File i/o
Often times, you will have data stored as an external file. You will need to take this file as input and use it in your code. In this example, we will be using the sys library to take a file as input from the command line. We will iterate over each line of the file and perform a search on the lines.
To begin, we create a file: ‘lookup.csv’
%%file lookup.csv Date,Time May,4.15 April,16.00
Code:
%%file io.py #!/usr/bin/python import sys import re with open(sys.argv[1], 'r') as file: for line in file: line = re.search(r'May,.*', line) # Regex print(line)
Running the Code:
!python io.py lookup.csv
Breakdown:
- The sys library is used to accept arguments from the command line
- The re library is used to look for regular expressions within the file
with open(sys[1],'r') as file:
allows argument 1 from the command line to be opened as stored in the variablefile
for line in file:
Using a for loop, each line of the file is iterated over- A search is done on each line for
May,.*
and matches are printed