如何将字符串'[1,2,3,4]'转化为列表[1,2,3,4]

将字符串'[1,2,3,4]'转化为列表[1,2,3,4]

import json
import ast

k = '[1,2,3,4]'    #str

k1 = json.loads(k)
print(k1,type(k1))

k2 = ast.literal_eval(k)
print(k2,type(k2))

k3 = eval(k)
print(k3,type(k3))

# 结果
# [1, 2, 3, 4] 
# [1, 2, 3, 4] 
# [1, 2, 3, 4]