Making two columns by skipping a string in Python?-CodePudding

For example, let's say I have a file called test.txt, the content is as follows, thousands of strings under each other.

I will come one day.
What did you do.
I will go home.
OK, I'll come too.
I'm waiting then.
I will come.

What I want is that the first two lines are written side by side. When they are written side by side, put the special character I want between them. So like this

I will come one day. ■What did you do?
I'll go home. ■Okay, I'll come too.
I'm waiting then. ■I'll come.

I need a code so that I can print them like this. I've been searching for exactly four hours, but I finally gave up and I'm going to sleep. Thanks everyone in advance.

CodePudding user response：

If your input line count is even, or it's fine if last one got lost with odd number of lines, try this:

>>> with open("src.txt") as src, open("output.txt", "wt") as output:
...     while (line1 := src.readline()) and (line2 := src.readline()):
...         output.write(f"{line1.strip()} # {line2.strip()}\n")

src.txt:

I will comeone day.
What did you do.
I will go home.
OK, I'll come too.
I'm waiting then.
I will come.

output.txt:

I will comeone day. # What did you do.
I will go home. # OK, I'll come too.
I'm waiting then. # I will come.

Or if you need it to work with odd number too, try this:

>>> with open("src.txt") as src, open("output.txt", "wt") as output:
...     while (line1 := src.readline()) and (line2 := src.readline()):
...         output.write(f"{line1.strip()} # {line2.strip()}\n")
...     if line1 and not line2:
...         output.write(line1)

src.txt:

I will comeone day.
What did you do.
I will go home.
OK, I'll come too.
I'm waiting then.
I will come.
Meow

output.txt:

I will comeone day. # What did you do.
I will go home. # OK, I'll come too.
I'm waiting then. # I will come.
Meow

This second one will throw error when there's only one line in text file, but since you said thousands, should be fine.

CodePudding user response：

Prints all lines in the file with the special character in between

special_char = "#"

with open("text.txt", "r") as txt:
    lines = txt.readlines() # read all lines in the file

lines = [line.strip("\n") for line in lines] # remove newline charactor from its end
n = len(lines) #find the number of lines

if n%2 == 0:  # if number of lines is even
    for i in range(0,n,2):  # go from 0 to n with 2 steps at a time, i.e, i = i 2
        print(f"{lines[i]} {special_char} {lines[i 1]}")

else:  # if number of lines is odd
    for i in range(0,n-1,2):
        print(f"{lines[i]} {special_char} {lines[i 1]}")
    print(lines[-1])  # print the last line in the list

Output:

Even number of lines

I will come one day. # What did you do.
I will go home. # OK, I'll come too.
I'm waiting then. # I will come.

Odd number of lines

I will come one day. # What did you do.
I will go home. # OK, I'll come too.
I'm waiting then. # I will come.
See you then