8000 Big changes in Numbers, Inline, Closure · gto76/python-cheatsheet@79fca70 · GitHub
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Big changes in Numbers, Inline, Closure
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‎README.md

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@@ -493,11 +493,11 @@ Format
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Numbers
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-------
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```python
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<int> = int(<float/str/bool>) # Or: math.trunc(<float>)
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<float> = float(<int/str/bool>) # Or: <int/float>e±<int>
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<complex> = complex(real=0, imag=0) # Or: <int/float> ± <int/float>j
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<Fraction> = fractions.Fraction(0, 1) # Or: Fraction(numerator=0, denominator=1)
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<Decimal> = decimal.Decimal(<str/int>) # Or: Decimal((sign, digits, exponent))
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<int> = int(<float/str/bool>) # Whole number of any size. Truncates floats.
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<float> = float(<int/str/bool>) # 64-bit decimal number. Also <float>e±<int>.
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<complex> = complex(real=0, imag=0) # Complex number. Also `<float> ± <float>j`.
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<Fraction> = fractions.Fraction(<int>, <int>) # E.g. `Fraction(1, 2) / 3 == Fraction(1, 6)`.
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<Decimal> = decimal.Decimal(<str/int/tuple>) # E.g. `Decimal((1, (2, 3), 4)) == -230_000`.
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```
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* **`'int(<str>)'` and `'float(<str>)'` raise ValueError on malformed strings.**
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* **Decimal numbers are stored exactly, unlike most floats where `'1.1 + 2.2 != 3.3'`.**
@@ -507,54 +507,55 @@ Numbers
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### Built-in Functions
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```python
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<num> = pow(<num>, <num>) # Or: <number> ** <number>
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<num> = abs(<num>) # <float> = abs(<complex>)
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<num> = round(<num> [, ±ndigits]) # Also math.floor/ceil(<number>).
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<num> = min(<collection>) # Also max(<num>, <num> [, ...]).
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<num> = sum(<collection>) # Also math.prod(<collection>).
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<num> = pow(<num>, <num>) # E.g. `pow(2, 3) == 2 ** 3 == 8`.
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<num> = abs(<num>) # E.g. `abs(complex(3, 4)) == 5`.
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<num> = round(<num> [, ±ndigits]) # E.g. `round(123, -1) == 120`.
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<num> = min(<collection>) # Also max(<num>, <num> [, ...]).
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<num> = sum(<collection>) # Also math.prod(<collection>).
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```
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### Math
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```python
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from math import pi, inf, nan, isnan # `inf*0` and `nan+1` return nan.
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from math import sqrt, factorial # `sqrt(-1)` raises ValueError.
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from math import sin, cos, tan # Also: asin, degrees, radians.
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from math import log, log10, log2 # Log accepts base as second arg.
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from math import floor, ceil, trunc # They convert floats into integers.
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from math import pi, inf, nan, isnan # `inf * 0` and `nan + 1` return nan.
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from math import sqrt, factorial # `sqrt(-1)` will raise ValueError.
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from math import sin, cos, tan # Also: asin, acos, degrees, radians.
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from math import log, log10, log2 # Log accepts base as second argument.
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```
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### Statistics
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```python
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from statistics import mean, median, mode # Also: variance, stdev, quantiles.
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from statistics import mean, median, mode # Mode returns the most common item.
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from statistics import variance, stdev # Also: pvariance, pstdev, quantiles.
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```
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### Random
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```python
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from random import random, randint, uniform # Also: gauss, choice, shuffle, seed.
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from random import random, randint, uniform # Also: gauss, choice, shuffle, seed.
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```
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```python
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<float> = random() # Returns a float inside [0, 1).
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<num> = randint/uniform(a, b) # Returns an int/float inside [a, b].
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<float> = gauss(mean, stdev) # Also triangular(low, high, mode).
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<el> = choice(<sequence>) # Keeps it intact. Also sample(pop, k).
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shuffle(<list>) # Shuffles the list in place.
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<float> = random() # Returns a float inside [0, 1).
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<num> = randint/uniform(a, b) # Returns an int/float inside [a, b].
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<float> = gauss(mean, stdev) # Also triangular(low, high, mode).
