Saving arrays of float in a .txt file in columns

Saving arrays of float in a .txt file in columns

Problem Description:

I have 15 arrays of float (130 x 150) each, called (a,b,c,d,..,q).
And I would like to save these to a .txt file called array.txt.
The format should be 15 columns for 19500 rows, where array a occupy the entire first column, b the second etc..
The elements from each array should be picked rows by rows.

Can someone help me with this? How can I do it? I was thinking with 15 for loops for each element of the arrays, but I think that is not smart and better methods are possible.


Solution – 1

import numpy as np
import pandas as pd
a = [1,2,3,4,5]
b = [6,7,8,9,10]
c = [11,12,13,14,15]
l = zip(a,b,c)
df = pd.DataFrame(l, columns=["a","b","c"])
np.savetxt(r'array.txt', df.values, fmt='%f')

This will combine the lists "a","b" and "c" and write them to a text file named array.txt

Solution – 2

I too would normally recommend using Pandas for these operations, but if you are required to use Numpy, you could try something like this:

import numpy as np
import pandas as pd

# Set up dummy-problem
data = {key: np.random.random((130, 150)) for key in "ABCDEFGHIJKLMNOPQ"}
# You would probably create a list containing the variables [a, b, c, ..., q]

# Concatenate results and save data
result = np.concatenate([a.flatten("F")[:, None] for a in data.values()], axis=1)
np.savetxt("data.txt", result)

# PS! To read as a Pandas DataFrame, use
pd.DataFrame({key: a.flatten("F") for key, a in data.items()})
Rate this post
We use cookies in order to give you the best possible experience on our website. By continuing to use this site, you agree to our use of cookies.