some advices about python coding

from 《learn python the hard way》
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Every if-statement must have an else. If this else should never be run because it doesn't make sense, then you must use a die function in the else that prints out an error message and dies, just like we did in the last exercise. This will find many errors.

Never nest if-statements more than 2 deep and always try to do them 1 deep. This means if you put an if in an if then you should be looking to move that second if into another function.

Treat if-statements like paragraphs, where each if,elif,else grouping is like a set of sentences. Put blank lines before and after. Your boolean tests should be simple. If they are complex, move their calculations to variables earlier in your function and use a good name for the variable.

The best way to debug a program is to use print to print out the values of variables at points in the program to see where they go wrong.

Make sure parts of your programs work as you work on them. Do not write massive files of code before you try to run them. Code a little, run a little, fix a little.

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Every if-statement must have an else. If this else should never be run because it doesn't make sense, then you must use a die function in the else that prints out an error message and dies, just like we did in the last exercise. This will find many errors.

Never nest if-statements more than 2 deep and always try to do them 1 deep. This means if you put an if in an if then you should be looking to move that second if into another function.

Treat if-statements like paragraphs, where each if,elif,else grouping is like a set of sentences. Put blank lines before and after. Your boolean tests should be simple. If they are complex, move their calculations to variables earlier in your function and use a good name for the variable.

The best way to debug a program is to use print to print out the values of variables at points in the program to see where they go wrong.

Make sure parts of your programs work as you work on them. Do not write massive files of code before you try to run them. Code a little, run a little, fix a little.


When scrutinizing the code, pay attention on:

1. Functions and what they do.
2. Where each variable is first given a value.
3. Any variables with the same names in different parts of the program. These may be trouble later.
4. Any if-statements without else clauses. Are they right?
5. Any while-loops that might not end.
6. Finally, any parts of code that you can’t understand for whatever reason.