Davrot at 16:18, 17 October 2025

2025-10-17T16:18:59Z

← Older revision		Revision as of 16:18, 17 October 2025
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	== [https://docs.python.org/3/library/operator.html Behind the curtain] ==		== [https://docs.python.org/3/library/operator.html Behind the curtain] ==
	~~{: .topic-optional}~~ This is an optional topic!		'''This is an optional topic!'''

	If you do a + b, in reality this is internally replaced by add(a, b).		If you do a + b, in reality this is internally replaced by add(a, b).

Davrot: Created page with "Questions to [mailto:davrot@uni-bremen.de David Rotermund] == Number is Python == In Python everything is a class. Numbers are classes as well. === Integer === a_number = 0 print(type(a_number)) # -> == FLOATing point number == a_second_number = 3.33 print(type(a_second_number)) # -> == Conversion (i.e. casts) between types..."

2025-10-15T10:34:40Z

Created page with "Questions to [mailto:davrot@uni-bremen.de David Rotermund] == Number is Python == In Python everything is a class. Numbers are classes as well. === Integer === <syntaxhighlight lang="python">a_number = 0 print(type(a_number)) # -> <class 'int'></syntaxhighlight> == FLOATing point number == <syntaxhighlight lang="python">a_second_number = 3.33 print(type(a_second_number)) # -> <class 'float'></syntaxhighlight> == Conversion (i.e. casts) between types..."

New page

Questions to [mailto:davrot@uni-bremen.de David Rotermund]

== Number is Python ==
In Python everything is a class. Numbers are classes as well.

=== Integer ===
<syntaxhighlight lang="python">a_number = 0
print(type(a_number)) # -> <class 'int'></syntaxhighlight>

== FLOATing point number ==
<syntaxhighlight lang="python">a_second_number = 3.33
print(type(a_second_number)) # -> <class 'float'></syntaxhighlight>

== Conversion (i.e. casts) between types ==
<syntaxhighlight lang="python">a_second_number = 3.33
a_second_number = int(a_second_number)
print(type(a_second_number)) # -> <class 'int'></syntaxhighlight>
{| class="wikitable"
!Examples
|-
|[https://docs.python.org/3/library/functions.html#float float(x=0.0)]
|-
|[https://docs.python.org/3/library/functions.html#bin bin(x)]
|-
|[https://docs.python.org/3/library/functions.html#bool bool(x=False)]
|-
|[https://docs.python.org/3/library/functions.html#func-bytes bytes(source=b’’)]
|-
|[https://docs.python.org/3/library/functions.html#complex complex(real=0, imag=0)]
|-
|[https://docs.python.org/3/library/functions.html#hex hex(x)]
|-
|[https://docs.python.org/3/library/functions.html#int int(x=0)]
|-
|[https://docs.python.org/3/library/functions.html#func-str str(object=’’)]
|}

== [https://docs.python.org/3/library/stdtypes.html#numeric-types-int-float-complex Basic math operations] ==
Order of operations: 1. Parentheses 2. Exponents 3. Multiplication/Division 4. Addition/Subtraction
{| class="wikitable"
!Operator
!Description
|-
|x + y
|sum of x and y
|-
|x - y
|difference of x and y
|-
|x * y
|product of x and y
|-
|x / y
|quotient of x and y
|-
|x // y
|floored quotient of x and y
|-
|x % y
|remainder of x / y
|-
| -x
|x negated
|-
| +x
|x unchanged
|}
{| class="wikitable"
!Operator
!Description
|-
|abs(x)
|absolute value or magnitude of x
|-
|int(x)
|x converted to integer
|-
|float(x)
|x converted to floating point
|-
|complex(re, im)
|a complex number with real part re, imaginary part im. im defaults to zero.
|-
|c.conjugate()
|conjugate of the complex number c
|-
|divmod(x, y)
|the pair (x // y, x % y)
|-
|pow(x, y)
|x to the power y
|-
|x ** y
|x to the power y
|}

== “True division” ==
<syntaxhighlight lang="python">print(5 / 2) # -> 2.5
print(6 / 2) # -> 3.0</syntaxhighlight>

== “Floor division” ==
<syntaxhighlight lang="python">print(5 // 2) # -> 2
print(6 // 2) # -> 3</syntaxhighlight>

== Inplace Operation ==
{| class="wikitable"
!Inplace Operation
!Short for
|-
|a += b
|a = a + b
|-
|a &= b
|a = a & b
|-
|a //= b
|a = a // b
|-
|a <<= b
|a = a << b
|-
|a %= b
|a = a % b
|-
|a *= b
|a = a * b
|-
|a @= b
|a = a @ b
|-
|= b
|b
|-
|a **= b
|a = a ** b
|-
|a >>= b
|a = a >> b
|-
|a -= b
|a = a - b
|-
|a /= b
|a = a / b
|-
|a ^= b
|a = a ^ b
|}

== [https://docs.python.org/3/library/stdtypes.html#boolean-operations-and-or-not Boolean Operations — and, or, not] ==
{| class="wikitable"
!Operation
!Result
|-
|x or y
|if x is false, then y, else x
|-
|x and y
|if x is false, then x, else y
|-
|not x
|if x is false, then True, else False
|}

== [https://docs.python.org/3/library/stdtypes.html#boolean-operations-and-or-not Comparisons] ==
{| class="wikitable"
!Operation
!Meaning
|-
|<
|strictly less than
|-
|<=
|less than or equal
|-
|>
|strictly greater than
|-
|>=
|greater than or equal
|-
|==
|equal
|-
|!=
|not equal
|-
|is
|object identity
|-
|is not
|negated object identity
|}

== [https://docs.python.org/3/library/stdtypes.html?highlight=elif#bitwise-operations-on-integer-types Bitwise Operations on Integer Types] ==
{| class="wikitable"
!Operation
!Result
|-
|y
|bitwise or of x and y
|-
|x ^ y
|bitwise exclusive or of x and y
|-
|x & y
|bitwise and of x and y
|-
|x << n
|x shifted left by n bits
|-
|x >> n
|x shifted right by n bits
|-
|~x
|the bits of x inverted
|}

== [https://docs.python.org/3/library/math.html More math operations (math lib)] ==
You need to include the math lib for that! (Only once per .py file and in the beginning of the file)

However, don’t get used to it. As a data scientist you will not use it. You will use Numpy.<syntaxhighlight lang="python">import math
print(math.cos(math.pi))</syntaxhighlight>

=== Examples ===
{| class="wikitable"
![https://docs.python.org/3/library/math.html#number-theoretic-and-representation-functions Number-theoretic and representation functions]
|-
|math.ceil(x)
|-
|math.comb(n, k)
|-
|math.fabs(x)
|-
|math.factorial(n)
|-
|math.floor(x)
|-
|math.fmod(x, y)
|-
|math.fsum(iterable)
|-
|math.isclose(a, b, *, rel_tol=1e-09, abs_tol=0.0)
|-
|math.isfinite(x)
|-
|math.isinf(x)
|-
|math.isnan(x)
|-
|math.perm(n, k=None)
|-
|math.prod(iterable, *, start=1)
|-
|math.trunc(x)
|}
{| class="wikitable"
![https://docs.python.org/3/library/math.html#constants Constants]
|-
|math.pi
|-
|math.e
|-
|math.inf
|-
|math.nan
|}
{| class="wikitable"
![https://docs.python.org/3/library/math.html#power-and-logarithmic-functions Power and logarithmic functions]
|-
|math.cbrt(x)
|-
|math.exp(x)
|-
|math.exp2(x)
|-
|math.expm1(x)
|-
|math.log(x[,base])
|-
|math.log1p(x)
|-
|math.log2(x)
|-
|math.log10(x)
|-
|math.pow(x, y)
|-
|math.sqrt(x)
|}
{| class="wikitable"
![https://docs.python.org/3/library/math.html#trigonometric-functions Trigonometric functions]
|-
|math.acos(x)
|-
|math.asin(x)
|-
|math.atan(x)
|-
|math.atan2(y, x)
|-
|math.cos(x)
|-
|math.sin(x)
|-
|math.tan(x)
|-
|math.dist(p, q)
|}
{| class="wikitable"
![https://docs.python.org/3/library/math.html#angular-conversion Angular conversion]
|-
|math.degrees(x)
|-
|math.radians(x)
|}
{| class="wikitable"
![https://docs.python.org/3/library/math.html#hyperbolic-functions Hyperbolic functions]
|-
|math.acosh(x)
|-
|math.asinh(x)
|-
|math.atanh(x)
|-
|math.cosh(x)
|-
|math.sinh(x)
|-
|math.tanh(x)
|}

== [https://docs.python.org/3/library/operator.html Behind the curtain] ==
{: .topic-optional} This is an optional topic!

If you do a + b, in reality this is internally replaced by add(a, b).

These are the [https://docs.python.org/3/library/operator.html#mapping-operators-to-functions “Mapping Operators to Functions”]:
{| class="wikitable"
!Operation
!Syntax
!Function
|-
|Addition
|a + b
|add(a, b)
|-
|Concatenation
|seq1 + seq2
|concat(seq1, seq2)
|-
|Containment Test
|obj in seq
|contains(seq, obj)
|-
|Division
|a / b
|truediv(a, b)
|-
|Division
|a // b
|floordiv(a, b)
|-
|Bitwise And
|a & b
|and_(a, b)
|-
|Bitwise Exclusive Or
|a ^ b
|xor(a, b)
|-
|Bitwise Inversion
|~ a
|invert(a)
|-
|Bitwise Or
|b
|or_(a, b)
|-
|Exponentiation
|a ** b
|pow(a, b)
|-
|Identity
|a is b
|is_(a, b)
|-
|Identity
|a is not b
|is_not(a, b)
|-
|Indexed Assignment
|obj[k] = v
|setitem(obj, k, v)
|-
|Indexed Deletion
|del obj[k]
|delitem(obj, k)
|-
|Indexing
|obj[k]
|getitem(obj, k)
|-
|Left Shift
|a << b
|lshift(a, b)
|-
|Modulo
|a % b
|mod(a, b)
|-
|Multiplication
|a * b
|mul(a, b)
|-
|Matrix Multiplication
|a @ b
|matmul(a, b)
|-
|Negation (Arithmetic)
| - a
|neg(a)
|-
|Negation (Logical)
|not a
|not_(a)
|-
|Positive
| + a
|pos(a)
|-
|Right Shift
|a >> b
|rshift(a, b)
|-
|Slice Assignment
|seq[i:j] = values
|setitem(seq, slice(i, j), values)
|-
|Slice Deletion
|del seq[i:j]
|delitem(seq, slice(i, j))
|-
|Slicing
|seq[i:j]
|getitem(seq, slice(i, j))
|-
|String Formatting
|s % obj
|mod(s, obj)
|-
|Subtraction
|a - b
|sub(a, b)
|-
|Truth Test
|obj
|truth(obj)
|-
|Ordering
|a < b
|lt(a, b)
|-
|Ordering
|a <= b
|le(a, b)
|-
|Equality
|a == b
|eq(a, b)
|-
|Difference
|a != b
|ne(a, b)
|-
|Ordering
|a >= b
|ge(a, b)
|-
|Ordering
|a > b
|gt(a, b)
|}
[https://docs.python.org/3/library/operator.html#in-place-operators In-place Operators]
{| class="wikitable"
|a += b
|a = iadd(a, b)
|-
|a &= b
|a = iand(a, b)
|-
|a += b for a and b '''sequences'''
|a = iconcat(a, b)
|-
|a //= b
|a = ifloordiv(a, b)
|-
|a <<= b
|a = ilshift(a, b)
|-
|a %= b
|a = imod(a, b)
|-
|a *= b
|a = imul(a, b)
|-
|a @= b
|a = imatmul(a, b)
|-
|= b
|a = ior(a, b)
|-
|a **= b
|a = ipow(a, b)
|-
|a >>= b
|a = irshift(a, b)
|-
|a -= b
|a = isub(a, b)
|-
|a /= b
|a = itruediv(a, b)
|-
|a ^= b
|a = ixor(a, b)
|}

Basic Math Operations - Revision history

Davrot at 16:18, 17 October 2025