在python中对文本文件执行多次写入操作

Question

I am trying to clean up a text file to a desired format. To achieve this i am currently opening the file, performing a certain operation and closing it.I am repeating the same for few other operations. Is there a better way of doing this. The operations that i want to perform are

1. Open the text file and replace a certain string with a new string
2. Delete all the above string upto the new strings
3. Remove any tabs in the text file
4. Replace all blank spaces with a comma

Furthermore,i am writing the output to a new file every time. Can i do all these in the same file while all performing the formatting operations?

Text file sample

ANX ANV 91 BB
cc yy the 12
okr out 1 11 


temp1   temp2(a/b)      temp3(t)  temp4(x)
0   11  9a   1.1
1   22  9b   12
2   33  9c   4
3   44  9d   92

Expected:

temp1,temp2,temp3,temp4
0,11,9a,1.1
1,22,9b,12
2,33,9c,4
3,44,9d,92

My code

OldString = "temp1   temp2(a/b)      temp3(t)  temp4(x)"
NewString = "temp1 temp2 temp3 temp4"


def myfunction():    
    inputFile = open("Temp1.txt",encoding="utf8")
    exportFile = open('File1.txt','w',encoding="utf8")

    with inputFile as f:
        #Repalce old string by NewString
        newText=f.read().replace(OldString,NewString)
    
    with exportFile as f:
        f.write(newText)
        
    lines_to_write = []
    tag_found = False
 
    #Delete all extra strings upto the NewString.
    #Also remove any tabs
    with open('File1.txt',encoding="utf8") as in_file:
        for line in in_file:
            if line.strip() == NewString:
                tag_found = True
            if tag_found:
                lines_to_write.append(line.replace('\t', ' '))

    with open('File2.txt','w',encoding="utf8") as out_file:
        out_file.writelines(lines_to_write)

    lines_to_write = []
    tag_found = False

    #Replace all blank spaces with comma
    with open('File2.txt',encoding="utf8") as in_file:
        for line in in_file:
            if line.strip() == NewString:
                tag_found = True
            if tag_found:
                lines_to_write.append(line.replace(' ', ','))
        
        with open('File3.txt','w',encoding="utf8") as out_file:
            out_file.writelines(lines_to_write)

Thank you

Answer 1

I've wrote a little function to do what you want. It starts by looking the first line you want to append in the new file. Then it format and append to an array only the lines coming after this one. Then it create a file writing this new array.

# Get index of first string to insert
def get_index(file, string):
    for line in file:
        if string in line:
            return file.index(line)


# Main function to write files
def write_files(in_file, out_file, old_string, new_string):

    # Opens input file, loads to a list then close
    with open(in_file, 'r', encoding="utf8") as input_file:
        old_file = input_file.readlines()

    # Discover index of old string you want to replace
    new_string_index = get_index(old_file, old_string)

    # Crates array with your new string formatted
    lines_to_write = [','.join(new_string.split())]

    # Populate lines_to_write array with lines formatted from the index you want
    for old_line in old_file[new_string_index + 1:]:
        new_line = old_line.strip().split()
        lines_to_write.append(','.join(new_line))

    # Write lines_to_write array to output file
    with open(out_file, 'w', encoding="utf8") as export_file:
        for line in lines_to_write:
            export_file.write(line)
            export_file.write('\n')


# Call function with your variables
if __name__ == "__main__":
    OldString = "temp1   temp2(a/b)      temp3(t)  temp4(x)"
    NewString = "temp1 temp2 temp3 temp4"
    inputFile = "Temp1.txt"
    exportFile = 'File1.txt'
    write_files(inputFile, exportFile, OldString, NewString)