Importing text files line by line
For large files, we may not want to print all of their content to the shell:
you may wish to print only the first few lines. Enter the .readline() method,
which allows you to do this. When a file called file is open, you can print
out the first line by executing file.readline(). If you execute the same
command again, the second line will print, and so on.
In the introductory video, Hugo also introduced the concept of a context manager. He showed that you can bind a variable file by using a context manager construct:
with open('huck_finn.txt') as file:
While still within this construct, the variable file will be bound to open('huck_finn.txt');
thus, to print the file to the shell, all the code you need to execute is:
with open('huck_finn.txt') as file:
print(file.readline())
You'll now use these tools to print the first few lines of moby_dick.txt!
This exercise is part of the course
Introduction to Importing Data in Python
Exercise instructions
- Open
moby_dick.txtusing thewithcontext manager and the variablefile. - Print the first three lines of the file to the shell by using
.readline()three times within the context manager.
Hands-on interactive exercise
Have a go at this exercise by completing this sample code.
# Read & print the first 3 lines
with open('moby_dick.txt') as ____:
print(____)
print(____)
print(____)