1.9 KiB
1.9 KiB
Python applying learnings from 1..6
Lecture notes
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Previous topics covered:
- Printing
- Formatting
- Variables
- Escape Sequences
- Inputting text
- Reading arguments / using argv
- Reading files
- Defining methods
- Boolean logic
- Branching using if/else/elif
- Loops: for/while
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Today we write a calculator that saves results in a file in python
- How it works in general You read the input until you read a line that only contains a "q". Every input line consists of numbers separated by a space. For instance "4 5 9". You will need to .split() the input.
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Steps
- Create a python script named "calc.py"
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It takes 1 command line argument (argv), which is the filename
- We will store the calculations and results in this file
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Create a method named "input_and_calculate_one_line"
- It does not have any arguments
- It reads one line via input
- It splits the input (let's say "4 5 9" => [ "4", "5", "9") ])
- It calculates the result (f.i. 4+5+9 = 18) and stores it in a variable (use sum over the list)
- It returns a string of the format "4 + 5 + 9 = 18"
- If the line only contains a "q" it return "" (an empty string)
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Create a method named "editor" that takes a filename as an argument
- It opens the file for writing
- It uses input_and_calculate_one_line in a while loop
- while the return result is not "", we append the string to the file
- When the return result is "", the function exits
State:
input_and_calculate_one_line is complete, however it's probably a garbage implementation. Spent too much time on converting back and forth and getting the output right.
Editor (file io) is not complete yet