CODEWITHSUNDEEP
pythonrandom
bathtub2007
bathtub2007

Reputation: 91

Python - Generating a New List Randomly From Two Other Lists

I have two lists, high and low bounds, that I would like to use as bounds to create a new list randomly between those values.

LOW     HIGH
19.35   45.04
18.09   44.05
17.44   42.07
16.46   41.95
18.38   43.45
20.78   46.04
24.99   49.12
25.22   50.94
24.67   49.32

I am trying to create a new list that has the length of list but has random values between each LOW and HIGH pair.

A new list might look like:

NEW LIST
38.26
33.70
18.47
41.35
36.77
21.95
25.23
29.18
49.32

Any help is appreciated, thanks!

So far this is what I have but it doesn't step down a row to update the lower and upper bounds:

Low = pd.Series(data['LOW']).values
High = pd.Series(data['HIGH']).values

newlist = []

for i in range(0, 8):
        newlist = random.uniform(Low, High)

Upvotes: 0

Views: 396

Answers (3)

Konstantinos Katsantonis
Konstantinos Katsantonis

Reputation: 1450

import random 
HIGH = [45.04, 44.05, 42.07, 41.95, 43.45, 46.04, 49.12, 50.94, 49.32] 
LOW = [19.35, 18.09, 17.44, 16.46, 18.38, 20.78, 24.99, 25.22, 24.67]  
result = []

for low,high in zip(LOW,HIGH): 
    result.append(random.uniform(low,high))

print(result)

Example output:

[20.23415150413731, 31.21737764031939, 33.39330466412157, 29.23878916462911, 33.23211876295469, 35.20524920370517, 32.21931456613152, 44.07717212042314, 48.56798614652851]

Upvotes: 0

AMC
AMC

Reputation: 2702

All hail the power of broadcasting!

import pandas as pd
import random
import numpy as np

# example data
lows = pd.Series(np.random.uniform(0, 50, 10))
highs = pd.Series(np.random.uniform(0, 50, 10))

nums_arr = random.uniform(low=lows, high=highs)

I especially like this solution because it directly creates a Series, no conversions necessary.

A few comments on your code:

1)

Variable names should generally follow the lower_case_with_underscores style. See PEP 8 for more on Python style.

2)

Low = pd.Series(data['LOW']).values
High = pd.Series(data['HIGH']).values

From the rest of the code you showed me, you already know that data is a DataFrame. Getting a column from a DataFrame (e.x: data['LOW']) returns a Series, so the call to pd.Series() is redundant. It also isn't clear why you then call .values().

Bear in mind that using Series.values is discouraged. From the docs:

Warning: We recommend using Series.array or Series.to_numpy(), depending on whether you need a reference to the underlying data or a NumPy array.

3)

newlist = []

for i in range(0, 8):
        newlist = random.uniform(Low, High)

I'm really struggling to find the words to explain this one. random.uniform is a function which takes two numbers, and produces a random float between the first two. In this case, however, random.uniform is operating on two Series, thanks to the magic of broadcasting. This is why despite not looking like it makes much sense, the code doesn't actually produce an error or crash.

Notice also that the code above doesn't actually do anything with the result in newlist, nor does newList depend at all on the variable i.

My guess is that you had something like this in mind:

# notice the variable name
new_nums_list = []

for i in range(low.size):
    curr_rand_num = random.uniform(low[i], high[i])
    new_nums_list.append(curr_rand_num)

Which could have also been written:

new_nums_list = [random.uniform(low[i], high[i]) for i in range(low.size)]

Thanks to the power of zip(), we could do even better:

new_nums_list = [random.uniform(curr_low, curr_high) for curr_low, curr_high in zip(low, high)]

Any further questions? :)

Upvotes: 1

PL200
PL200

Reputation: 741

I think this should give you the solution you're after. The code below puts the low and high lists into a list of its own, and iterates through each index, randomly picking one.

from random import randint

low = [19.35, 18.09, 17.44, 16.46, 18.38, 20.78, 24.99, 25.22, 24.67]
high = [45.04, 44.05, 42.07, 41.95, 43.45, 46.04, 49.12, 50.94, 49.32]

lists = [low, high]
newlist = []
for i in range(0, len(low)):
    newlist.append(lists[randint(0, 1)][i])

This is an output I just generated, for reference:

[19.35, 18.09, 42.07, 16.46, 18.38, 46.04, 24.99, 25.22, 49.32]

Upvotes: 0

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