How can I eliminate the error 'float' object is not subscriptable?

Question

I am trying to use ρ_mix object inside the function def odes(x, V) but this message is appeared - 'float' object is not subscriptable. ρ_mix was created by the first value of an array of different sized-objects. The size of ρ_mix is (50,). The full error message is:

Traceback (most recent call last):
File ~\OneDrive - uowm.gr\Desktop\draft\untitled0.py:92 in <module> sol = odeint(odes, x0, V)
 
File ~\anaconda3\lib\site-packages\scipy\integrate\odepack.py:241 in odeint output = _odepack.odeint(func, y0, t, args, Dfun, col_deriv, ml, mu,
  
File ~\OneDrive - uowm.gr\Desktop\draft\untitled0.py:74 in odes d_mix = np.array([i[0] for i in gas_new(T, 101325)])
  
File ~\OneDrive - uowm.gr\Desktop\draft\untitled0.py:74 in <listcomp> d_mix = np.array([i[0] for i in gas_new(T, 101325)])

TypeError: 'float' object is not subscriptable

import numpy as np
from scipy.integrate import odeint
import matplotlib.pyplot as plt
import cantera as ct
T = np.linspace(873.15, 1023.15, 50)
def gas(T, P): # Kelvin, Pascal
    
    gas = ct.Solution('gri30.xml','gri30_mix')
    molar_ratio = {'CH4': 0.3, 'CO2':0.2, 'H2O':0.0, 'H2':0.0, 'CO':0.0, 'Ar': 0.5}
    gas.TPX = T, P, molar_ratio
    feed = gas['CH4', 'CO2', 'H2O', 'H2', 'CO', 'Ar']
    
    ρ_mix = feed.density # kg/m3
    cp_mix_mass = feed.cp_mass # J/Kg/K 
    Dm_mole = feed.mix_diff_coeffs_mole # m2/s mixture-averaged diffusion coefficients
    λg = feed.thermal_conductivity # J/s/m/K average gas thermal conductivity
    μ = feed.viscosity # Pa.s
    Ci = feed.concentrations*1e03 # mol/m3
    return np.array([ρ_mix, cp_mix_mass, Dm_mole, λg, μ, Ci], dtype=object)

gas_new = np.vectorize(gas)
ρ_mix = [i[0] for i in gas_new(T, 101325)]

def odes (x, V):

    # assign each ODE (ordinary differential equation) to a vector element
    # states (2): molar rate mol/L for 3 components (1*3) | temperature (K) (1)
    Fa = x[0]
    Fb = x[1]
    Fc = x[2]
    T = x[3]

    # equations used
    k1a, k2a = k(T)[0], k(T)[1]
    ρ_mix = [i[0] for i in gas_new(T, 101325)]

    Ft = Fa + Fb + Fc
    Ca = Cto*(Fa/Ft)*(To/T)*(P/Po)
    Cb = Cto*(Fb/Ft)*(To/T)*(P/Po)
    Cc = Cto*(Fc/Ft)*(To/T)*(P/Po)
    r1a = -k1a*Ca*ρ_mix
    r2a = -k2a*Ca**2*ρ_mix

    # define each ODE
    dFadV = r1a + r2a
    dFbdV = -r1a
    dFcdV = -r2a/2
    dTdV = (Ua*(Ta-T)+(-r1a)*(-dH_r1A)+(-r2a)*(-dH_r2A))/(Cpa*Fa+Cpb*Cpb+Cpc*Fc)

    return np.array([dFadV, dFbdV, dFcdV, dTdV], dtype='float64')

x0 = np.array([100, 0.1, 0.1, 450], dtype='float64')

V = np.linspace(0, 1, 10000)

sol = odeint(odes, x0, V)

Fa, Fb, Fc, T = sol.T

Answer 1

T = x[3]
# equations used
k1a, k2a = k(T)[0], k(T)[1]
?_mix = [i[0] for i in gas_new(T, 101325)]

Is this T here an array just like this T = np.linspace(873.15, 1023.15, 50)? Because as far as I can see x[3] would be simply be 450, not a linspace so there is nothing to be vectorised with gas_new