ls

!cat output_data0.csv

import glob
from numpy import mean
from scipy.stats import sem

list_of_mean_fitness = []
list_of_stderr_fitness = []
list_of_mean_trait1 = []
list_of_stderr_trait1 = []
list_of_mean_trait2 = []
list_of_stderr_trait2 = []
list_of_mean_trait3 = []
list_of_stderr_trait3 = []

for gen in range(50):
    
    list_of_fitness = []
    list_of_trait1 = []
    list_of_trait2 = []
    list_of_trait3 = []
    
    for file_name in glob.glob("output_data*"):
        with open(file_name) as in_file:
            for line in in_file:
                split_line = line.split(",")
                if int(split_line[0]) == gen:
                    list_of_fitness.append(float(split_line[1]))
                    list_of_trait1.append(float(split_line[2]))
                    list_of_trait2.append(float(split_line[3]))
                    list_of_trait3.append(float(split_line[4]))
                    break
                    
    mean_fitness = mean(list_of_fitness)
    mean_trait1 = mean(list_of_trait1)
    mean_trait2 = mean(list_of_trait2)
    mean_trait3 = mean(list_of_trait3)
    
    stderr_fitness = 1.96*sem(list_of_fitness)
    stderr_trait1 = 1.96*sem(list_of_trait1)
    stderr_trait2 = 1.96*sem(list_of_trait2)
    stderr_trait3 = 1.96*sem(list_of_trait3)
    
    list_of_mean_fitness.append(mean_fitness)
    list_of_stderr_fitness.append(stderr_fitness)
    list_of_mean_trait1.append(mean_trait1)
    list_of_stderr_trait1.append(stderr_trait1)
    list_of_mean_trait2.append(mean_trait2)
    list_of_stderr_trait2.append(stderr_trait2)
    list_of_mean_trait3.append(mean_trait3)
    list_of_stderr_trait3.append(stderr_trait3)
    
errorbar(x=range(len(list_of_mean_fitness)),
            y=list_of_mean_fitness,
            yerr=list_of_stderr_fitness)

1.96 * array([1, 2, 3])