numpy – TypeError: only length-1 arrays can be converted to Python scalars while plot showing

numpy – TypeError: only length-1 arrays can be converted to Python scalars while plot showing

The error only length-1 arrays can be converted to Python scalars is raised when the function expects a single value but you pass an array instead.

If you look at the call signature of np.int, youll see that it accepts a single value, not an array. In general, if you want to apply a function that accepts a single element to every element in an array, you can use np.vectorize:

import numpy as np
import matplotlib.pyplot as plt

def f(x):
    return np.int(x)
f2 = np.vectorize(f)
x = np.arange(1, 15.1, 0.1)
plt.plot(x, f2(x))
plt.show()

You can skip the definition of f(x) and just pass np.int to the vectorize function: f2 = np.vectorize(np.int).

Note that np.vectorize is just a convenience function and basically a for loop. That will be inefficient over large arrays. Whenever you have the possibility, use truly vectorized functions or methods (like astype(int) as @FFT suggests).

Use:

x.astype(int)

Here is the reference.

numpy – TypeError: only length-1 arrays can be converted to Python scalars while plot showing

dataframe[column].squeeze() should solve this. It basically changes the dataframe column to a list.