For 2023 (and 2024 ...) - we are now fully retired from IT training. We have made many, many friends over 25 years of teaching about Python, Tcl, Perl, PHP, Lua, Java, C and C++ - and MySQL, Linux and Solaris/SunOS too. Our training notes are now very much out of date, but due to upward compatability most of our examples remain operational and even relevant ad you are welcome to make us if them "as seen" and at your own risk.
Lisa and I (Graham) now live in what was our training centre in Melksham - happy to meet with former delegates here - but do check ahead before coming round. We are far from inactive - rather, enjoying the times that we are retired but still healthy enough in mind and body to be active!
I am also active in many other area and still look after a lot of web sites - you can find an index ((here)) |
Dynamically formatting your results (Lua)
Scenario: You're producing a short (text) table of results and you want to keep it reasonably small - not a great deal of white space, but the data in some of your columns differs dramatically from one set of results to another. How can you do it?
Discussion: You can use your traditional "printf" type formatting in C, Perl, PHP, Python (via the % operator), Lua (string.format) and Tcl (string format) to give each field a width, but you'll need to ensure that the fields are wide enough to take the data to be placed in them every time, or accept occasional spillages when the data "busts its bank".
Solution: Parse the data for the report before you print anything out at all, and calculate the maximum width for each field for the current report. Then make up your own dynamic formatting string for use just on this occaasion. Here's an example of what I mean:
oak = {"beer","beer","beer","beer","beer","legs",
"spilled spaghetti sauce","top","draw",
"spit","polish","secret"}
table.sort(oak)
-- ====================================
syze = #oak[1]
for k=2,#oak do
if syze < #oak[k] then syze = #oak[k] end
end
clen = #(string.format("%d",#oak));
using = "%"..clen.."d %"..syze.."s"
print ("Output format: " .. using)
for k,v in ipairs(oak) do
print (string.format(using,k,v))
end
-- ====================================
And the result:
Output format: %2d %23s
1 beer
2 beer
3 beer
4 beer
5 beer
6 draw
7 legs
8 polish
9 secret
10 spilled spaghetti sauce
11 spit
12 top
Notes: 1. If the question had been asked for web use, I would have used a browser and a table in my html to do the dynamic formatting
2. The code in the ========== section should be saved as a function for re-use later (written 2009-11-10, updated 2009-11-11)
Associated topics are indexed as below, or enter http://melksh.am/nnnn for individual articles U104 - Lua - Strings and the String library. [1744] Lua examples, Lua Courses - (2008-08-08) [2348] Finding literals rather than patterns in Lua - (2009-08-11) [2357] Checking if the user has entered a number (Lua) - (2009-08-13) [4274] String formatting in Lua - string.format as a wrapper for sprintf - (2014-05-07)
Some other Articles
Learning to program in ...Melksham manslaughter case concludes - sort ofMonday night, Tuesday nightSimplesDynamically formatting your results (Lua)ourdog is Greyhound, Staffie and Ginger CakeRemembrance Sunday 2009, MelkshamBrown horses in MelkshamA better design of mouthPlanning the future of Wiltshire
|
4759 posts, page by page
Link to page ... 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17, 18, 19, 20, 21, 22, 23, 24, 25, 26, 27, 28, 29, 30, 31, 32, 33, 34, 35, 36, 37, 38, 39, 40, 41, 42, 43, 44, 45, 46, 47, 48, 49, 50, 51, 52, 53, 54, 55, 56, 57, 58, 59, 60, 61, 62, 63, 64, 65, 66, 67, 68, 69, 70, 71, 72, 73, 74, 75, 76, 77, 78, 79, 80, 81, 82, 83, 84, 85, 86, 87, 88, 89, 90, 91, 92, 93, 94, 95, 96 at 50 posts per page
This is a page archived from The Horse's Mouth at
http://www.wellho.net/horse/ -
the diary and writings of Graham Ellis.
Every attempt was made to provide current information at the time the
page was written, but things do move forward in our business - new software
releases, price changes, new techniques. Please check back via
our main site for current courses,
prices, versions, etc - any mention of a price in "The Horse's Mouth"
cannot be taken as an offer to supply at that price.
Link to Ezine home page (for reading).
Link to Blogging home page (to add comments).
|
|