Print string to text file

Question

I'm using Python to open a text document:

text_file = open("Output.txt", "w")  text_file.write("Purchase Amount: " 'TotalAmount')  text_file.close() 

I want to substitute the value of a string variable TotalAmount into the text document. Can someone please let me know how to do this?

Answer 1

It is strongly advised to use a context manager. As an advantage, it is made sure the file is always closed, no matter what:

with open("Output.txt", "w") as text_file:     text_file.write("Purchase Amount: %s" % TotalAmount) 

This is the explicit version (but always remember, the context manager version from above should be preferred):

text_file = open("Output.txt", "w") text_file.write("Purchase Amount: %s" % TotalAmount) text_file.close() 

If you're using Python2.6 or higher, it's preferred to use str.format()

with open("Output.txt", "w") as text_file:     text_file.write("Purchase Amount: {0}".format(TotalAmount)) 

For python2.7 and higher you can use {} instead of {0}

In Python3, there is an optional file parameter to the print function

with open("Output.txt", "w") as text_file:     print("Purchase Amount: {}".format(TotalAmount), file=text_file) 

Python3.6 introduced f-strings for another alternative

with open("Output.txt", "w") as text_file:     print(f"Purchase Amount: {TotalAmount}", file=text_file) 

Answer 2

In case you want to pass multiple arguments you can use a tuple

price = 33.3 with open("Output.txt", "w") as text_file:     text_file.write("Purchase Amount: %s price %f" % (TotalAmount, price)) 

More: Print multiple arguments in python