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<el> = choice(<sequence>) # Keeps it intact. Also sample(p, n).
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shuffle(<list>) # Works on any mutable sequence.
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```
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### Hexadecimal Numbers
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```python
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<int> = ±0x<hex> # Or: ±0b<bin>
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<int> = int('±<hex>', 16) # Or: int('±<bin>', 2)
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<int> = int('±0x<hex>', 0) # Or: int('±0b<bin>', 0)
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<str> = hex(<int>) # Returns '[-]0x<hex>'. Also bin().
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<int> = 0x<hex> # E.g. `0xFF == 255`. Also 0b<bin>.
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<int> = int('±<hex>', 16) # Also int('±0x<hex>/±0b<bin>', 0).
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<str> = hex(<int>) # Returns '[-]0x<hex>'. Also bin().
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```
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### Bitwise Operators
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```python
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<int> = <int> & <int> # And (0b1100 & 0b1010 == 0b1000).
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<int> = <int> | <int> # Or (0b1100 | 0b1010 == 0b1110).
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<int> = <int> ^ <int> # Xor (0b1100 ^ 0b1010 == 0b0110).
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<int> = <int> << n_bits # Left shift. Use >> for right.
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<int> = ~<int> # Not. Also -<int> - 1.
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<int> = <int> & <int> # E.g. `0b1100 & 0b1010 == 0b1000`.
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<int> = <int> | <int> # E.g. `0b1100 | 0b1010 == 0b1110`.
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<int> = <int> ^ <int> # E.g. `0b1100 ^ 0b1010 == 0b0110`.
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<int> = <int> << n_bits # Left shift. Use >> for right.
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<int> = ~<int> # Not. Same as `-<int> - 1`.
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```
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@@ -747,10 +748,10 @@ Inline
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### Comprehensions
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```python
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<list> = [i+1 for i in range(10)] # Or: [1, 2, ..., 10]
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<iter> = (i for i in range(10) if i > 5) # Or: iter([6, 7, 8, 9])
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<set> = {i+5 for i in range(10)} # Or: {5, 6, ..., 14}
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<dict> = {i: i*2 for i in range(10)} # Or: {0: 0, 1: 2, ..., 9: 18}
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<list> = [i+1 for i in range(10)] # Returns `[1, 2, ..., 10]`.
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<iter> = (i for i in range(10) if i > 5) # Returns `iter([6, 7, 8, 9])`.
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<set> = {i+5 for i in range(10)} # Returns `{5, 6, ..., 14}`.
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<dict> = {i: i*2 for i in range(10)} # Returns `{0: 0, 1: 2, ..., 9: 18}`.
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```
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```python
@@ -764,9 +765,9 @@ from functools import reduce
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```
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```python
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<iter> = map(lambda x: x + 1, range(10)) # Or: iter([1, 2, ..., 10])
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<iter> = filter(lambda x: x > 5, range(10)) # Or: iter([6, 7, 8, 9])
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<obj> = reduce(lambda out, x: out + x, range(10)) # Or: 45
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<iter> = map(lambda x: x + 1, range(10)) # Returns `iter([1, 2, ..., 10])`.
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<iter> = filter(lambda x: x > 5, range(10)) # Returns `iter([6, 7, 8, 9])`.
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<obj> = reduce(lambda out, x: out + x, range(10)) # Returns `45`.
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```
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### Any, All
@@ -860,8 +861,7 @@ from functools import partial
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>>> multiply_by_3(10)
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30
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```
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* **Partial is also useful in cases when a function needs to be passed as an argument because it enables us to set its arguments beforehand.**
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* **A few examples being: `'defaultdict(<func>)'`, `'iter(<func>, to_exc)'` and dataclass's `'field(default_factory=<func>)'`.**
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* **Partial is also useful in cases when a function needs to be passed as an argument because it enables us to set its arguments beforehand (`'collections.defaultdict(<func>)'`, `'iter(<func>, to_exc)'` and `'dataclasses.field(default_factory=<func>)'`).**
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### Non-Local
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**If variable is being assigned to anywhere in the scope, it is regarded as a local variable, unless it is declared as a 'global' or a 'nonlocal'.**

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