I have a string read from a file that contains a data and the newline special character '\ n'. Example:
dado = 'teste \n'
First check the string size, so I can remove the last two characters, but how can I remove pointing to the character's specific position?
Strings in Python, as in many other languages, are not changeable: that is, for any modification, you must create a new string (in general it is ok to associate the new string with the same variable).
Now the Python slice syntax is extremely convenient for trimming, and pasting strings - just keep in mind that, as if it were a rule, the first index of the slice, before the ":" is inclusive, and the end is unique - this allows for very practical things like:
dado = dado [0:4] + dado[4:]
Preserves the same string without duplicating any letters. (Cut from start to position 4 - 0 could be omitted and then cut from position 4 to the end - the omitted end lets you not know the full size of the string)
So, to cut the letter of the position [4] (in this case, the second "e"), you can write:
dado = dado[0:3] + dado[4:]
The syntax of indexes and slices also allows negative indexes - which count from the end of the string. So empty is the end of the string, "-1" is the address of the last character, "-2" of the penultimate, and so on.
To cut the last two characters, just do:
dado = dado[:-2]
(cut from the beginning to the position of the penultimate character)
You will hardly have a case like this where you need to explicitly place the string size (returned by len(dado) ) - and this avoids a lot of code that - in the head of people is "straight", but typing, and looking in the code would be much more tiring than simply using negative indexes.
To do this, you can use slices .
In your case, it would look like this:
dado = dado[:5] # Pega do começo até a posição 5 - 1
Remembering that strings are immutable a>, so you can not remove a character: What you can actually do is re-assign a copy of string to your variable without the unwanted characters.