Python String to Array conversion

Question

My requirement is to take 'arrList' string as an argument from main and split it using comma (,) and each name is an Array (arr1, arr2, arr3). Now all 3 arrays should be appended to a list. The output should be : list: 1,2,3,7,8,9,11,22,33. But should follow below steps only while implementing. Tried below code, but not able to convert. Any help is appreciated.

arr1 = [1,2,3]
arr2 = [7,8,9]
arr3 = [11,22,33]
list = []

def arrTest(arrList):
        var = arrList.split(',')
        for x in var:

    #f = open(, "r")
        #for x in f:
        #   list.append(x.rstrip('\n'))


if __name__ == '__main__':
    arrList = "arr1,arr2,arr3"
    arrTest(arrList)

Answer 1

arr1 = [1,2,3]
arr2 = [7,8,9]
arr3 = [11,22,33]
the_list = []

arrList = "arr1,arr2,arr3"
for array in arrList.split(','):
    if array in locals():
        the_list.extend(locals()[array])

print (the_list)

Output

[1, 2, 3, 7, 8, 9, 11, 22, 33]

locals() function returns a dictionary containing the variables defined in the local namespace.

Answer 2

You can use python dict data structure.

arr1 = [1,2,3]
arr2 = [7,8,9]
arr3 = [11,22,33]
d = {"arr1": arr1, "arr2": arr2, "arr3": arr3}

def arrTest(arrList):
    l = []
    var = arrList.split(',')
    for x in var:
        for e in d[x]:
            l.append(e)
    return l

if __name__ == '__main__':
    arrList = "arr1,arr2,arr3"
    l = arrTest(arrList)
    print(l)

Output

[1, 2, 3, 7, 8, 9, 11, 22, 33]

Answer 3

Use eval function

arr1 = [1,2,3]
arr2 = [7,8,9]
arr3 = [11,22,33]
out = []

def arrTest(arrList):
        list_strs = arrList.split(',')
        for list_str in list_strs:
          l = eval(list_str)
          out.extend(l)


arrList = "arr1,arr2,arr3"
arrTest(arrList)
print(out)

[1, 2, 3, 7, 8, 9, 11, 22, 33]