lange

Lazy lists (i.e. Haskell-like ranges) for Python. Latest release | Current code | API documentation

Installation

from package

# Set up a virtualenv. 
python3 -m venv venv
source venv/bin/activate

# Install from PyPI
pip install lange

from source

cd my-project
git clone https://github.com/davips/lange ../lange
pip install -e ../lange

Features

• Stable floating-point range generation, e.g.: 0.8 - 0.6 == 0.2 up to 28 digits (customizable).
• Infinite [1 2 ...] or bounded.
• O(1) access/evaluation lst[3443]

Examples

Arithmetic Progression

# Bounded
from lange import ap

print(ap[0.4, 0.8, ..., 2])
"""
[0.4 0.8 .+. 2.0]
"""

# Infinite + slicing
prog = ap[0.4, 0.8, ...]
print(prog[:5])
"""
[0.4 0.8 .+. 2.0]
"""

# As list
print(list(prog[:5]))
"""
[0.4, 0.8, 1.2, 1.6, 2.0]
"""

print(prog[:5].l)
"""
[0.4, 0.8, 1.2, 1.6, 2.0]
"""

# Towards negative.
print(ap[1, -2, ..., -8].l)
"""
[1, -2, -5, -8]
"""

Geometric Progression

# Bounded
from lange import gp
print(gp[0.4, 0.8, ..., 2])
"""
[0.4 0.8 1.6]
"""

# Infinite + slicing
prog = gp[0.4, 0.8, ...]
print(prog[:5])
"""
[0.4 0.8 .*. 6.4]
"""

# As list
print(list(prog[:5]))
"""
[0.4, 0.8, 1.6, 3.2, 6.4]
"""

print(prog[:5].l)
"""
[0.4, 0.8, 1.6, 3.2, 6.4]
"""

# Using negative step.
print(gp[1, -2, ..., 130].l)
"""
[1, -2, 4, -8, 16, -32, 64, -128]
"""

Other projects

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