg(a)
Multiplicationa * bmul(a, b)
Divisiona / btruediv(a, b)
Divisiona // bfloordiv(a, b)
Moduloa % bmod(a, b)
Exponentiationa ** bpow(a, b)

The “function” column is the function from the “operator” module. You can use it after you import operator. example:

# -*- coding: utf-8 -*-
# Python 3

import operator

print(operator.add(3,4))  # prints 7

10.3. operator — Standard operators as functions — Python v3.3.3 documentation #mapping-operators-to-functions

Assignment Operators

# -*- coding: utf-8 -*-
# Python 3

# add and assign
c = 0
c += 1
print(c)    # 1

# substract and assign
c = 0
c -= 2
print(c)    # -2

# multiply and assign
c = 2
c *= 3
print(c)    # 6

# exponent and assign
c = 3
c **= 2
print(c)    # 9

# divide and assign
c = 7
c /= 2
print(c)    # 3.5

# modulus (remainder) and assign
c = 13
c %= 5
print(c)    # 3

# quotient and assign
c = 13
c //= 5
print(c)    # 2

Note: Python doesn't support ++ or --.

Warning: ++i may not generate any error, but it doesn't do anything.

Bit Operators

Bit Operators
purposesyntaxfunction
anda & band_(a, b)
ora | bor_(a, b)
xora ^ bxor(a, b)
invert~ ainvert(a)
Right Shifta >> brshift(a, b)
Left Shifta << blshift(a, b)
# -*- coding: utf-8 -*-
# Python 3

# 0b101 would mean binary 101
# the "{:2b}" means print in binary, and use 2 slots.

# bitwise And
print( "{:2b}".format(0b11 & 0b10) )   # binary 10


# bitwise Or
print( "{:2b}".format(0b11 | 0b10) )   # binary 11

# xor. true if both sides differ
print( "{:2b}".format(0b00 ^ 0b10) )   # binary 10

# binary invert
print( "{:2b}".format(~ 0b1) )   # binary -10  (odd result!)

Sequence Operators

Sequence Operators
purposesyntaxfunction
get itemobj[k]getitem(obj, k)
assign itemobj[k] = vsetitem(obj, k, v)
delete itemdel obj[k]delitem(obj, k)
joinseq1 + seq2concat(seq1, seq2)
if existobj in seqcontains(seq, obj)
format strings % objmod(s, obj)

Boolean Operators

Boolean Operators
purposesyntaxfunction
to booleanobjtruth(obj)
notnot anot_(a)
equala == beq(a, b)
not equala != bne(a, b)
less thana < blt(a, b)
less equala <= ble(a, b)
greatera > bgt(a, b)
greater equala >= bge(a, b)
same objecta is bis_(a, b)
not same objecta is not bis_not(a, b)

2. Lexical analysis — Python v3.3.3 documentation #operators

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Python 3

Lang Detail

  1. Print Version String
  2. Quoting String
  3. String Operations
  4. Format String
  5. Operators
  6. Object, ID, Type

Misc

  1. Traverse Directory
  2. Sort List, Matrix, Object
  3. Python 3: Map with Side Effect Doesn't Work If Result is Not Used
  4. Python 3 Closure
  5. Python 2 and 3 Difference