Python-替换CSV文件中的行的值
我有以下数据集:Python-替换CSV文件中的行的值,python,csv,Python,Csv,我有以下数据集: ['XXXX-XXXX', '0'] ['XXXX-XXXX', '0'] ['XXXX-XXXX', '0'] ['XXXX-XXXX', '0'] ['XXXX-XXXX', '0'] ['XXXX-XXXX', '0'] ['XXXX-XXXX', '0'] ['XXXX-XXXX', '0'] 基本上,我希望在每次运行程序后,以增量方式将第二个字段“0”更改为“1”,如下所示: ['XXXX-XXXX', '1'] # first run ['XXXX-XXXX',
['XXXX-XXXX', '0']
['XXXX-XXXX', '0']
['XXXX-XXXX', '0']
['XXXX-XXXX', '0']
['XXXX-XXXX', '0']
['XXXX-XXXX', '0']
['XXXX-XXXX', '0']
['XXXX-XXXX', '0']
基本上,我希望在每次运行程序后,以增量方式将第二个字段“0”更改为“1”,如下所示:
['XXXX-XXXX', '1'] # first run
['XXXX-XXXX', '0']
['XXXX-XXXX', '0']
['XXXX-XXXX', '0']
['XXXX-XXXX', '0']
['XXXX-XXXX', '0']
['XXXX-XXXX', '0']
['XXXX-XXXX', '0']
['XXXX-XXXX', '1'] # second run
['XXXX-XXXX', '1']
['XXXX-XXXX', '0']
['XXXX-XXXX', '0']
['XXXX-XXXX', '0']
['XXXX-XXXX', '0']
['XXXX-XXXX', '0']
['XXXX-XXXX', '0']
['XXXX-XXXX', '1'] # eigth run
['XXXX-XXXX', '1']
['XXXX-XXXX', '1']
['XXXX-XXXX', '1']
['XXXX-XXXX', '1']
['XXXX-XXXX', '1']
['XXXX-XXXX', '1']
['XXXX-XXXX', '1']
应直接编辑.csv文件。我根本不知道如何解决这个问题,我是一个python新手。这里有一些东西可以让您朝着正确的方向前进
with open('path/to/filename') as filehandler_name:
# this is how you open a file for reading
with open('path/to/filename', 'w') as filehandler_name:
# this is how you open a file for (over)writing
# note the 'w' argument to the open built-in
import csv
# this is the module that handles csv files
reader = csv.reader(filehandler_name)
# this is how you create a csv.reader object
writer = csv.writer(filehandler_name)
# this is how you create a csv.writer object
for line in reader:
# this is how you read a csv.reader object line by line
# each line is effectively a list of the fields in that line
# of the file.
# # XXXX-XXXX, 0 --> ['XXXX-XXXX', '0']
对于小文件,可以执行以下操作:
import csv
with open('path/to/filename') as inf:
reader = csv.reader(inf.readlines())
with open('path/to/filename', 'w') as outf:
writer = csv.writer(outf)
for line in reader:
if line[1] == '0':
writer.writerow([line[0], '1')
break
else:
writer.writerow(line)
writer.writerows(reader)
import csv, os
with open('path/to/filename') as inf, open('path/to/filename_temp', 'w') as outf:
reader = csv.reader(inf)
writer = csv.writer(outf)
for line in reader:
if line[1] == '0':
...
... # as above
os.remove('path/to/filename')
os.rename('path/to/filename_temp', 'path/to/filename')
对于inf.readlines
将终止内存分配的大型文件,因为它会立即将整个文件拉入内存,您应该执行以下操作:
import csv
with open('path/to/filename') as inf:
reader = csv.reader(inf.readlines())
with open('path/to/filename', 'w') as outf:
writer = csv.writer(outf)
for line in reader:
if line[1] == '0':
writer.writerow([line[0], '1')
break
else:
writer.writerow(line)
writer.writerows(reader)
import csv, os
with open('path/to/filename') as inf, open('path/to/filename_temp', 'w') as outf:
reader = csv.reader(inf)
writer = csv.writer(outf)
for line in reader:
if line[1] == '0':
...
... # as above
os.remove('path/to/filename')
os.rename('path/to/filename_temp', 'path/to/filename')
找到第一个0,更改为1,然后只写其余的行。如果您根本不知道如何处理问题,那么您在此处询问时没有正确使用堆栈溢出。这是为你在中途遇到问题而准备的。你才刚刚开始,这可能会对你有所帮助