New to python - Just a question
Rhodri James
rhodri at kynesim.co.uk
Fri Jul 3 13:15:59 EDT 2020
On 03/07/2020 11:09, Daley Okuwa via Python-list wrote:
>
> Please can someone help
>
> Write an algorithm (choose the language you prefer) that given a character string, for instance {‘c’,’a’,’i’,’o’,’p’,’a’}, will print out the list of characters appearing at least 2 times. In this specific example, it would return {‘a’}. Afterwards, comment out the cost in terms of space and time.
The first thing to do with any problem is to break it down into bits.
In the case of Python, writing them out as "pseudo-code" instructions
often helps. In this case you have:
Set up something to count letters with
For each letter in the string:
If we haven't seen this letter before:
Set the counter for the letter to 1
Else:
Add 1 to the counter for the letter
For each counter:
If the count is 2 or more:
Print the letter
Now there are a lot of possible ways to write that, but they mostly come
down to deciding what data structure to use to count letters with. Have
a browse through a tutorial (or the standard library if you are feeling
adventurous) and see what you think might work, then try it.
> Write a bash/python script that takes a directory as an argument and output the total lines of code in *.cpp files recursively.
In bash, what existing commands count things? If you don't know, how
might you find out? Then you have to figure out how to do that for each
*.cpp file in a directory, and add the totals together.
In Python, you can read a file one line at a time, so how to count the
number of lines in a file should be pretty obvious. Figuring out how to
do that for every *.cpp file in a directory will involve looking through
the standard library, or getting a bash script to do it for you :-)
--
Rhodri James *-* Kynesim Ltd
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