37 lines
1.3 KiB
Python
37 lines
1.3 KiB
Python
# Import the argv tool from system tools.
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from sys import argv
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# Grab some command line arguments with argv.
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script, input_file = argv
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def print_all(f): # Define a function with one argument.
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print(f.read()) # Read an a file passed to this function.
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def rewind(f): # Define a function with one argument.
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f.seek(0) # Start from the first line.
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def print_a_line(line_count, f): # Define a function with two arguments.
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print(line_count, f.readline()) # Print the line.
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current_file = open(input_file) # Open the file input_file as "current_file"
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print("First let's print the whole file:\n") # Tell the user we're printing the whole file.
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print_all(current_file) # Print the whole file.
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print("Now let's rewind, kind of like a tape.") # Tell the user we're starting over.
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rewind(current_file) # Print the first line.
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print("Let's print three lines:") # Tell the user we're printing three lines.
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current_line = 1 # Set the current line to the second line.
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print_a_line(current_line, current_file) # Print the current line.
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current_line = current_line + 1 # Increment the current line by one, making it the third line.
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print_a_line(current_line, current_file) # Print the current line.
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current_line = current_line + 1 # Increment the current line by one, making it the fourth line.
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print_a_line(current_line, current_file) # Print the current line.
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