Question

我有一个很大的CSV文件，其中行的长度各不相同：

215080,49,3,0.0,22,42,0.0
215082,49,3,0.0,22,43,59.999 
215083,49,3,0.0,22,45,0.0
215085,49,3,0.0,22,46,59.999
215086,49,3,0.0,22,48,0.0
215087,49,3,0.0,22,49,0.001
215088,49,3,0.0,22,49,59.999
215089,49,3,0.0,22,51,0.0
215090,49,3,0.0,22,52,0.001
215688,49,1,59.999,22,49,0.001
215689,49,1,59.999,22,49,59.999
215690,49,1,59.999,22,51,0.0
215691,49,1,59.999,22,52,0.001
216291,49,1,0.001,22,51,0.0
216292,49,1,0.001,22,52,0.001
216293,49,1,0.001,22,52,59.999

例如，我想用分号（,）替换每行中的第四个逗号（;）。我怎样才能最有效地做到这一点？

Answer 1

import csv
with open('source.csv','rb') as source:
    rdr= csv.reader( source )
    with open('revised.csv','wb') as target:
        wtr= csv.writer( target )
        for r in rdr:
            wtr.writerow( (r[0], r[1], r[2], '{0};{1}'.format(r[3],r[4]), r[5], r[6]) )

Answer 2

你可以在每一行输入上做这样的事情。

tmp = line.split(',', 4)
newline = '%s;%s' % (','.join(tmp[:4]), tmp[4])

Answer 3

另一种方法

>>> a = '215080,49,3,0.0,22,42,0.0'
>>> b = a.split(',')
>>> ','.join(b[0:3] + [b[3] + ';'  + b[4]] + b[5:])
'215080,49,3,0.0;22,42,0.0'

如何使用Python替换CSV文件中的特定逗号？

3 个答案: