CODEWITHSUNDEEP
pythonpython-3.xdictionarynested-lists
MoonBoi9001
MoonBoi9001

Reputation: 65

How can I make this more scalable for large list of items?

So I'm trying to make a large list containing all the elements I need, as seen in the output of the following code:

set = [1, 5, 15, 30, 60, 240, 360, 720, 1440, 10080]
ShortEMASet = []
LongEMASet = []
MACDSet = []
SignalSet = []

SetofSets = [ShortEMASet, LongEMASet, MACDSet, SignalSet]

for x in set:
    ShortEMASet.append("ShortEMA" + str(x))
    LongEMASet.append("LongEMASet" + str(x))
    MACDSet.append("MACDSet" + str(x))
    SignalSet.append("SignalSet" + str(x))
    
SetofSets

This returns the output

[['ShortEMA1',
  'ShortEMA5',
  'ShortEMA15',
  'ShortEMA30',
  'ShortEMA60',
  'ShortEMA240',
  'ShortEMA360',
  'ShortEMA720',
  'ShortEMA1440',
  'ShortEMA10080'],
 ['LongEMASet1',
  'LongEMASet5',
  'LongEMASet15',
  'LongEMASet30',
  'LongEMASet60',
  'LongEMASet240',
  'LongEMASet360',
  'LongEMASet720',
  'LongEMASet1440',
  'LongEMASet10080'],
 ['MACDSet1',
  'MACDSet5',
  'MACDSet15',
  'MACDSet30',
  'MACDSet60',
  'MACDSet240',
  'MACDSet360',
  'MACDSet720',
  'MACDSet1440',
  'MACDSet10080'],
 ['SignalSet1',
  'SignalSet5',
  'SignalSet15',
  'SignalSet30',
  'SignalSet60',
  'SignalSet240',
  'SignalSet360',
  'SignalSet720',
  'SignalSet1440',
  'SignalSet10080']]

However the problem is, if my variable SetofSets contained 100+ lists inside it, then it would be SUPER tedious to write this out 100+ times, how can I make it more scalable?

I tried the following:

set = [1, 5, 15, 30, 60, 240, 360, 720, 1440, 10080]
ShortEMASet = []
LongEMASet = []
MACDSet = []
SignalSet = []

SetofSets = [ShortEMASet, LongEMASet, MACDSet, SignalSet]
for x in set:
    for i in SetofSets:
        SetofSets[i].append(str(SetofSets[i]) + str(x))
SetofSets

Which fails due to this error:

---------------------------------------------------------------------------
TypeError                                 Traceback (most recent call last)
<ipython-input-641-81831a6939e2> in <module>
      8 for x in set:
      9     for i in SetofSets:
---> 10         SetofSets[i].append(str(SetofSets[i]) + str(x))
     11 SetofSets

TypeError: list indices must be integers or slices, not list

Upvotes: 2

Views: 103

Answers (2)

Andrej Kesely
Andrej Kesely

Reputation: 195653

You can do nested for-loop:

lst = [1, 5, 15, 30, 60, 240, 360, 720, 1440, 10080]
names = ["ShortEMASet", "LongEMASet", "MACDSet", "SignalSet"]

out = []
for n in names:
    out.append([])
    for l in lst:
        out[-1].append(n + str(l))

print(out)

Prints:

[
    [
        "ShortEMASet1",
        "ShortEMASet5",
        "ShortEMASet15",
        "ShortEMASet30",
        "ShortEMASet60",
        "ShortEMASet240",
        "ShortEMASet360",
        "ShortEMASet720",
        "ShortEMASet1440",
        "ShortEMASet10080",
    ],
    [
        "LongEMASet1",
        "LongEMASet5",
        "LongEMASet15",
        "LongEMASet30",
        "LongEMASet60",
        "LongEMASet240",
        "LongEMASet360",
        "LongEMASet720",
        "LongEMASet1440",
        "LongEMASet10080",
    ],
    [
        "MACDSet1",
        "MACDSet5",
        "MACDSet15",
        "MACDSet30",
        "MACDSet60",
        "MACDSet240",
        "MACDSet360",
        "MACDSet720",
        "MACDSet1440",
        "MACDSet10080",
    ],
    [
        "SignalSet1",
        "SignalSet5",
        "SignalSet15",
        "SignalSet30",
        "SignalSet60",
        "SignalSet240",
        "SignalSet360",
        "SignalSet720",
        "SignalSet1440",
        "SignalSet10080",
    ],
]

Or list-comprehension:

out = [[n + str(l) for l in lst] for n in names]
print(out)

EDIT: You can create a dictionary instead of a list:

lst = [1, 5, 15, 30, 60, 240, 360, 720, 1440, 10080]
names = ["ShortEMASet", "LongEMASet", "MACDSet", "SignalSet"]


out = {}
for n in names:
    for l in lst:
        out.setdefault(n, []).append(n + str(l))

print(out)

Prints:

{
    "ShortEMASet": [
        "ShortEMASet1",
        "ShortEMASet5",
        "ShortEMASet15",
        "ShortEMASet30",
        "ShortEMASet60",
        "ShortEMASet240",
        "ShortEMASet360",
        "ShortEMASet720",
        "ShortEMASet1440",
        "ShortEMASet10080",
    ],
    "LongEMASet": [
        "LongEMASet1",
        "LongEMASet5",
        "LongEMASet15",
        "LongEMASet30",
        "LongEMASet60",
        "LongEMASet240",
        "LongEMASet360",
        "LongEMASet720",
        "LongEMASet1440",
        "LongEMASet10080",
    ],
    "MACDSet": [
        "MACDSet1",
        "MACDSet5",
        "MACDSet15",
        "MACDSet30",
        "MACDSet60",
        "MACDSet240",
        "MACDSet360",
        "MACDSet720",
        "MACDSet1440",
        "MACDSet10080",
    ],
    "SignalSet": [
        "SignalSet1",
        "SignalSet5",
        "SignalSet15",
        "SignalSet30",
        "SignalSet60",
        "SignalSet240",
        "SignalSet360",
        "SignalSet720",
        "SignalSet1440",
        "SignalSet10080",
    ],
}

Then you can call:

print(out["ShortEMASet"])

to print:

[
    "ShortEMASet1",
    "ShortEMASet5",
    "ShortEMASet15",
    "ShortEMASet30",
    "ShortEMASet60",
    "ShortEMASet240",
    "ShortEMASet360",
    "ShortEMASet720",
    "ShortEMASet1440",
    "ShortEMASet10080",
]

Upvotes: 4

Dmitry T.
Dmitry T.

Reputation: 701

Just a small mistake:

for x in set:
    for i in SetofSets:
        SetofSets[i].append(str(SetofSets[i]) + str(x))

should be

for x in set:
    for i in SetofSets:
        i.append(str(SetofSets[i]) + str(x))

P.S. Off-top, but generally I'd advice you to avoid calling a variable with a built-in type (set is a built-in type, I probably noticed the `set is highlighted differently) and follow the PEP-8 formatting.

Upvotes: 2

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