Question

我有一个包含以下数据的.txt文件：

0,Rent1,Expense,16/02/2010,1,4000,4000  
0,Car Loan1,Expense,16/02/2010,2,4500,9000  
0,Flat Loan1,Expense,16/02/2010,2,4000,8000  
0,Rent2,Expense,16/02/2010,1,4000,4000  
0,Car Loan2,Expense,16/02/2010,2,4500,9000  
0,Flat Loan2,Expense,16/02/2010,2,4000,8000

现在我想用新项目替换第4行：

0，贷款，费用，19/02 / 2010,2,5000,10000

我使用以下代码：

newline='0,Loan,Expense,19/02/2010,2,5000,10000'
lnum=1
for line in fileinput.FileInput("sample.txt",inplace=1):
    if lnum=='4':
        result = newline
        lnum=lnum+1
    else:
        result=line
        lnum=lnum+1
    sys.stdout.write(result)

但它显示的文件如下：

0,Rent1,Expense,16/02/2010,1,4000,4000  
0,Car Loan1,Expense,16/02/2010,2,4500,9000  
0,Flat Loan1,Expense,16/02/2010,2,4000,8000  
0,Loan,Expense,19/02/2010,2,5000,100000,Car Loan2,Expense,16/02/2010,2,4500,9000
0,Flat Loan2,Expense,16/02/2010,2,4000,8000

我该如何解决这个问题？

Answer 1

添加新行

newline='0,Loan,Expense,19/02/2010,2,5000,10000'
lnum=1
for line in fileinput.FileInput("sample.txt",inplace=1):
    if lnum==4:
        result = newline+"\n"
    else:
        result=line
    lnum=lnum+1    
    sys.stdout.write(result)

或者您可以将newline变量声明为

newline="0,Loan,Expense,19/02/2010,2,5000,10000\n"

Answer 2

使用枚举：减少代码减少错误的可能性

newline = '0,Loan,Expense,19/02/2010,2,5000,10000\n'
for lnum, line in enumerate(fileinput.FileInput("sample.txt",inplace=1)):
    if lnum == 4:
        line = newline
sys.stdout.write(line)

Answer 3

sys.stdout.write()不会添加换行符。添加\n，之后使用print或使用print的文件语法：

print >>sys.stdout, result

...或者因为sys.stdout是默认值：

print result

Answer 4

替换：

result = newline #you lose the newline here

使用：

result = newline + '\n' #or '\r\n' depending on your newline format.

替换文件中的整行

4 个答案: