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Python

Functional Python (package "fn" by A. Kachayev)

# available in standard Python

from functools import partial

# partial application

plus2 = partial(lambda x, y: x + y, 2)
print plus2(3)

# closures

def makeAdder(i):
    return (lambda n: i + n) # the lambda function is the closure
# end def makeAdder

fs = [makeAdder(i) for i in range(10)]
print [f(4) for f in fs]

def f():
    d = {'y' : 0}
    def g(): # this is the closure
        d['y'] += 1
        return d['y'] # "x" is a (used) free variable, therefore it is captured in the closure
    # end def g
    return g
# end def f

g = f()
print g.__closure__[0].cell_contents
print g()
print g.__closure__[0].cell_contents
print g()

# in Kachayev's fn package

from fn import _
from fn.op import zipwith
from itertools import repeat

# functions (be careful: in the interactive shell "_" means "last output"!)

print list(map(_ * 2, range(5)))
print list(filter(_ < 10, [9,10,11]))
print list(zipwith(_ + _)([0,1,2], repeat(10)))

print _ + _ * _

# streams

from fn import Stream

s = Stream() << [1,2,3,4,5]
print list(s)
print s[1]
print list(s[0:2])

s = Stream() << range(6) << [6,7]
print list(s)

def gen():
    yield 1
    yield 2
    yield 3
#end def gen

s = Stream() << gen << (4,5)
print list(s)

# lazy lists

from fn.iters import take, drop, map
from operator import add

f = Stream()
fib = f << [0, 1] << map(add, f, drop(1, f))

print list(take(10, fib))
print fib[20]
print list(fib[30:35])

# optimized tail recursion

from fn import recur

@recur.tco
def even(x):
    if x == 0: return False, True # i.e False => exit, True => return value
    return odd, (x-1,)# if it was True => call the same function, otherwise call another function
# end def even

@recur.tco
def odd(x):
    if x == 0: return False, False
    return even, (x-1,)
# end def odd

# usually it would fail!
print even(100000)

# partial application

from fn import F, _
from operator import mul

# F(f, *args) is the partial application
# like "functools.partial" but returns "fn.F"

print F(add, 1)(10)

# F << F means function composition, therefore (F(f) << g)(x) == f(g(x))
f = F(add, 1) << F(mul, 100)
print list(map(f, [0, 1, 2]))
print list(map(F() << str << (_ ** 2) << (_ + 1), range(3)))

# pipes

from fn.iters import filter, range

func = F() >> (filter, _ < 6) >> sum
print func(range(10))

# folding

from fn import op

folder = op.foldr(_ * _, 1)
print op.foldl(_ + _)([1, 2, 3])
print folder([1, 2, 3])

from fn import iters

print list(iters.accumulate([1,2,3], add))
print list(iters.flatten([[1,2], [3,4]]))
print list(iters.take(10, fib))
#print list(iters.consume(iter(iters.range(10))), 5) ???
pn = iters.padnone([10,11])
print list(iters.take(10, pn))

nc = iters.ncycles([10,11], 3)
print list(iters.take(10, nc))

rf = iters.repeatfunc(lambda: "test", 3)
print list(iters.take(3, rf))

print list(iters.grouper(3, "ABCDEFG"))

print list(iters.roundrobin('ABC', 'D', 'EF'))

(a, b) = iters.partition(lambda x: x % 2 == 1, iters.range(5))
print list(a), list(b)

(a, b) = iters.splitat(2, iters.range(5))
print list(a), list(b)

(a, b) = iters.splitby(lambda x: x % 2 == 0, iters.range(5))
print list(a), list(b)

print list(iters.powerset([1, 2]))
print list(iters.pairwise(range(4)))

# and other similar nice stuff (see https://pypi.python.org/pypi/fn)
https://snipt.net/embed/d03ba9ed8e3876215f1666d5c9a5032f/
/raw/d03ba9ed8e3876215f1666d5c9a5032f/
d03ba9ed8e3876215f1666d5c9a5032f
python
Python
162
2019-07-16T10:00:41
True
False
False
Jul 24, 2013 at 10:13 AM
/api/public/snipt/69342/
functional-python-package-fn-by-a-kachayev
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href="#L-161">161</a></pre></div></td><td class="code"><div class="highlight"><pre><span></span><span id="L-1"><a name="L-1"></a><span class="c1"># available in standard Python</span> </span><span id="L-2"><a name="L-2"></a> </span><span id="L-3"><a name="L-3"></a><span class="kn">from</span> <span class="nn">functools</span> <span class="kn">import</span> <span class="n">partial</span> </span><span id="L-4"><a name="L-4"></a> </span><span id="L-5"><a name="L-5"></a><span class="c1"># partial application</span> </span><span id="L-6"><a name="L-6"></a> </span><span id="L-7"><a name="L-7"></a><span class="n">plus2</span> <span class="o">=</span> <span class="n">partial</span><span class="p">(</span><span class="k">lambda</span> <span class="n">x</span><span class="p">,</span> <span class="n">y</span><span class="p">:</span> <span class="n">x</span> <span class="o">+</span> <span class="n">y</span><span class="p">,</span> <span class="mi">2</span><span class="p">)</span> </span><span id="L-8"><a name="L-8"></a><span class="k">print</span> <span class="n">plus2</span><span class="p">(</span><span class="mi">3</span><span class="p">)</span> </span><span id="L-9"><a name="L-9"></a> </span><span id="L-10"><a name="L-10"></a><span class="c1"># closures</span> </span><span id="L-11"><a name="L-11"></a> </span><span id="L-12"><a name="L-12"></a><span class="k">def</span> <span class="nf">makeAdder</span><span class="p">(</span><span class="n">i</span><span class="p">):</span> </span><span id="L-13"><a name="L-13"></a> <span class="k">return</span> <span class="p">(</span><span class="k">lambda</span> <span class="n">n</span><span class="p">:</span> <span class="n">i</span> <span class="o">+</span> <span class="n">n</span><span class="p">)</span> <span class="c1"># the lambda function is the closure</span> </span><span id="L-14"><a name="L-14"></a><span class="c1"># end def makeAdder</span> </span><span id="L-15"><a name="L-15"></a> </span><span id="L-16"><a name="L-16"></a><span class="n">fs</span> <span class="o">=</span> <span class="p">[</span><span class="n">makeAdder</span><span class="p">(</span><span class="n">i</span><span class="p">)</span> <span class="k">for</span> <span class="n">i</span> <span class="ow">in</span> <span class="nb">range</span><span class="p">(</span><span class="mi">10</span><span class="p">)]</span> </span><span id="L-17"><a name="L-17"></a><span class="k">print</span> <span class="p">[</span><span class="n">f</span><span class="p">(</span><span class="mi">4</span><span class="p">)</span> <span class="k">for</span> <span class="n">f</span> <span class="ow">in</span> <span class="n">fs</span><span class="p">]</span> </span><span id="L-18"><a name="L-18"></a> </span><span id="L-19"><a name="L-19"></a><span class="k">def</span> <span class="nf">f</span><span class="p">():</span> </span><span id="L-20"><a name="L-20"></a> <span class="n">d</span> <span class="o">=</span> <span class="p">{</span><span class="s1">&#39;y&#39;</span> <span class="p">:</span> <span class="mi">0</span><span class="p">}</span> </span><span id="L-21"><a name="L-21"></a> <span class="k">def</span> <span class="nf">g</span><span class="p">():</span> <span class="c1"># this is the closure</span> </span><span id="L-22"><a name="L-22"></a> <span class="n">d</span><span class="p">[</span><span class="s1">&#39;y&#39;</span><span class="p">]</span> <span class="o">+=</span> <span class="mi">1</span> </span><span id="L-23"><a name="L-23"></a> <span class="k">return</span> <span class="n">d</span><span class="p">[</span><span class="s1">&#39;y&#39;</span><span class="p">]</span> <span class="c1"># &quot;x&quot; is a (used) free variable, therefore it is captured in the closure</span> </span><span id="L-24"><a name="L-24"></a> <span class="c1"># end def g</span> </span><span id="L-25"><a name="L-25"></a> <span class="k">return</span> <span class="n">g</span> </span><span id="L-26"><a name="L-26"></a><span class="c1"># end def f</span> </span><span id="L-27"><a name="L-27"></a> </span><span id="L-28"><a name="L-28"></a><span class="n">g</span> <span class="o">=</span> <span class="n">f</span><span class="p">()</span> </span><span id="L-29"><a name="L-29"></a><span class="k">print</span> <span class="n">g</span><span class="o">.</span><span class="n">__closure__</span><span class="p">[</span><span class="mi">0</span><span class="p">]</span><span class="o">.</span><span class="n">cell_contents</span> </span><span id="L-30"><a name="L-30"></a><span class="k">print</span> <span class="n">g</span><span class="p">()</span> </span><span id="L-31"><a name="L-31"></a><span class="k">print</span> <span class="n">g</span><span class="o">.</span><span class="n">__closure__</span><span class="p">[</span><span class="mi">0</span><span class="p">]</span><span class="o">.</span><span class="n">cell_contents</span> </span><span id="L-32"><a name="L-32"></a><span class="k">print</span> <span class="n">g</span><span class="p">()</span> </span><span id="L-33"><a name="L-33"></a> </span><span id="L-34"><a name="L-34"></a><span class="c1"># in Kachayev&#39;s fn package</span> </span><span id="L-35"><a name="L-35"></a> </span><span id="L-36"><a name="L-36"></a><span class="kn">from</span> <span class="nn">fn</span> <span class="kn">import</span> <span class="n">_</span> </span><span id="L-37"><a name="L-37"></a><span class="kn">from</span> <span class="nn">fn.op</span> <span class="kn">import</span> <span class="n">zipwith</span> </span><span id="L-38"><a name="L-38"></a><span class="kn">from</span> <span class="nn">itertools</span> <span class="kn">import</span> <span class="n">repeat</span> </span><span id="L-39"><a name="L-39"></a> </span><span id="L-40"><a name="L-40"></a><span class="c1"># functions (be careful: in the interactive shell &quot;_&quot; means &quot;last output&quot;!)</span> </span><span id="L-41"><a name="L-41"></a> </span><span id="L-42"><a name="L-42"></a><span class="k">print</span> <span class="nb">list</span><span class="p">(</span><span class="nb">map</span><span class="p">(</span><span class="n">_</span> <span class="o">*</span> <span class="mi">2</span><span class="p">,</span> <span class="nb">range</span><span class="p">(</span><span class="mi">5</span><span class="p">)))</span> </span><span id="L-43"><a name="L-43"></a><span class="k">print</span> <span class="nb">list</span><span class="p">(</span><span class="nb">filter</span><span class="p">(</span><span class="n">_</span> <span class="o">&lt;</span> <span class="mi">10</span><span class="p">,</span> <span class="p">[</span><span class="mi">9</span><span class="p">,</span><span class="mi">10</span><span class="p">,</span><span class="mi">11</span><span class="p">]))</span> </span><span id="L-44"><a name="L-44"></a><span class="k">print</span> <span class="nb">list</span><span class="p">(</span><span class="n">zipwith</span><span class="p">(</span><span class="n">_</span> <span class="o">+</span> <span class="n">_</span><span class="p">)([</span><span class="mi">0</span><span class="p">,</span><span class="mi">1</span><span class="p">,</span><span class="mi">2</span><span class="p">],</span> <span class="n">repeat</span><span class="p">(</span><span class="mi">10</span><span class="p">)))</span> </span><span id="L-45"><a name="L-45"></a> </span><span id="L-46"><a name="L-46"></a><span class="k">print</span> <span class="n">_</span> <span class="o">+</span> <span class="n">_</span> <span class="o">*</span> <span class="n">_</span> </span><span id="L-47"><a name="L-47"></a> </span><span id="L-48"><a name="L-48"></a><span class="c1"># streams</span> </span><span id="L-49"><a name="L-49"></a> </span><span id="L-50"><a name="L-50"></a><span class="kn">from</span> <span class="nn">fn</span> <span class="kn">import</span> <span class="n">Stream</span> </span><span id="L-51"><a name="L-51"></a> </span><span id="L-52"><a name="L-52"></a><span class="n">s</span> <span class="o">=</span> <span class="n">Stream</span><span class="p">()</span> <span class="o">&lt;&lt;</span> <span class="p">[</span><span class="mi">1</span><span class="p">,</span><span class="mi">2</span><span class="p">,</span><span class="mi">3</span><span class="p">,</span><span class="mi">4</span><span class="p">,</span><span class="mi">5</span><span class="p">]</span> </span><span id="L-53"><a name="L-53"></a><span class="k">print</span> <span class="nb">list</span><span class="p">(</span><span class="n">s</span><span class="p">)</span> </span><span id="L-54"><a name="L-54"></a><span class="k">print</span> <span class="n">s</span><span class="p">[</span><span class="mi">1</span><span class="p">]</span> </span><span id="L-55"><a name="L-55"></a><span class="k">print</span> <span class="nb">list</span><span class="p">(</span><span class="n">s</span><span class="p">[</span><span class="mi">0</span><span class="p">:</span><span class="mi">2</span><span class="p">])</span> </span><span id="L-56"><a name="L-56"></a> </span><span id="L-57"><a name="L-57"></a><span class="n">s</span> <span class="o">=</span> <span class="n">Stream</span><span class="p">()</span> <span class="o">&lt;&lt;</span> <span class="nb">range</span><span class="p">(</span><span class="mi">6</span><span class="p">)</span> <span class="o">&lt;&lt;</span> <span class="p">[</span><span class="mi">6</span><span class="p">,</span><span class="mi">7</span><span class="p">]</span> </span><span id="L-58"><a name="L-58"></a><span class="k">print</span> <span class="nb">list</span><span class="p">(</span><span class="n">s</span><span class="p">)</span> </span><span id="L-59"><a name="L-59"></a> </span><span id="L-60"><a name="L-60"></a><span class="k">def</span> <span class="nf">gen</span><span class="p">():</span> </span><span id="L-61"><a name="L-61"></a> <span class="k">yield</span> <span class="mi">1</span> </span><span id="L-62"><a name="L-62"></a> <span class="k">yield</span> <span class="mi">2</span> </span><span id="L-63"><a name="L-63"></a> <span class="k">yield</span> <span class="mi">3</span> </span><span id="L-64"><a name="L-64"></a><span class="c1">#end def gen</span> </span><span id="L-65"><a name="L-65"></a> </span><span id="L-66"><a name="L-66"></a><span class="n">s</span> <span class="o">=</span> <span class="n">Stream</span><span class="p">()</span> <span class="o">&lt;&lt;</span> <span class="n">gen</span> <span class="o">&lt;&lt;</span> <span class="p">(</span><span class="mi">4</span><span class="p">,</span><span class="mi">5</span><span class="p">)</span> </span><span id="L-67"><a name="L-67"></a><span class="k">print</span> <span class="nb">list</span><span class="p">(</span><span class="n">s</span><span class="p">)</span> </span><span id="L-68"><a name="L-68"></a> </span><span id="L-69"><a name="L-69"></a><span class="c1"># lazy lists</span> </span><span id="L-70"><a name="L-70"></a> </span><span id="L-71"><a name="L-71"></a><span class="kn">from</span> <span class="nn">fn.iters</span> <span class="kn">import</span> <span class="n">take</span><span class="p">,</span> <span class="n">drop</span><span class="p">,</span> <span class="nb">map</span> </span><span id="L-72"><a name="L-72"></a><span class="kn">from</span> <span class="nn">operator</span> <span class="kn">import</span> <span class="n">add</span> </span><span id="L-73"><a name="L-73"></a> </span><span id="L-74"><a name="L-74"></a><span class="n">f</span> <span class="o">=</span> <span class="n">Stream</span><span class="p">()</span> </span><span id="L-75"><a name="L-75"></a><span class="n">fib</span> <span class="o">=</span> <span class="n">f</span> <span class="o">&lt;&lt;</span> <span class="p">[</span><span class="mi">0</span><span class="p">,</span> <span class="mi">1</span><span class="p">]</span> <span class="o">&lt;&lt;</span> <span class="nb">map</span><span class="p">(</span><span class="n">add</span><span class="p">,</span> <span class="n">f</span><span class="p">,</span> <span class="n">drop</span><span class="p">(</span><span class="mi">1</span><span class="p">,</span> <span class="n">f</span><span class="p">))</span> </span><span id="L-76"><a name="L-76"></a> </span><span id="L-77"><a name="L-77"></a><span class="k">print</span> <span class="nb">list</span><span class="p">(</span><span class="n">take</span><span