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Python Data Type Q&A » List » lambda 

1. How do I create a list of Python lambdas (in a list comprehension/for loop)?    stackoverflow.com

I want to create a list of lambda objects from a list of constants in Python; for instance:

listOfNumbers = [1,2,3,4,5]
square = lambda x: x * x
listOfLambdas = [lambda: square(i) for i ...

2. How to run an operation on a collection in Python and collect the results?    stackoverflow.com

How to run an operation on a collection in Python and collect the results? So if I have a list of 100 numbers, and I want to run a function like this ...

3. Efficient way to use python's lambda, map    stackoverflow.com

I need to store a big list of integers in Bigtable(db). For efficiency I am storing them as diff between 2 consecutive items. for eg:

 original_list = [1005, 1004, 1003, 1004, 1006] ...

4. lambda versus list comprehension performance    stackoverflow.com

I recently posted a question using a lambda function and in a reply someone had mentioned lambda is going out of favor, to use list comprehensions instead. I am relatively new ...

5. Help with python list-comprehension    stackoverflow.com

A simplified version of my problem: I have a list comprehension that i use to set bitflags on a two dimensional list so:

s = FLAG1 | FLAG2 | FLAG3
[[c.set_state(s) for c in ...

6. List filtering: list comprehension vs. lambda + filter    stackoverflow.com

I happened to find myself having a basic filtering need: I have a list and I have to filter it by an attribute of the items. My code looked like this:

my_list = ...

7. lambda push to a list then invoking - output is not as expected    stackoverflow.com

All:

def a(p): 
    return p+1 

def gen(func, k=100): 
    l= [] 
    for x in range(k): 
      ...

8. assign a retrievable unique ID to a changing lambda list in python?    stackoverflow.com

def a(p): return p + 1

def b(p): return p + 2

def c(p): return p + 3

l= [a,b,c]

import itertools
ll = itertools.combinations(l, 2)

[x for x in ll]
[(<function a at 0x00CBD770>, <function b at ...

9. Generating a list of functions in python    stackoverflow.com

I have the following pyhton code that generates a list of anonymous function:

basis = [ (lambda x: n*x) for n in [0, 1, 2] ]     
print basis[0](1)
I ...

10. What is the Pythonic way of reordering a list consisting of dicts?    stackoverflow.com

I have the the following list:

list = [{'nr' : 2, 'name': 'streamname'}, {'nr' : 3,'name': 'streamname'}, {'nr' : 1, 'name': 'streamname'}]
So how would I reorder it to become like this ...

11. Evaluating a list of python lambda functions only evaluates the last list element    stackoverflow.com

I have a list of lambda functions I want to evaluate in order. I'm not sure why, but only the last function gets evaluated. Example below:

  >>> def f(x,z):
  ...

12. Python: Lambda function in List Comprehensions    stackoverflow.com

Why is the output of the following two list comprehensions different, even though f and the lambda function are the same ?

f = lambda x: x*x
[f(x) for x in range(10)]
and
[lambda x: ...

13. Python map vs list comprehension    stackoverflow.com

When comparing these, which do you think is more intuitive / easier to read?

>>> [ord(i) for i in 'some string']
[115, 111, 109, 101, 32, 115, 116, 114, 105, 110, 103]

>>> map(ord,'some ...

14. split a list by a lambda function in python    stackoverflow.com

Is there any version of split that works on generic list types? For example, in Haskell

Prelude> import Data.List.Split
Prelude Data.List.Split> splitWhen (==2) [1, 2, 3]
[[1],[3]]

15. list of python lambda functions w/o partial    stackoverflow.com

I have been trying to generate a list of lambda functions in python using list comprehension. but it didn't work, for example

fl=[lambda x: x**i for i in range(5)]
i have check ...

16. Python get N elements from a list at a time using lambda    stackoverflow.com

Imagine I have a list like this:

a = [1,2,3,4,5,6]
Using a lambda function, I would like to return two elements at a time, so the result would be:
res = [[1,2], [2,3], [3,4], ...

17. Weird behavior: Lambda inside list comprehension    stackoverflow.com

In python 2.6:

[x() for x in [lambda: m for m in [1,2,3]]]
results in:
[3, 3, 3]
I would expect the output to be [1, 2, 3]. I get the exact same problem even ...

18. Python list operations , Lambda Expression    stackoverflow.com

def myFunction(name):
    index = 0
    list = self.getList()
    index = (x => x.name == name)
    return index
i want to ...

19. List of lambda functions    python-forum.org

>>> params = [1, 2] >>> z = [None, None] >>> for i in range(len(z)): ... z[i] = lambda x, p=i: x**params[p] ... >>> x = range(5) >>> for i in x: ... print z[0](i), z[1](i) ... 0 0 1 1 2 4 3 9 4 16 >>>

20. weird behaviour in list of lambda functions    python-forum.org

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