有没有办法从 Python 中的文本文件中删除整个行的部分，然后删除其余部分的某些部分？

Question

I have a text file that looks like this:

                               Close
Datetime                            
2021-07-02 09:30:00-04:00  93.080002
2021-07-02 09:30:00-04:00  93.080002
2021-07-02 09:31:00-04:00  93.026001
2021-07-02 09:32:00-04:00  92.405403
2021-07-02 09:33:00-04:00  92.370003

I would like it to look like this:

93.080002
93.080002
93.026001
92.405403
92.370003

Is there a way to do this in Python by erasing the first 2 lines and then erasing only the times in the rest? Thanks in advance.

Answer 1

Given:

$cat ur_file
                               Close
Datetime                            
2021-07-02 09:30:00-04:00  93.080002
2021-07-02 09:30:00-04:00  93.080002
2021-07-02 09:31:00-04:00  93.026001
2021-07-02 09:32:00-04:00  92.405403
2021-07-02 09:33:00-04:00  92.370003

You can do:

with open(ur_file) as f_in:
    data=[line.strip().split()[-1] for i,line in enumerate(f_in) if i>1]

Result:

>>> data
['93.080002', '93.080002', '93.026001', '92.405403', '92.370003'] 

or:

>>> print('\n'.join(data)) 
93.080002
93.080002
93.026001
92.405403
92.370003

If you want a filter that writes the output to a file:

with open(ur_file) as f_in, open(out_file, 'w') as f_out:
    for i, line in enumerate(f_in):
        if i>1:
            f_out.write(f'{line.split()[-1]}\n')

Which results in an output file as desired.

Answer 2

using `test.txt as input file:

Close
Datetime                            
2021-07-02 09:30:00-04:00  93.080002
2021-07-02 09:30:00-04:00  93.080002
2021-07-02 09:31:00-04:00  93.026001
2021-07-02 09:32:00-04:00  92.405403
2021-07-02 09:33:00-04:00  92.370003

using code:

with open('test.txt' , 'r') as handle: #open test.txt file as handle, read mode and text mode (default)
    pippo = handle.readlines()         #reads the handle file all at once into lines

with open('res.txt' , 'w+') as whandle: #open res.txt file to write to it, write mode  and text mode (default)
    
    for i in range(0,len(pippo)):        # loops over the file lines from 0 to lenght of readlines alias number of lines 
        if i > 1:                        # starts at second line on (lines start at zero su skips line 0 and line 1
            print(pippo[i].split()[2])   # print line i splitted by whitespace third element: the number you are looking for 
            whandle.write(pippo[i].split()[2]+'\n') #writes the above lines adding \n line terminator to res.txt file

writes result as res.txt file:

93.080002
93.080002
93.026001
92.405403
92.370003