循环遍历二维数组，错误 TypeError: 'int' object is not subscriptable

Question

I need to loop with y 2d array but it gives me error, it tells me: Traceback (most recent call last): File "plot.py", line 18, in y[k][j] = y[k][j]+1 TypeError: 'int' object is not subscriptable

import matplotlib.pyplot as plt
import math
import numpy as np
jo =[20,30,40,50,60,70]
for k in jo:
    x=[]
    mo = str(k)
    migo = "".join(["./",mo,"/result_no"])
    with open(migo) as f:
        for line in f:
            x.append(float(line))
    y = [jo][0]*120
 #   print(y) 
    for i in range(len(x)):
        j = int(x[i])
        y[k][j] = y[k][j]+1
    b = [0]*120
    for i in range(len(y[k])):
            if (k==10):
                if (y[k][i]!=0):
                    b[i] = - math.log( y[k][i] )
            if (k!=10):
                if (y[k][i]!=0):
                        b[i] = -math.log( y[k][i] )-0.01*(i-k)*(i-k)
    alp = b[:]
    for i in range(len(alp)):
            if (alp[i]==0): 
                b.remove(0) 
    plt.show()
    #fy = plt.plot(y)
    ft = plt.plot(b)
plt.show()

Answer 1

If you run

jo = [20,30,40,50,60,70]                                                        
y = [jo][0]*120                                                                 
print(y)

you will see that y is a one-dimensional list containing 720 elements, which is 120 * len(jo) . This is because in the line y = [jo][0]*120 , you create a nested list [[20, 30, 40, 50, 60, 70]] , then take the first element of that list, which is [20, 30, 40, 50, 60, 70] (or jo ), and repeat it 120 times.

Since you are looking for an array of 120 rows, len(jo) columns, you could create this like:

y = [[0] * len(jo)] * 120

To access the elements according to your code sample, you would modify your for loop to also get the index of the element in jo , ie:

for idx, k in enumerate(jo):
    x=[]
    mo = str(k)
    migo = "".join(["./",mo,"/result_no"])
    with open(migo) as f:
        for line in f:
            x.append(float(line))
    y = [[0] * len(jo)] * 120
 #   print(y) 
    for i in range(len(x)):
        j = int(x[i])
        y[idx][j] = y[idx][j]+1

You may consider whether y is supposed to be defined inside the for loop - I suspect not.