Question

我有两个CSV文件，每个文件有6列，并且都有一个公用列{{1}}（用于比较的主键）。例如，EmpID是：

File1.csv

EmpID1,Name1,Email1,City1,Phone1,Hobby1 120034,Tom Hanks,tom.hanks@gmail.com,Mumbai,8888999,Fishing是

File2.csv

需要比较文件中的差异，并且只应将不同的行和列添加为新的输出文件，

EmpID2,Name2,Email2,City2,Phone2,Hobby2
120034,Tom Hanks,hanks.tom@gmail.com,Mumbai,8888999,Running

目前，我已经用Python编写了以下代码。现在我想知道如何识别和选择差异。任何指示和帮助将不胜感激。

EmpID1,Email1,Email2,Hobby1,Hobby2
120034,tom.hanks@gmail.com,hanks.tom@gmail.com,Fishing,Running

Answer 1

首先将文件读取为dict结构，并以“ EMPID”为键指向整个行：

import csv
fieldnames = [] # to store all fieldnames
with open('File1.csv') as f:
    cf = csv.DictReader(f, delimiter=',')
    data1 = {row['EMPID1']: row for row in cf}
    fieldnames.extend(cf.fieldnames)

with open('File2.csv') as f:
    cf = csv.DictReader(f, delimiter=',')
    data2 = {row['EMPID2']: row for row in cf}
    fieldnames.extend(cf.fieldnames)

然后标识两个字典中的所有ID：

ids_to_check = set(data1) & set(data2)

最后，遍历id并比较行本身

with open('OutputFile.csv', 'w') as f:
    cw = csv.DictWriter(f, fieldnames, delimiter=',')
    cw.writeheader()
    for id in ids_to_check:
        diff = compare_dict(data1[id], data2[id], fieldnames)
        if diff:
            cw.writerow(diff)

这是compare_dict函数的实现：

def compare_dict(d1, d2, fields_compare):
    fields_compare = set(field.rstrip('12') for field in fields_compare)
    if any(d1[k + '1'] != d2[k + '2'] for k in fields_compare):
        # they differ, return a new dict with all fields
        result = d1.copy()
        result.update(d2)
        return result
    else:
        return {}

比较两个CSV文件，仅输出具有不同的特定列的行

1 个答案: