complex « List « Python Data Type Q&A

1. Best way to construct a "complex" data structure in Python    stackoverflow.com

I need to construct a tool that will be used to create field mappings (between tables) in the most automated manner possible. Here is the deal: imagine a table being appended to ...

2. Python: complex list comprehensions where one var depends on another (x for x in t[1] for t in tests)    stackoverflow.com

I want to do something like:

all = [ x for x in t[1] for t in tests ]

[ ("foo",[a,b,c]), ("bar",[d,e,f]) ]

all = [a,b,c,d,e,f]

3. Python beginner confused by a complex line of code    stackoverflow.com

I understand the gist of the code, that it forms permutations; however, I was wondering if someone could explain exactly what is going on in the return statement.

def perm(l):
   ...

4. Plotting a list of Complex nos on Z-plane in python    stackoverflow.com

I tried:

plot(z)

plot( z.real, z.imag )

5. python: how to sort a complex list on two different keys    stackoverflow.com

I have a weird list built in the following way:

[[name_d, 5], [name_e, 10], [name_a, 5]] 

6. Write a list of Complex Numbers as Binary Data    stackoverflow.com

I'm trying to output some data from a python script to a binary file. If I have a list of floats I've been using this

out_file = open("filename", "wb")
float_array.array("f", [])
float_array.fromlist(mylist)
float_array.tofile(out_file)
out_file.close()

7. A complex ordering algorithm for a Python list?    stackoverflow.com

I need to order a list of comments so they appear in their threaded order. Each comment has a:

• Top parent comment (for queries)
• Parent comment
• Indentation level

8. equivalent for loop expression for complex list comprehension    stackoverflow.com

For example, following list comprehension could be rephrased as the for loop below.

>>> [(x,y) for x in range(5) if x % 2 == 0 for y in range(5) if y ...

9. sorting list of complex numbers    bytes.com

I can sort by the real parts just fine: > >>lst.sort(key=lambda x: x.real) >>pprint.pprint(lst) [2.6000000000000001j, 20j, (1+2.73j), (1+21j), (2+2.8600000000000003j), (2+22j), (3+2.9900000000000002j), (3+23j), (4+3.1200000000000001j), (4+24j), (5+3.25j), (5+25j), (6+26j), (6+3.3799999999999999j), (7+27j), (7+3.5100000000000002j), (8+28j), (8+3.6400000000000001j), (9+3.77j), (9+29j)] > but how do I then do a secondary sort by the imaginary part, preserving the existing ordering on the real parts? Seems like I have to ...

10. %d in more complex lists    python-forum.org

11. How to sort a complex list by the second element    python-forum.org

Once more I need help, I create a list with the following structure ['word1', word1_freq, [list1], 'word2' ,word2_freq, [list2], ....] This work fine, but the problem is that now I need to sort the list according to the word*_freq, is there anyway of doing this directly? Or I have to create another type of structure? And of what kind? Thank you, ...

12. list comprehension with complex numbers    python-forum.org