问在python中将行转置为列

EN

import pandas
from io import StringIO # python 3
# from StringIO import StringIO # python 2

datafile = StringIO("""\
Country;Class;Number
UK;1;50
Germany;2;30
France;3;50
France;1;20
""")
df = pandas.read_csv(datafile, sep=';')
print(df.pivot(index='Country', columns='Class', values='Number'))

Class     1   2   3
Country            
France   20 NaN  50
Germany NaN  30 NaN
UK       50 NaN NaN

import csv

with open('test.csv', 'r') as f:
    reader = csv.DictReader(f, delimiter=';')
    # make a dict of empty lists, to contain our values
    transposed = {k:[] for k in reader.fieldnames}  # could use defaultdict here
    for row in reader:
        for k, v in row.items():
            transposed[k].append(v)
print(transposed)

{
    'Country': ['UK', 'Germany', 'France', 'France'],
    'Class': ['1', '2', '3', '1'],
    'Number': ['50', '30', '50', '20']
}

from collections import defaultdict
transposed = defaultdict(list)