c# - Replacing specific numbers with String.Replace or Regex.Replace -


just having little problem in attempting string or regex replace on specific numbers in string.

for example, in string 

@1 having lunch @10 @11

i replace "@1", "@10" , "@11" respective values indicated below.

"@1" replace "@bob" "@10" replace "@joe" "@11" replace "@sam"

so final output like

"@bob having lunch @joe @sam"

attempts 

string.replace("@1", "@bob")

results in following

@bob having lunch @bob0 @bob1

any thoughts on solution might be?

assuming placeholder start @ , contain digits, can use regex.replace overload accepts matchevaluator delegate pick replacement value dictionary:

var regex = new regex(@"@\d+");  var dict = new dictionary<string, string> {     {"@1","@bob"},     {"@10","@joe"},     {"@11","@sam"}, };  var input = "@1 having lunch @10 @11"; var result=regex.replace(input, m => dict[m.value]);

the result "@bob having lunch @joe @sam"

there few advantages compared multiple string.replace calls:

  1. the code more concise, arbitrary number of placeholders
  2. you avoid mistakes due order of replacements (eg @11 must come before @1)
  3. it's faster because don't need search , replace placeholders multiple times
  4. it doesn't create temporary strings each parameter. can issue server applications because large number of orphaned strings put pressure on garbage collector

the reason advantages 3-4 regex parse input , create internal representation contains indexes match. when time comes create final string, uses stringbuilder read characters original string substitute replacement values when match encountered.


Comments

Post a Comment

Popular posts from this blog

javascript - RequestAnimationFrame not working when exiting fullscreen switching space on Safari -

request animation frame stops working when exiting fullscreen clicking on original space's safari window. fine if fullscreen mode canceled escape key or calling cancelfullscreen(). steps reproduce: open https://dl.dropboxusercontent.com/u/769042/prezi/safari-fullscreen.html click "draw raf", kittie appears click "fullscreen", go fullscreen click "draw raf", kittie appears go space original safari was, showing "click exit fullscreen mode", click anywhere, out fullscreen click "draw raf", nothing happens what handling click calling: window.requestanimationframe(draw); which draws on canvas context: function draw() { ctx.drawimage(img, math.random()*500|0, math.random()*400|0, 100, 100); } i checked .hidden , .visibilitystate, updated correctly. tested on osx 10.9.3, safari 7.0.4 (9537.76.4). has workaround/solution other switching old settimeout? this sounds webkit bug 88940 : using reque...
Read more

Why am I getting Internal .NET Framework Data Provider error 1025 when passing Method to where? -

i have method takes generic tentity overriden. it's signature follows: public virtual expression<func<aclproject, bool>> projectfilter(params tentity[] objs) { return (p) => objs.select(o => o.id).contains(p.id); } i filter query based on this: from p in db.somedbset db.aclprojects.where(projectfilter(p)).any() select p this results in 1025 error. (note doesn't matter body of projectfilter is, error still occurs. any ideas why? thanks!
Read more

postgresql - how to get points from linestring postgis -

i have linestring (0 0 , 2 4 , 5 5); i need output in form : x (1st cell) || y (2nd cell) 0 || 0 2 || 4 5 || 5 and same polygon. how ? you can use st_x , st_y in conjunction st_pointn x , y of individual points, , use generate_series create index each point of linestring, eg, with line (select st_geomfromtext('linestring(0 0, 2 4, 5 5)') geom) select st_x(st_pointn(geom,num)) x, st_y(st_pointn(geom,num)) y line, (select generate_series(1, (select st_numpoints(geom) line)) num) series;
Read more