解析后写入文件

Question

我已经编写了一个小python代码，它将读取一个示例csv文件并将其第一列复制到一个temp csv文件。现在，当我尝试将该临时文件与另一个文本文件进行比较，并尝试将结果写入另一个名为result file的文件时，该文件已创建，但内容为空。你知道吗

但当我测试了它在块，它是工作良好

import csv
f = open("sample.csv", "r")
reader = csv.reader(f)

data = open("temp1.csv", "w")
w = csv.writer(data)
for row in reader:
    my_row = []
    my_row.append(row[0])
    w.writerow(my_row)

with open('temp1.csv', 'r') as file1:
    with open('serialNumber.txt', 'r') as file2:
        same = set(file1).intersection(file2)

with open('result.txt', 'w') as file_out:
    for line in same:
        file_out.write(line)
        print line

你知道吗示例.csv你知道吗

M11435TDS144,STB#1,Router#1

M11543TH4292,STB#2,Router#1

M11509TD9937,STB#3,Router#1

M11543TH4258,STB#4,Router#1

你知道吗序列号.txt你知道吗

G1A114042400571

M11543TH4258

M11251TH1230

M11435TDS144

M11543TH4292

M11509TD9937

Answer 1

您应该先关闭输出文件（temp1.csv），然后才能从中读取数据。你知道吗

import csv
f = open("sample.csv", "r")
reader = csv.reader(f)

data = open("temp1.csv", "w")
w = csv.writer(data)
for row in reader:
    my_row = []
    my_row.append(row[0])
    w.writerow(my_row)
data.close()  # < - Should close it before reading it in the same program !!

with open('temp1.csv', 'r') as file1:
    with open('serialNumber.txt', 'r') as file2:
        same = set(file1).intersection(file2)

with open('result.txt', 'w') as file_out:
    for line in same:
        file_out.write(line)
        print line

Answer 2

有关代码的要点：

• data文件句柄未关闭。data.close()在写入temp1.csv之后。你知道吗
• 在代码same = set(file1).intersection(file2)中，直接将文件句柄file2传递给交集。它需要一个列表。这正是问题所在。应该是same = set(file1.readlines()).intersection(file2.readlines())

工作代码：

import csv
f = open("sample.csv", "r")
reader = csv.reader(f)

data = open("temp1.csv", "wb")
w = csv.writer(data)

for row in reader:
    my_row = []
    if len(row) != 0:
      my_row.append(row[0])
      w.writerow(my_row)
#File should be closed
data.close()

with open('temp1.csv', 'r') as file1:
    with open('serialNumber.txt', 'r') as file2:
      tmp_list = (file1.readlines())
      ser_list = (file2.readlines())
      same = set(file1.readlines()).intersection(file2.readlines())


with open('result.txt', 'w') as file_out:
    for line in same:
        file_out.write(line)

temp1.csv的内容：

M11435TDS144
M11543TH4292
M11509TD9937
M11543TH4258

内容结果.txt：

M11543TH4258
M11543TH4292
M11435TDS144

您可以使用with打开文件示例.csv和temp1.csv如下。

import csv

with open("sample.csv") as f:
  with open("temp1.csv",'wb') as data:
    reader = csv.reader(f)
    w = csv.writer(data)
    for row in reader:
      my_row = []
      my_row.append(row[0])
      w.writerow(my_row)


with open('temp1.csv', 'r') as file1:
    with open('serialNumber.txt', 'r') as file2:
      same = set(file1.readlines()).intersection(file2.readlines())

with open('result.txt', 'w') as file_out:
    for line in same:
        file_out.write(line)