How can I use %s to replace text within a file in python?

Question

I've been working on a project where I open and read a file and replace its text with input, this is what I have been trying to do to put certain words in,

for i in range(0, length):
    finallib = str(picks[choice]) % (picked[i])

where length is the length - 1 of the list 'picked' and picked is a list of words. 'picks[choice]' is the selection of text from the file that the user chooses to put new words into. Within the file, The text goes like this 'file text file text file text %s file text file text file text', and I get the error that there are not enough arguments for format string. How can I get it to replace what I want it to?

P.S. the substitution doesn't go into another file or the same file, it is put into a variable that is displayed after it is calculated.

lbragile · Accepted Answer · 2019-12-04 02:21:23Z

2

Why not just use format()?

for i in range(length): # range automatically starts at 0
    finallib = '{} % {}'.format(picks[choice],picked[i])

Or cleaner (list comprehension):

finallib = ['{} % {}'.format(picks[choice],picked[i]) for i in range(length)]

answered Dec 4, 2019 at 2:21

lbragile

8,1703 gold badges38 silver badges73 bronze badges

Sign up to request clarification or add additional context in comments.

8 Comments

Ben Over a year ago

so I tried that exact phrasing and it returned the file choice without substitutions included, right now the spots reserved for inputs are marked with '%s', should they be marked with something else or is the code missing that piece somewhere? When I tried the second option it printed the file selection multiple times.

lbragile Over a year ago

'{ }".format(x) places the variable x in the { } inside the string (formed by the quotes). If you have many variables just use { } where ever they need to go. In the above example there are 2 variables and each is placed around the % symbol in the string at the order they are written in the format(). But what you said should also work - namely, using %s. Without seeing the rest of the code there is not much I can suggest.

Ben Over a year ago

so I tried to replace %s with {} and I tried to just use %s where you had {} in the example, when using the first method output was only '%s % %s' and when I tried the second it output the file selection followed by % {}. I do not understand this premise very well

lbragile Over a year ago

Read about format() online: geeksforgeeks.org/python-format-function

Ben Over a year ago

I have read the article, and I now don't think its the command screwing it but the way it gets where it's going. the way I get the string is by access from a file, and I think that that is screwing up the way that it reads either %s or {}. The error I am now getting is 'tuple range out of index' or something like that, and from what I know thats what happens when there aren't enough arguments. I know I have the right amount of arguments but can't get it to replace each sub with an element in the list. I believe it wants to replace the first sub with the entire list. how do I overcome this?

|

Collectives™ on Stack Overflow

How can I use %s to replace text within a file in python?

1 Answer 1

8 Comments

Your Answer

Hot Network Questions

Collectives™ on Stack Overflow

1 Answer 1

8 Comments

Your Answer

Sign up or log in

Post as a guest

Related