Question

I’m attempting to learn a few languages and as such I am doing the same problem on different languages. Here is my code:

def read_one_file():
    with open('C:\Python27\inventory.dat', 'r') as f:
        invid = f.readline().strip()
        invtype = f.readline().strip()
        price = f.readline().strip()
        stock = f.readline().strip()
        title = f.readline().strip()
        author = f.readline().strip()
        published = f.readline().strip()

        return invid, invtype, price, stock, title, author, published


def write_one_file(holdId, holdType, holdPrice, holdStock, holdTitle, holdAuthor, holdPublished):
    with open('C:\Python27\inventory.dat', 'w') as f:
        invid = holdId
        price = holdPrice
        newstock = holdStock
        published = holdPublished
        f.write("Item Id: %s\n" %invid)
        f.write("Item Type: %s\n" %holdType)
        f.write("Item Price: %s\n" %price)
        f.write("Number In Stock: %s\n" %newstock)
        f.write("Title: %s\n" %holdTitle)
        f.write("Author: %s\n" %holdAuthor)
        f.write("Published: %s\n" %holdPublished)
        return

invid, invtype, price, stock, title, author, published = read_one_file()

print "Update Number In Stock"
print "----------------------"
print "Item ID: ", invid
print "Item Type: ", invtype
print "Price: ", price
print "Number In Stock: ", stock
print "Title: ", title
print "Author/Artist: ", author
print "Published: ", published
print "----------------------"
print "Please Enter New Stock Number: "
newstock = raw_input(">")


write_one_file(invid, invtype, price, newstock, title, author, published)

EDIT: I’ve tried using str() to convert but still doesn’t run.
EDIT2: I ended up changing %d to %s and seems to work. The only issue is when I run it, it tends to put book on line with 123456.

What ends up happening in the console

    Update Number In Stock
----------------------
Item ID:  123456book
Item Type:  69.99
Price:  20
Number In Stock:  
Title:  Walter_Savitch
Author/Artist:  2011
Published:  
----------------------
Please Enter New Stock Number: 
>

this is the .txt file:

123456book
69.99
20

Walter_Savitch
2011

something with a newline?

Answer 1

f.write() expects a string as an argument. You’re defining invid, invtype, etc as tuples, which are not automatically converted to strings. You can either explicitly convert them, using the str() function, or more likely what you’d like is to use some string formatting, e.g.:

"Number in stock%d"%nrStock

where “%d” indicates that nrStock is an integer.

You’ll note that I’ve renamed your d variable to nrStock. It’s typically good practice to use descriptive variable names, or an even better idea might be to use a dictionary.