Question: I'm trying to delete a specific line that contains a specific string.

I've a file called **numbers.txt** with the following content:

> 
> peter  
> 
>  tom  
> 
>  tom1  
> 
>  yan  
> 
> 
> 
> 

What I want to delete is that **tom** from the file, so I made this function:

```
def deleteLine():
fn = 'numbers.txt'
f = open(fn)
output = []
for line in f:
    if not "tom" in line:
        output.append(line)
f.close()
f = open(fn, 'w')
f.writelines(output)
f.close()

```

The output is:

> 
> peter  
> 
>  yan  
> 
> 
> 
> 

As you can see, the problem is that the function delete **tom** and **tom1**, but I don't want to delete **tom1**. I want to delete just **tom**. This is the output that I want to have:

> 
> peter  
> 
>  tom1  
> 
>  yan  
> 
> 
> 
> 

Any ideas to change the function to make this correctly?

Answer: 
change the line:

```
    if not "tom" in line:

```

to:

```
    if "tom" != line.strip():

```
You can use regex.

```
import re
if not re.match("^tom$", line):
    output.append(line)

```

The `$` means the end of the string.