Writing Files We can open a file object using the method write() to save the text file to a list. To write the mode, argument must be set to write w. Let’s write a file Example2.txt with the line: “This is line A”


# Write line to file

with open('/resources/data/Example2.txt', 'w') as writefile:
    writefile.write("This is line A")

We can read the file to see if it worked:


# Read file

with open('drive/app/xample2.txt', 'r') as testwritefile:
    print(testwritefile.read())

We can write multiple lines:


# Write lines to file

with open('/resources/data/Example2.txt', 'w') as writefile:
    writefile.write("This is line A\n")
    writefile.write("This is line B\n")

The method .write() works similar to the method .readline(), except instead of reading a new line it writes a new line. The process is illustrated in the figure , the different colour coding of the grid represents a new line added to the file after each method call.
You can check the file to see if your results are correct


# Check whether write to file

with open('/resources/data/Example2.txt', 'r') as testwritefile:
    print(testwritefile.read())

By setting the mode argument to append a you can append a new line as follows:


# Write a new line to text file

with open('/resources/data/Example2.txt', 'a') as testwritefile:
    testwritefile.write("This is line C\n")

You can verify the file has changed by running the following cell:


# Verify if the new line is in the text file

with open('/resources/data/Example2.txt', 'r') as testwritefile:
    print(testwritefile.read())

We write a list to a .txt file as follows:


# Sample list of text

Lines = ["This is line A\n", "This is line B\n", "This is line C\n"]
Lines


# Write the strings in the list to text file

with open('Example2.txt', 'w') as writefile:
    for line in Lines:
        print(line)
        writefile.write(line)

We can verify the file is written by reading it and printing out the values:


# Verify if writing to file is successfully executed

with open('Example2.txt', 'r') as testwritefile:
    print(testwritefile.read())

We can again append to the file by changing the second parameter to a. This adds the code:


# Append the line to the file

with open('Example2.txt', 'a') as testwritefile:
    testwritefile.write("This is line D\n")

We can see the results of appending the file:


# Verify if the appending is successfully executed

with open('Example2.txt', 'r') as testwritefile:
    print(testwritefile.read())

Copy a File Let's copy the file Example2.txt to the file Example3.txt:


# Copy file to another

with open('Example2.txt','r') as readfile:
    with open('Example3.txt','w') as writefile:
          for line in readfile:
                writefile.write(line)

We can read the file to see if everything works:


# Verify if the copy is successfully executed

with open('Example3.txt','r') as testwritefile:
    print(testwritefile.read())

Write and Save Files in Python