在Python中以不同的顺序写出CSV列

问题描述

| 我意识到这与这个问题非常相似。但是，我有一个CSV文件，该文件的格式总是与我需要用不同顺序写出的列相同，以便将其向下移动到数据处理管道中。如果我的csv文件包含标题和数据，如下所示：

Date,Individual,Plate,Sample,test,QC
03312011,Indiv098,P342,A1,deep,passed
03312011,Indiv113,P352,C3,passed

如何写出与原始输入csv具有相同列但按以下顺序排列的csv文件：

test,QC,Sample
deep,passed,A1
deep,C3

我最初的想法是做这样的事情：

f = open(\'test.csv\')
lines = f.readlines()
for l in lines:
    h = l.split(\",\")
    a,b,c,d,e,f  = h
    for line in h:
        print e,f,

    

解决方法

如果几乎没有机会每次输入文件或输出文件都具有相同的布局，那么这是一种更通用的获取“ reorderfunc”的方法：

writenames = \"test,QC,Plate,Sample\".split(\",\") # example
reader = csv.reader(input_file_handle)
writer = csv.writer(output_file_handle)
# don\'t forget to open both files in binary mode (2.x)
# or with `newline=\'\'` (3.x)
readnames = reader.next()
name2index = dict((name,index) for index,name in enumerate(readnames))
writeindices = [name2index[name] for name in writenames]
reorderfunc = operator.itemgetter(*writeindices)
writer.writerow(writenames)
for row in reader:
    writer.writerow(reorderfunc(row))

    ,

reorderfunc = operator.itemgetter(4,5,2,3)

 ...

newrow = reorderfunc(oldrow)
 ...

    ,输入为

src.csv

：

import csv

with open(\'x.csv\',\'rb\') as i:
    with open(\'y.csv\',\'wb\') as o:
        r = csv.DictReader(i)
        w = csv.DictWriter(o,\'test QC Plate Sample\'.split(),extrasaction=\'ignore\')
        w.writeheader()
        for a in r:
            w.writerow(a)

输出量

test,Sample
deep,passed,P342,A1
deep,P352,C3

    ,

#Use CSV library
import csv
media = {}
files=[\'Online.txt\']
directory = \"C:/directory/\"
rowCnt=0

for file in files:

    file=directory+file

    with open(file,\'rb\') as f:
        reader = csv.reader(f,delimiter=\'|\') #use pipe delimiter

        for row in reader:
            rowCnt+=1
            if (rowCnt % 1000) == 0:
                print (\'\"%s\",\"%s\",\"%s\"\')% (row[1],row[4],row[14],row[17],row[18],row[24],row[25],row[28],row[30])