Python - example - (Stackoverflow)

# author: Bartlomiej "furas" Burek (https://blog.furas.pl)
# date: 2020.05.30
# https://stackoverflow.com/questions/62106026/how-to-use-string-variable-to-generate-name-of-the-lists-and-find-the-length-pyt

data = [
    [0,1,9,10],
    [2,3,11,12,13],
    [4,5,6,7,8],
    [16,17,25,26],
    [14,15,22,23]
]

#-------------------------------------

nn = 0
print('len', nn, ':', len(data[nn]) )

nn = 1
print('len', nn, ':', len(data[nn]) )

#-------------------------------------

print('--- loop ---')

total = 0
for item in data:
    print('len:',  len(item) )
    total += len(item)

print('total:', total)

#-------------------------------------

print('--- loop with enumerate ---')

total = 0
for number, item in enumerate(data):
    print('len', number, ':', len(item) )
    total += len(item)

print('total:', total)

#-------------------------------------

print('--- list comprehension ---')

total = sum(len(item) for item in data)
print('total:', total)

#-------------------------------------

print('--- single value ---')

print('value:', data[0][0])
print('value:', data[0][1])
print('value:', data[0][2])
print('value:', data[0][3])

#-------------------------------------

print('--- single value in loop ---')

for value in data[0]:
    print('value:', value)