How to append string in the middle of a pre-existing csv line?

Question

I am fairly new to working with python and finally encountered a problem I cannot circumvent. I will make this fairly simple.

I have a csv file with many lines that looks like this once I create a list variable:

['1t10000t11000tabcdeft1t+t10000t11000t"0,0,0"t1t1000t0n']

I want to add 2 new string variables after the final t0 before the n. Its important to indicate I still want the t before str1 and str2. So the output I desire should look like this:

['1t10000t11000tabcdeft1t+t10000t11000t"0,0,0"t1t1000t0tstr1tstr2n']

Thanks for your help!

str1 = hello
str2 = world
line = ['1t10000t11000tabcdeft1t+t10000t11000t"0,0,0"t1t1000t0n']
line.append(('t') + str1 + ('t') + str2)
print(line)

Current output:

['1t10000t11000tabcdeft1t+t10000t11000t"0,0,0"t1t1000t0n', 'tstr1tstr2']

Asked By: user20330606

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Source

Answer 1

append() is for adding an element to a list. To add to a string, use += on the variable that contains the string, which is line[0].

line[0] += f't{str1}t{str2}'

That said, it’s strange that you have the entire line as a single element of the list, rather than parsing the CSV row into a list of fields, using t as the field delimiter.

Answered By: Barmar

Answer 2

The append method adds the input to the list you use it on.
Since line is a list, you are getting a new entry into your list.

If you want to keep your string inside the list, you need to access the 0th index of the list to change the string:

line[0]

Once you have the string you need to separate it into two and add your new strings:

line[0] = line[0][:-2] + newinput + line[0][-2:]

Note the -2 separated because you want to separate the last two characters of your string: n

Answered By: Iddo Sadeh

How to append string in the middle of a pre-existing csv line?

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