Python 3.3.3 (v3.3.3:c3896275c0f6, Nov 16 2013, 23:39:35) 
[GCC 4.2.1 (Apple Inc. build 5666) (dot 3)] on darwin
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# define a lambda function and check its type (function, daaah)
>>> type(lambda x:x+2)
<class 'function'>
# define a lambda function and immediately call it with a parameter
>>> (lambda x:x+2)(6)
8
>>> y=3
>>> (lambda x:x+y)(6)
9
# define a lambda function and give it a name; equivalent to "def f(): ..."
>>> f = (lambda x:x+y)
>>> f(3)
6
# example 1
>>> def make_pow(n):
    return lambda x:pow(x,n)
>>> make_pow(2)
<function make_pow.<locals>.<lambda> at 0x102450f80>
>>> sqr = make_pow(2)
>>> sqr(3)
9
>>> cub = make_pow(3)
>>> cub(3)
27
>>> make_pow(2)(3)
9
>>> type(sqr)
<class 'function'>
# example 2
>>> sorted(["red","lefty","poncho","dafna"])
['dafna', 'lefty', 'poncho', 'red']
>>> sorted(["red","lefty","poncho","dafna"],key=len)
['red', 'lefty', 'dafna', 'poncho']
>>> sorted(["red","lefty","poncho","dafna"],key=lambda s:len(s))
['red', 'lefty', 'dafna', 'poncho']
>>> sorted(["red","lefty","poncho","dafna"],key=lambda s:s[::-1])
['dafna', 'red', 'poncho', 'lefty']
>>> sorted(["romeo","red","almo"],key=lambda s:s[0])
['almo', 'romeo', 'red']
>>> def first_char(s):
    return s[0]
>>> sorted(["romeo","red","almo"],key=first_char)
['almo', 'romeo', 'red']
>>> sorted(["3","222","11"],key=int)
['3', '11', '222']
# example 3
>>> def compose(f1,f2):
    return lambda x:f1(f2(x))
>>> h1 = compose(lambda x:x+1,lambda x:2*x)
>>> h1(3)
7
>>> h1 = compose(lambda x:2*x,lambda x:x+1)
>>> h1(3)
8
# example 4
>>> def info(lst,func,*params):
    return func(lst,*params)
>>> info([10,12,14,13,11],lambda l: sum([e for e in l if e>12]))
27
>>> info([10,12,14,13,11],lambda l: [e for e in l if e>12])
[14, 13]
>>> info([10,12,14,13,11],lambda l,i: sorted(l)[i-1],2)
11
>>> info([10,12,14,13,11],lambda l,i,j: l[i] if j<i else l[j],2,0)
14