class="p">(</span><span class="mi">10</span><span class="p">,</span> <span class="n">fib</span><span class="p">))</span> </span><span id="L-78"><a name="L-78"></a><span class="k">print</span> <span class="n">fib</span><span class="p">[</span><span class="mi">20</span><span class="p">]</span> </span><span id="L-79"><a name="L-79"></a><span class="k">print</span> <span class="nb">list</span><span class="p">(</span><span class="n">fib</span><span class="p">[</span><span class="mi">30</span><span class="p">:</span><span class="mi">35</span><span class="p">])</span> </span><span id="L-80"><a name="L-80"></a> </span><span id="L-81"><a name="L-81"></a><span class="c1"># optimized tail recursion</span> </span><span id="L-82"><a name="L-82"></a> </span><span id="L-83"><a name="L-83"></a><span class="kn">from</span> <span class="nn">fn</span> <span class="kn">import</span> <span class="n">recur</span> </span><span id="L-84"><a name="L-84"></a> </span><span id="L-85"><a name="L-85"></a><span class="nd">@recur.tco</span> </span><span id="L-86"><a name="L-86"></a><span class="k">def</span> <span class="nf">even</span><span class="p">(</span><span class="n">x</span><span class="p">):</span> </span><span id="L-87"><a name="L-87"></a> <span class="k">if</span> <span class="n">x</span> <span class="o">==</span> <span class="mi">0</span><span class="p">:</span> <span class="k">return</span> <span class="bp">False</span><span class="p">,</span> <span class="bp">True</span> <span class="c1"># i.e False =&gt; exit, True =&gt; return value</span> </span><span id="L-88"><a name="L-88"></a> <span class="k">return</span> <span class="n">odd</span><span class="p">,</span> <span class="p">(</span><span class="n">x</span><span class="o">-</span><span class="mi">1</span><span class="p">,)</span><span class="c1"># if it was True =&gt; call the same function, otherwise call another function</span> </span><span id="L-89"><a name="L-89"></a><span class="c1"># end def even</span> </span><span id="L-90"><a name="L-90"></a> </span><span id="L-91"><a name="L-91"></a><span class="nd">@recur.tco</span> </span><span id="L-92"><a name="L-92"></a><span class="k">def</span> <span class="nf">odd</span><span class="p">(</span><span class="n">x</span><span class="p">):</span> </span><span id="L-93"><a name="L-93"></a> <span class="k">if</span> <span class="n">x</span> <span class="o">==</span> <span class="mi">0</span><span class="p">:</span> <span class="k">return</span> <span class="bp">False</span><span class="p">,</span> <span class="bp">False</span> </span><span id="L-94"><a name="L-94"></a> <span class="k">return</span> <span class="n">even</span><span class="p">,</span> <span class="p">(</span><span class="n">x</span><span class="o">-</span><span class="mi">1</span><span class="p">,)</span> </span><span id="L-95"><a name="L-95"></a><span class="c1"># end def odd</span> </span><span id="L-96"><a name="L-96"></a> </span><span id="L-97"><a name="L-97"></a><span class="c1"># usually it would fail!</span> </span><span id="L-98"><a name="L-98"></a><span class="k">print</span> <span class="n">even</span><span class="p">(</span><span class="mi">100000</span><span class="p">)</span> </span><span id="L-99"><a name="L-99"></a> </span><span id="L-100"><a name="L-100"></a><span class="c1"># partial application</span> </span><span id="L-101"><a name="L-101"></a> </span><span id="L-102"><a name="L-102"></a><span class="kn">from</span> <span class="nn">fn</span> <span class="kn">import</span> <span class="n">F</span><span class="p">,</span> <span class="n">_</span> </span><span id="L-103"><a name="L-103"></a><span class="kn">from</span> <span class="nn">operator</span> <span class="kn">import</span> <span class="n">mul</span> </span><span id="L-104"><a name="L-104"></a> </span><span id="L-105"><a name="L-105"></a><span class="c1"># F(f, *args) is the partial application</span> </span><span id="L-106"><a name="L-106"></a><span class="c1"># like &quot;functools.partial&quot; but returns &quot;fn.F&quot;</span> </span><span id="L-107"><a name="L-107"></a> </span><span id="L-108"><a name="L-108"></a><span class="k">print</span> <span class="n">F</span><span class="p">(</span><span class="n">add</span><span class="p">,</span> <span class="mi">1</span><span class="p">)(</span><span class="mi">10</span><span class="p">)</span> </span><span id="L-109"><a name="L-109"></a> </span><span id="L-110"><a name="L-110"></a><span class="c1"># F &lt;&lt; F means function composition, therefore (F(f) &lt;&lt; g)(x) == f(g(x))</span> </span><span id="L-111"><a name="L-111"></a><span class="n">f</span> <span class="o">=</span> <span class="n">F</span><span class="p">(</span><span class="n">add</span><span class="p">,</span> <span class="mi">1</span><span class="p">)</span> <span class="o">&lt;&lt;</span> <span class="n">F</span><span class="p">(</span><span class="n">mul</span><span class="p">,</span> <span class="mi">100</span><span class="p">)</span> </span><span id="L-112"><a name="L-112"></a><span class="k">print</span> <span class="nb">list</span><span class="p">(</span><span class="nb">map</span><span class="p">(</span><span class="n">f</span><span class="p">,</span> <span class="p">[</span><span class="mi">0</span><span class="p">,</span> <span class="mi">1</span><span class="p">,</span> <span class="mi">2</span><span class="p">]))</span> </span><span id="L-113"><a name="L-113"></a><span class="k">print</span> <span class="nb">list</span><span class="p">(</span><span class="nb">map</span><span class="p">(</span><span class="n">F</span><span class="p">()</span> <span class="o">&lt;&lt;</span> <span class="nb">str</span> <span class="o">&lt;&lt;</span> <span class="p">(</span><span class="n">_</span> <span class="o">**</span> <span class="mi">2</span><span class="p">)</span> <span class="o">&lt;&lt;</span> <span class="p">(</span><span class="n">_</span> <span class="o">+</span> <span class="mi">1</span><span class="p">),</span> <span class="nb">range</span><span class="p">(</span><span class="mi">3</span><span class="p">)))</span> </span><span id="L-114"><a name="L-114"></a> </span><span id="L-115"><a name="L-115"></a><span class="c1"># pipes</span> </span><span id="L-116"><a name="L-116"></a> </span><span id="L-117"><a name="L-117"></a><span class="kn">from</span> <span class="nn">fn.iters</span> <span class="kn">import</span> <span class="nb">filter</span><span class="p">,</span> <span class="nb">range</span> </span><span id="L-118"><a name="L-118"></a> </span><span id="L-119"><a name="L-119"></a><span class="n">func</span> <span class="o">=</span> <span class="n">F</span><span class="p">()</span> <span class="o">&gt;&gt;</span> <span class="p">(</span><span class="nb">filter</span><span class="p">,</span> <span class="n">_</span> <span class="o">&lt;</span> <span class="mi">6</span><span class="p">)</span> <span class="o">&gt;&gt;</span> <span class="nb">sum</span> </span><span id="L-120"><a name="L-120"></a><span class="k">print</span> <span class="n">func</span><span class="p">(</span><span class="nb">range</span><span class="p">(</span><span class="mi">10</span><span class="p">))</span> </span><span id="L-121"><a name="L-121"></a> </span><span id="L-122"><a name="L-122"></a><span class="c1"># folding</span> </span><span id="L-123"><a name="L-123"></a> </span><span id="L-124"><a name="L-124"></a><span class="kn">from</span> <span class="nn">fn</span> <span class="kn">import</span> <span class="n">op</span> </span><span id="L-125"><a name="L-125"></a> </span><span id="L-126"><a name="L-126"></a><span class="n">folder</span> <span class="o">=</span> <span class="n">op</span><span class="o">.</span><span class="n">foldr</span><span class="p">(</span><span class="n">_</span> <span class="o">*</span> <span class="n">_</span><span class="p">,</span> <span class="mi">1</span><span class="p">)</span> </span><span id="L-127"><a name="L-127"></a><span class="k">print</span> <span class="n">op</span><span class="o">.</span><span class="n">foldl</span><span class="p">(</span><span class="n">_</span> <span class="o">+</span> <span class="n">_</span><span class="p">)([</span><span class="mi">1</span><span class="p">,</span> <span class="mi">2</span><span class="p">,</span> <span class="mi">3</span><span class="p">])</span> </span><span id="L-128"><a name="L-128"></a><span class="k">print</span> <span class="n">folder</span><span class="p">([</span><span class="mi">1</span><span class="p">,</span> <span class="mi">2</span><span class="p">,</span> <span class="mi">3</span><span class="p">])</span> </span><span id="L-129"><a name="L-129"></a> </span><span id="L-130"><a name="L-130"></a><span class="kn">from</span> <span class="nn">fn</span> <span class="kn">import</span> <span class="n">iters</span> </span><span id="L-131"><a name="L-131"></a> </span><span id="L-132"><a name="L-132"></a><span class="k">print</span> <span class="nb">list</span><span class="p">(</span><span class="n">iters</span><span class="o">.</span><span class="n">accumulate</span><span class="p">([</span><span class="mi">1</span><span class="p">,</span><span class="mi">2</span><span class="p">,</span><span class="mi">3</span><span class="p">],</span> <span class="n">add</span><span class="p">))</span> </span><span id="L-133"><a name="L-133"></a><span class="k">print</span> <span class="nb">list</span><span class="p">(</span><span class="n">iters</span><span class="o">.</span><span class="n">flatten</span><span class="p">([[</span><span class="mi">1</span><span class="p">,</span><span class="mi">2</span><span class="p">],</span> <span class="p">[</span><span class="mi">3</span><span class="p">,</span><span class="mi">4</span><span class="p">]]))</span> </span><span id="L-134"><a name="L-134"></a><span class="k">print</span> <span class="nb">list</span><span class="p">(</span><span class="n">iters</span><span class="o">.</span><span class="n">take</span><span class="p">(</span><span class="mi">10</span><span class="p">,</span> <span class="n">fib</span><span class="p">))</span> </span><span id="L-135"><a name="L-135"></a><span class="c1">#print list(iters.consume(iter(iters.range(10))), 5) ???</span> </span><span id="L-136"><a name="L-136"></a><span class="n">pn</span> <span class="o">=</span> <span class="n">iters</span><span class="o">.</span><span class="n">padnone</span><span class="p">([</span><span class="mi">10</span><span class="p">,</span><span class="mi">11</span><span class="p">])</span> </span><span id="L-137"><a name="L-137"></a><span class="k">print</span> <span class="nb">list</span><span class="p">(</span><span class="n">iters</span><span class="o">.</span><span class="n">take</span><span class="p">(</span><span class="mi">10</span><span class="p">,</span> <span class="n">pn</span><span class="p">))</span> </span><span id="L-138"><a name="L-138"></a> </span><span id="L-139"><a name="L-139"></a><span class="n">nc</span> <span class="o">=</span> <span class="n">iters</span><span class="o">.</span><span class="n">ncycles</span><span class="p">([</span><span class="mi">10</span><span class="p">,</span><span class="mi">11</span><span class="p">],</span> <span class="mi">3</span><span class="p">)</span> </span><span id="L-140"><a name="L-140"></a><span class="k">print</span> <span class="nb">list</span><span class="p">(</span><span class="n">iters</span><span class="o">.</span><span class="n">take</span><span class="p">(</span><span class="mi">10</span><span class="p">,</span> <span class="n">nc</span><span class="p">))</span> </span><span id="L-141"><a name="L-141"></a> </span><span id="L-142"><a name="L-142"></a><span class="n">rf</span> <span class="o">=</span> <span class="n">iters</span><span class="o">.</span><span class="n">repeatfunc</span><span class="p">(</span><span class="k">lambda</span><span class="p">:</span> <span class="s2">&quot;test&quot;</span><span class="p">,</span> <span class="mi">3</span><span class="p">)</span> </span><span id="L-143"><a name="L-143"></a><span class="k">print</span> <span class="nb">list</span><span class="p">(</span><span class="n">iters</span><span class="o">.</span><span class="n">take</span><span class="p">(</span><span class="mi">3</span><span class="p">,</span> <span class="n">rf</span><span class="p">))</span> </span><span id="L-144"><a name="L-144"></a> </span><span id="L-145"><a name="L-145"></a><span class="k">print</span> <span class="nb">list</span><span class="p">(</span><span class="n">iters</span><span class="o">.</span><span class="n">grouper</span><span class="p">(</span><span class="mi">3</span><span class="p">,</span> <span class="s2">&quot;ABCDEFG&quot;</span><span class="p">))</span> </span><span id="L-146"><a name="L-146"></a> </span><span id="L-147"><a name="L-147"></a><span class="k">print</span> <span class="nb">list</span><span class="p">(</span><span class="n">iters</span><span class="o">.</span><span class="n">roundrobin</span><span class="p">(</span><span class="s1">&#39;ABC&#39;</span><span class="p">,</span> <span class="s1">&#39;D&#39;</span><span class="p">,</span> <span class="s1">&#39;EF&#39;</span><span class="p">))</span> </span><span id="L-148"><a name="L-148"></a> </span><span id="L-149"><a name="L-149"></a><span class="p">(</span><span class="n">a</span><span class="p">,</span> <span class="n">b</span><span class="p">)</span> <span class="o">=</span> <span class="n">iters</span><span class="o">.</span><span class="n">partition</span><span class="p">(</span><span class="k">lambda</span> <span class="n">x</span><span class="p">:</span> <span class="n">x</span> <span class="o">%</span> <span class="mi">2</span> <span class="o">==</span> <span class="mi">1</span><span class="p">,</span> <span class="n">iters</span><span class="o">.</span><span class="n">range</span><span class="p">(</span><span class="mi">5</span><span class="p">))</span> </span><span id="L-150"><a name="L-150"></a><span class="k">print</span> <span class="nb">list</span><span class="p">(</span><span class="n">a</span><span class="p">),</span> <span class="nb">list</span><span class="p">(</span><span class="n">b</span><span class="p">)</span> </span><span id="L-151"><a name="L-151"></a> </span><span id="L-152"><a name="L-152"></a><span class="p">(</span><span class="n">a</span><span class="p">,</span> <span class="n">b</span><span class="p">)</span> <span class="o">=</span> <span class="n">iters</span><span class="o">.</span><span class="n">splitat</span><span class="p">(</span><span class="mi">2</span><span class="p">,</span> <span class="n">iters</span><span class="o">.</span><span class="n">range</span><span class="p">(</span><span class="mi">5</span><span class="p">))</span> </span><span id="L-153"><a name="L-153"></a><span class="k">print</span> <span class="nb">list</span><span class="p">(</span><span class="n">a</span><span class="p">),</span> <span class="nb">list</span><span class="p">(</span><span class="n">b</span><span class="p">)</span> </span><span id="L-154"><a name="L-154"></a> </span><span id="L-155"><a name="L-155"></a><span class="p">(</span><span class="n">a</span><span class="p">,</span> <span class="n">b</span><span class="p">)</span> <span class="o">=</span> <span class="n">iters</span><span class="o">.</span><span class="n">splitby</span><span class="p">(</span><span class="k">lambda</span> <span class="n">x</span><span class="p">:</span> <span class="n">x</span> <span class="o">%</span> <span class="mi">2</span> <span class="o">==</span> <span class="mi">0</span><span class="p">,</span> <span class="n">iters</span><span class="o">.</span><span class="n">range</span><span class="p">(</span><span class="mi">5</span><span class="p">))</span> </span><span id="L-156"><a name="L-156"></a><span class="k">print</span> <span class="nb">list</span><span class="p">(</span><span class="n">a</span><span class="p">),</span> <span class="nb">list</span><span class="p">(</span><span class="n">b</span><span class="p">)</span> </span><span id="L-157"><a name="L-157"></a> </span><span id="L-158"><a name="L-158"></a><span class="k">print</span> <span class="nb">list</span><span class="p">(</span><span class="n">iters</span><span class="o">.</span><span class="n">powerset</span><span class="p">([</span><span class="mi">1</span><span class="p">,</span> <span class="mi">2</span><span class="p">]))</span> </span><span id="L-159"><a name="L-159"></a><span class="k">print</span> <span class="nb">list</span><span class="p">(</span><span class="n">iters</span><span class="o">.</span><span class="n">pairwise</span><span class="p">(</span><span class="nb">range</span><span class="p">(</span><span class="mi">4</span><span class="p">)))</span> </span><span id="L-160"><a name="L-160"></a> </span><span id="L-161"><a name="L-161"></a><span class="c1"># and other similar nice stuff (see https://pypi.python.org/pypi/fn)</span> </span></pre></div> </td></tr></table>
Python, functional