Comparing lambda closure capturing in Python and javascript

python_lambda_closure.py

# sorry, python doesn't have a built-in table printer
from tabulate import tabulate

max = 3

def get_functions():
  lst = []
  for i in range(0, max):
    lst.append(lambda: i)
  return lst

def get_functions_yield():
  for i in range(0, max):
    yield lambda: i

def get_functions_yield_separate_var():
  for i in range(0, max):
    x = i
    yield lambda: x

def get_functions_yield_separate_context():
  for i in range(0, max):
    yield (lambda x: lambda: x)(i)

def for_f(iterator): 
  for f in iterator():
    yield f()

def for_f_preload(iterator): 
  for f in list(iterator()):
    yield f()


# functions:
functions = [
  get_functions,
  get_functions_yield,
  get_functions_yield_separate_var,
  get_functions_yield_separate_context,
]

# iterations
iterations = [
  for_f,
  for_f_preload
]

headers = ["(index)"]
rows = []

for f in functions:
  headers.append(f.__name__)

for i in iterations:
  row = []
  rows.append(row)
  row.append(i.__name__)

  for f in functions:
    row.append(list(i(f)))

print(tabulate(rows, headers=headers, tablefmt="grid"))

Prints

+---------------+-----------------+-----------------------+------------------------------------+----------------------------------------+
| (index)       | get_functions   | get_functions_yield   | get_functions_yield_separate_var   | get_functions_yield_separate_context   |
+===============+=================+=======================+====================================+========================================+
| for_f         | [2, 2, 2]       | [0, 1, 2]             | [0, 1, 2]                          | [0, 1, 2]                              |
+---------------+-----------------+-----------------------+------------------------------------+----------------------------------------+
| for_f_preload | [2, 2, 2]       | [2, 2, 2]             | [2, 2, 2]                          | [0, 1, 2]                              |
+---------------+-----------------+-----------------------+------------------------------------+----------------------------------------+