Treating the nested list but error: could not convert string into float

Question

This is my code:

units_list = [['CITS1001', '95'], ['CITS1401', '100'], ['CITS1402', '97'], ['CITS2002', '99'], ['CITS2211', '94'], ['CITS2401', '95'], ['CITS3001', '93'], ['CITS3002', '93'], ['CITS3003', '91'], ['CITS3200', '87'], ['CITS3401', '98'], ['CITS3402', '93'], ['CITS3403', '88']]
students_list = [['Needie Seagoon', '57', '', '83', '55', '78', '', '91', '73', '65', '56', '', '', ''], ['Eccles', '', '98', '91', '80', '', '66', '', '', '', '77', '78', '48', '77'], ['Bluebottle', '61', '', '88', '80', '60', '', '45', '52', '91', '85', '', '', ''], ['Henry Crun', '92', '', '58', '50', '57', '', '67', '45', '77', '72', '', '', ''], ['Minnie Bannister', '51', '', '97', '52', '53', '', '68', '58', '70', '69', '', '', ''], ['Hercules Grytpype-Thynne', '', '78', '62', '75', '', '67', '', '', '', '48', '56', '89', '67'], ['Count Jim Moriarty', '51', '', '68', '51', '66', '', '55', '72', '50', '74', '', '', ''], ['Major Dennis Bloodnok', '', '54', '47', '59', '', '48', '', '', '', '66', '58', '53', '83']]

normalised = [[students_list[0]] +
[None if students_list is ''
else
## convert number string to float to count
float(studentScores) / float(units_list[index][1])
for index, studentScores in enumerate(students[1:])
] for students in students_list]

print(normalised)

and there is an error in this line:

for index, studentScores in enumerate(students[1:])

What should I change and what caused this problem?

The error in on the previous line.

ForceBru
– ForceBru

2018-09-14 15:49:29 +00:00
Commented Sep 14, 2018 at 15:49 — ForceBru
– ForceBru, Commented Sep 14, 2018 at 15:49

Patrick Haugh · Accepted Answer · 2018-09-14 15:49:08Z

1

Your expression

None if students_list is '' else float(studentScores)/float(units_list[index][1])

should probably be

None if studentScores is '' else float(studentScores)/float(units_list[index][1])

answered Sep 14, 2018 at 15:49

Patrick Haugh

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Comments

Yiling Liu · Accepted Answer · 2018-09-14 16:36:04Z

The correct expression:

normalised=[[students[0]]+
[None if studentScores is ''
else
## convert number string to float to count
float(studentScores)/float(units_list[index][1])
for index, studentScores in enumerate(students[1:])
]for students in students_list]
print(normalised)

I found that the first line is also incorrect

and now, we can get a correct output:

[['Needie Seagoon', 0.6, None, 0.8556701030927835, 0.5555555555555556, 0.8297872340425532, None, 0.978494623655914, 0.7849462365591398, 0.7142857142857143, 0.6436781609195402, None, None, None], ['Eccles', None, 0.98, 0.9381443298969072, 0.8080808080808081, None, 0.6947368421052632, None, None, None, 0.8850574712643678, 0.7959183673469388, 0.5161290322580645, 0.875], ['Bluebottle', 0.6421052631578947, None, 0.9072164948453608, 0.8080808080808081, 0.6382978723404256, None, 0.4838709677419355, 0.5591397849462365, 1.0, 0.9770114942528736, None, None, None], ['Henry Crun', 0.968421052631579, None, 0.5979381443298969, 0.5050505050505051, 0.6063829787234043, None, 0.7204301075268817, 0.4838709677419355, 0.8461538461538461, 0.8275862068965517, None, None, None], ['Minnie Bannister', 0.5368421052631579, None, 1.0, 0.5252525252525253, 0.5638297872340425, None, 0.7311827956989247, 0.6236559139784946, 0.7692307692307693, 0.7931034482758621, None, None, None], ['Hercules Grytpype-Thynne', None, 0.78, 0.6391752577319587, 0.7575757575757576, None, 0.7052631578947368, None, None, None, 0.5517241379310345, 0.5714285714285714, 0.956989247311828, 0.7613636363636364], ['Count Jim Moriarty', 0.5368421052631579, None, 0.7010309278350515, 0.5151515151515151, 0.7021276595744681, None, 0.5913978494623656, 0.7741935483870968, 0.5494505494505495, 0.8505747126436781, None, None, None], ['Major Dennis Bloodnok', None, 0.54, 0.4845360824742268, 0.5959595959595959, None, 0.5052631578947369, None, None, None, 0.7586206896551724, 0.5918367346938775, 0.5698924731182796, 0.9431818181818182]]

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