User Inputs and File Handling - Learn Python with BNHR

User Input¶

Python allows users to get a user input using the input() method

pangalan = input("Ano ang iyong pangalan?")
print("Ikaw ay si {}".format(pangalan))

Files¶

Aside from standard inputs, Python has several functions for creating, reading, updating, and deleting files.

open(): key function for working with files
two parameters
- filename
- mode
  - “r” - Read - Default value. Opens a file for reading, error if the file does not exist
  - “a” - Append - Opens a file for appending, creates the file if it does not exist
  - “w” - Write - Opens a file for writing, creates the file if it does not exist
  - “x” - Create - Creates the specified file, returns an error if the file exists
- you can also can specify if the file should be handled as binary or text mode
  - “t” - Text - Default value. Text mode
  - “b” - Binary - Binary mode (e.g. images)

Creating a file¶

First, let’s create a dummy dataset to work with. We use the open() function with mode 'w' (write).

'w': Write (Overwrites the file if it exists).
'a': Append (Adds to the end of the file).

# Create a sample text file representing a list of farms
filename = "barangay_farms.txt"

with open(filename, "w") as f:
    f.write("Farm_ID,Crop,Hectares\n")
    f.write("001,Palay,2.5\n")
    f.write("002,Corn,1.0\n")
    f.write("003,Coconut,5.0\n")
    f.write("004,Mango,3.2\n")

Working with files¶

Now, let’s read the file we just created. The best practice is to use the with statement, it automatically closes the file even if your code crashes.

'r': Read (Default mode).

# Reading the file line by line
with open(filename, "r") as f:
    # Loop through each line in the file
    for line in f:
        # .strip() removes the invisible newline character (\n) at the end
        print(line.strip())

Reading data from a the¶

Python can read data directly from the web. This is crucial for accessing modern APIs or cloud-stored data.

We will use the standard json and urllib libraries to fetch a GeoJSON file (a map file format).

import json
import urllib.request

# URL to a sample GeoJSON
url = "https://github.com/opengeos/datasets/releases/download/world/world_cities.geojson"

try:
    # 1. Open the URL
    with urllib.request.urlopen(url) as response:
        # 2. Read and Parse the JSON
        data = json.loads(response.read().decode())
    
    # 3. Explore the Data
    feature_count = len(data['features'])
    first_state = data['features'][0]['properties']['name']
    
    print(f"Type: {data['type']}")
    print(f"Total Features: {feature_count}")
    print(f"First Feature Name: {first_state}")

except urllib.error.URLError as e:
    print(f"Connection Error: {e}")