CODEWITHSUNDEEP
pythonstringinteger
John Smith
John Smith

Reputation: 1

python 3 - find and replace all numbers in a text file

I realise that finding and replacing in a text file has already been asked, but I wasn't sure how to apply it to my situation.

Basically, this goes on earlier in the program:

while True:
    ingredient = input("what is the name of the ingredient? ")
    if ingredient == "finished":
        break
    quant = input("what is the quantity of the ingredient? "))
    unit = input("what  is the unit for the quantity? ")
    f = open(name+".txt", "a")
    f.write("\ningredient: "+ingredient+quant+unit)

Later on, I need to read the text file. However, I need to replace the numbers (quant) with the number times a different number that's inputted by the user. At the moment I have this, but I know it's all wrong.

file2 = open(recipe+".txt", "r")
file3 = open(recipe+".txt.tmp", "w")
for line in file2:
 file3.write(line.replace(numbers,numbers * serve))
print(file3)
os.remove(recipe+".txt.tmp")

the line.replace part is currently psuedocode as I'm not sure what to put there... Sorry if it's a noobie question, but I'm really stuck on this. Thanks for listening!

me.

Upvotes: 0

Views: 2379

Answers (2)

ASGM
ASGM

Reputation: 11381

When you're writing the file, do yourself a favor and put some kind of delimiter between the different entries:

f.write("\t".join(["\ningredient: ", ingredient, quant, unit]))

Then when you open the file again, you can just split the string of each line using that delimiter and operate on the third entry (which is where the number from quant will be):

lines = file2.readlines()
for line in lines[1:]: # To skip the first empty line in the file
    line = line.split("\t")
    line[2] = str(float(line[2]) * int(serve))
    file3.write("\t".join(line))

N.B. There are better ways to store python data (like pickles or CSV), but this should work with your current implementation without much modififcation.

Upvotes: 2

Abhijit
Abhijit

Reputation: 1

You could try something like this : 

    from tempfile import mkstemp
    from shutil import move
    from os import remove, close

    def replace(file_path, pattern, subst):
     #Create temp file
    fh, abs_path = mkstemp()
    old_file = open(file_path)
     for line in old_file:
     new_file.write(line.replace(pattern, subst))
     #close temp file
     new_file.close()
     close(fh)
     old_file.close()
     #Remove original file
     remove(file_path)
      #Move new file
     move(abs_path, file_path)

Check out this : Search and replace a line in a file in Python

Upvotes: 0

Related Questions