How to break a list into two separate lists to use in Gnuplot python?

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How to break a list into two separate lists to use in Gnuplot python?

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#1 by (1 votes)

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A feature of online gnuplot allows you to place your data in two columns separated by space, and it understands how the "x" and "y" axes

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I'm trying to use python gnuplot. Assuming it would be similar to the online feature, I put "#" in what was not given and tried to plot. However, I found only tutorial asking to separate the x-axis from the y-axis into two separate lists.

I have a list (which can also be in string format), as in the example below:

lista = ['59.99167\t-3180\r\n', '60.00000\t-3181\r\n']

string = 59.99167 -3180 60.00000 -3181

My questions are: how do I easily break my list (in the "\ t" character) or string in two new lists (x and y), with my data separated? Is there any way I can use gnuplot python without having to do this, as it does in gnuplot online?

python plot

asked by anonymous 17.06.2018 / 22:24

1 answer

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score 1 · Accepted Answer

I do not know the gnuplot, but it's not difficult to separate your list into two lists with x and y values in Python.

The first step is to break the elements from the '\ t'. For this, just use split : this function divides a string into a list of strings separated by the character or substring passed to it. We can use a list understanding to apply the operation to all the strings of the list in a single line:

lista = ['59.99167\t-3180\r\n', '60.00000\t-3181\r\n']
lista_split = [dado.split('\t') for dado in lista]
print(lista_split)
# [['59.99167', '-3180\r\n'], ['60.00000', '-3181\r\n']]

We now have a list of lists, but not well in the format we want. To turn our list into two separate lists x and y , we can use zip . It gives us two tuples, so if we really want lists just say:

x, y = zip(*lista_split)
x, y = list(x), list(y)
print(x)
# ['59.99167', '60.00000']
print(y)
# ['-3180\r\n', '-3181\r\n']

As you can see, we now have x and y more or less as we wanted, but I imagine you want the value as float or int , not as strings (including whitespace, case of y ). Once again, list comprehensions can provide a quick fix:

x = [float(valor) for valor in x]
print(x)  # [59.99167, 60.0]
y = [float(valor) for valor in y]
print(y)  # [-3180.0, -3181.0]

Translating:

x is now as follows:
a list, where:
For each element valor of x , one of the elements of the new list corresponds to float(valor)