Question

我有一个如下所示的csv，需要根据第3列中的值将csv解析为多行，以加载到db ...

由于限制，我只能使用import csv模块来执行此功能，这就是我遇到的问题，我面临的问题是，如果我写了一个插入查询...它没有取出所有的rows ..它只获取每个for循环中的最后一条记录并插入表

1,2,3,4,5
10,20,30,50
100,200,300,400

可能的代码：

if column 3 = 'y' else 'n' in column 4 in table

输出：

1,2,3,y
1,2,4,n
1,2,5,n
10,20,30,y
10,20,50,n
100,200,300,y
100,200,400,n

这是我的代码

import csv

import os

#Test-new to clean.csv
fRead=open("clean.csv")
csv_r=csv.reader(fRead)
#to skip first two lines
leave=0
for record in csv_r:
    if leave<2:
        leave+=1
        continue
    #storing the values of column 3,4,5 as an array
    JMU=[]

    for t in [2, 3, 4]:
        if not(record[t] in ["", "NA"]):
            JMU.append(record[t].strip())
            #print len(JMU)
            #print "2"
    if len(JMU)==0:
        #print "0"
        pass
    else:

#check if the name contains WRK
        isWRK1 = "Table"
        for data in JMU:
            print data
            if data[:3].lower()=="wrk" or data[-3:].lower()=="wrk":
                isWRK1="Work"
                print isWRK
            else:
                isWRK = "table"
        #check if column 2 value is "Yes" or "No"       
        fourthColumn="N"
        if not(record[2] in ["", "NA"]):
            #print record[2]
            if record[3].strip().lower()=="no":
              #  print record[3]
                fourthColumn = "I"
            else:
                fourthColumn = "N"

        for i in JMU:
            iWRK = "Table"
            if record[2]==i:
                newRecord = [record[0], record[1], i, fourthColumn, isWRK,]
                #print newRecord
            elif record[3] == i:


                newRecord = [record[0], record[1], i, "N", isWRK]
                #print newRecord
            else:

                newRecord = [record[0], record[1], i, "N", isWRK]
        print ("insert into table (column_a,column_b,column_c,column_d,column_e) values (%s,%s,%s,%s,%s)"% (record[0],record[1],record[2],record[3],record[4]))



fRead.close()
fWrite.close()

Answer 1

我假设您希望将前2列保持为常量，并为同一输入行上的每个下一个数字创建一个新行。

最初我想出了这个1-liner awk命令：

$ cat data 
1,2,3,4,5
10,20,30,50
100,200,300,400
$ awk -F, -v OFS=, '{for(i=3;i<=NF;i++) print $1, $2, $i, (i==3?"y":"n")}' data 
1,2,3,y
1,2,4,n
1,2,5,n
10,20,30,y
10,20,50,n
100,200,300,y
100,200,400,n

然后我使用csv模块将其复制到python中：

import csv
with open('data', 'r') as f:
    reader=csv.reader(f)
    for row in reader:
        l=list(map(int, row))
        for i in range(2, len(l)):
            print(l[0], l[1], l[i], 'y' if i==2 else 'n', sep=',')

这是一个与awk输出相同的示例运行：

1,2,3,y
1,2,4,n
1,2,5,n
10,20,30,y
10,20,50,n
100,200,300,y
100,200,400,n

根据列值在csv中将行拆分为多行

1 个答案: