Python - 在包含字符串和数字的列表中订购数字值

Question

I have Created a list which contains all of the information from a scores file in python.

The scores .txt file:

Dan Danson,9,6,1
John Johnson,5,7,10
Mike Mikeson,10,7,6

I did this to get the information from the .txt file into a 2d list:

f = open(filename, 'r')
lines = f.readlines()
f.close()

scores = []
for line in lines: #Loads lines into a 2d list
    currentline = line.strip('\n').split(",")
    scores.append(currentline)

Now I have this list:

[['Dan Danson', '1', '6', '9'], ['John Johnson', '5', '7', '10'], ['Mike Mikeson', '10', '7', '6']]

From this list I would like to sort the numbers in the list so that they are ordered from highest to lowest so i get a list that looks like this:

[['Dan Danson', '9', '6', '1'], ['John Johnson', '10', '7', '5'], ['Mike Mikeson', '10', '7', '6']]

Finally I want to be able to print the list ordered highest to lowest.

Mike Mikeson,10,7,6
John Johnson,10,7,5
Dan Danson,9,6,1

Answer 1

Using sorted with int as a key function:

>>> rows = [
...     ['Dan Danson', '1', '6', '9'],
...     ['John Johnson', '5', '7', '10'],
...     ['Mike Mikeson', '10', '7', '6'],
... ]
>>>
>>> rows = [row[:1] + sorted(row[1:], key=int, reverse=True) for row in rows]
>>> sorted(rows, key=lambda row: sum(map(int, row[1:])), reverse=True)
[['Mike Mikeson', '10', '7', '6'],
 ['John Johnson', '10', '7', '5'],
 ['Dan Danson', '9', '6', '1']]

• sorted(row[1:], ..) : separate number values and sort.
• row[:1] : name as a list, alternatively you can use [row[0]] . Should be a list to be concatenated to a list of number strings.

Answer 2

Using sorted and map to cast strings to ints:

>>> l = [['Dan Danson', '9', '6', '1'], ['John Johnson', '10', '7', '5'], ['Mike Mikeson', '10', '7', '6']]
>>> for e in l:
...     print(e[0], *sorted(list(map(int, e[1:]))))
...     
... 
Dan Danson 1 6 9
John Johnson 5 7 10
Mike Mikeson 6 7 10

Answer 3

You can approach the problem this way as well. I first convert all grades into integer type so that I can keep my lambda function clean. I could have done the conversion in lambda function but it does not fancy me much.

You can see splitting the each problem into different module, gives re-usability.

test = [['Dan Danson', '1', '6', '9'], ["Karthikeyan", 10, 10, 10], ['John Johnson', '5', '7', '10'], ['Mike Mikeson', '10', '7', '6']]

def covert_to_integer(test):
    """
    Coverting all grades into integer type
    """
    for outer_index, item in enumerate(test):
        for inner_index, element in enumerate(item[1:], 1):
            test[outer_index][inner_index] = int(element)
    return sorting_by_sum(test)

def sorting_by_sum(test):
    """
    Sorting the records by sum of the grades. 
    """
    return sorted(test, key=lambda record: record[1]\
                                   + record[2] \
                                   + record[3], reverse=True)

if __name__ == "__main__":
    print covert_to_integer(test)

You can even use the sum method of list in lambda function. Like this:

return sorted(test, key=lambda record: sum(record[1:])\
                                   ,reverse=True)