Align columns
Given a text file of many lines, where fields within a line are delineated by a single 'dollar' character, write a program that aligns each column of fields by ensuring that words in each column are separated by at least one space. Further, allow for each word in a column to be either left justified, right justified, or center justified within its column.
You are encouraged to solve this task according to the task description, using any language you may know.
Use the following text to test your programs:
Given$a$text$file$of$many$lines,$where$fields$within$a$line$ are$delineated$by$a$single$'dollar'$character,$write$a$program that$aligns$each$column$of$fields$by$ensuring$that$words$in$each$ column$are$separated$by$at$least$one$space. Further,$allow$for$each$word$in$a$column$to$be$either$left$ justified,$right$justified,$or$center$justified$within$its$column.
ALGOL 68
STRING nl = REPR 10; STRING text in list := "Given$a$text$file$of$many$lines,$where$fields$within$a$line$"+nl+ "are$delineated$by$a$single$'dollar'$character,$write$a$program"+nl+ "that$aligns$each$column$of$fields$by$ensuring$that$words$in$each$"+nl+ "column$are$separated$by$at$least$one$space."+nl+ "Further,$allow$for$each$word$in$a$column$to$be$either$left$"+nl+ "justified,$right$justified,$or$center$justified$within$its$column."; MODE PAGE = FLEX[0,0]STRING; PAGE page; PROC flex page = (PAGE in page, INT row, col)PAGE:( HEAP FLEX[row, col]STRING out page; out page[:1 UPB in page, :2 UPB in page] := in page; FOR r TO row DO FOR c FROM 2 UPB in page + 1 TO col DO out page[r,c]:="" OD OD; FOR r FROM 1 UPB in page + 1 TO row DO FOR c FROM 1 TO col DO out page[r,c]:="" OD OD; out page ); FILE text in file; associate(text in file, text in list); make term(text in file, "$"); on physical file end(text in file, (REF FILE skip)BOOL: stop iteration); on logical file end(text in file, (REF FILE skip)BOOL: stop iteration); FOR row DO on line end(text in file, (REF FILE skip)BOOL: stop iteration); FOR col DO STRING tok; getf(text in file, ($gx$,tok)); IF row > 1 UPB page THEN page := flex page(page, row, 2 UPB page) FI; IF col > 2 UPB page THEN page := flex page(page, 1 UPB page, col) FI; page[row,col]:=tok OD; stop iteration: SKIP OD; stop iteration: SKIP; BEGIN PROC aligner = (PAGE in page, PROC (STRING,INT)STRING aligner)VOID:( PAGE page := in page; [2 UPB page]INT max width; FOR col TO 2 UPB page DO INT max len:=0; FOR row TO UPB page DO IF UPB page[row,col]>max len THEN max len:=UPB page[row,col] FI OD; FOR row TO UPB page DO page[row,col] := aligner(page[row,col], maxlen) OD OD; printf(($n(UPB page)(n(2 UPB page -1)(gx)gl)$,page)) ); PROC left = (STRING in, INT len)STRING: in + " "*(len - UPB in), right = (STRING in, INT len)STRING: " "*(len - UPB in) + in, centre = (STRING in, INT len)STRING: ( INT pad=len-UPB in; pad%2*" "+ in + (pad-pad%2)*" " ); []STRUCT(STRING name, PROC(STRING,INT)STRING align) aligners = (("Left",left), ("Left",right), ("Centre",centre)); FOR index TO UPB aligners DO print((new line, "# ",name OF aligners[index]," Column-aligned output:",new line)); aligner(page, align OF aligners[index]) OD END
OCaml
<ocaml>#load "str.cma" open Str
let input = "\ Given$a$text$file$of$many$lines,$where$fields$within$a$line$ are$delineated$by$a$single$'dollar'$character,$write$a$program that$aligns$each$column$of$fields$by$ensuring$that$words$in$each$ column$are$separated$by$at$least$one$space. Further,$allow$for$each$word$in$a$column$to$be$either$left$ justified,$right$justified,$or$center$justified$within$its$column."
let () =
let lines = split (regexp_string "\n") input in let fields_l = List.map (split (regexp_string "$")) lines in let fields_l = List.map Array.of_list fields_l in let n = (* number of columns *) List.fold_left (fun n fields -> max n (Array.length fields)) 0 fields_l in let pads = Array.make n 0 in List.iter ( (* calculate the max padding for each column *) Array.iteri (fun i word -> pads.(i) <- max pads.(i) (String.length word)) ) fields_l;
let print f = List.iter (fun fields -> Array.iteri (fun i word -> f word (pads.(i) - (String.length word)) ) fields; print_newline() ) fields_l; in
(* left column-aligned output *) print (fun word pad -> let spaces = String.make pad ' ' in Printf.printf "%s%s " word spaces);
(* right column-aligned output *) print (fun word pad -> let spaces = String.make pad ' ' in Printf.printf "%s%s " spaces word);
(* center column-aligned output *) print (fun word pad -> let pad1 = pad / 2 in let pad2 = pad - pad1 in let sp1 = String.make pad1 ' ' in let sp2 = String.make pad2 ' ' in Printf.printf "%s%s%s " sp1 word sp2);
- </ocaml>
Python
<python>from StringIO import StringIO
textinfile = Given$a$text$file$of$many$lines,$where$fields$within$a$line$ are$delineated$by$a$single$'dollar'$character,$write$a$program that$aligns$each$column$of$fields$by$ensuring$that$words$in$each$ column$are$separated$by$at$least$one$space. Further,$allow$for$each$word$in$a$column$to$be$either$left$ justified,$right$justified,$or$center$justified$within$its$column.
j2justifier = dict(L=str.ljust, R=str.rjust, C=str.center)
def aligner(infile, justification = 'L'):
\ Justify columns of textual tabular input where the record separator is the newline and the field separator is a 'dollar' character. justification can be L, R, or C; (Left, Right, or Centered). Return the justified output as a string assert justification in 'LRC', "justification can be L, R, or C; (Left, Right, or Centered)." justifier = j2justifier[justification] fieldsbyrecord= [line.strip().split('$') for line in infile] # pad to same number of fields per record maxfields = max(len(record) for record in fieldsbyrecord) fieldsbyrecord = [fields + []*(maxfields - len(fields)) for fields in fieldsbyrecord] # rotate fieldsbycolumn = zip(*fieldsbyrecord) # calculate max fieldwidth per column colwidths = [max(len(field) for field in column) for column in fieldsbycolumn] # pad fields in columns to colwidth with spaces fieldsbycolumn = [ [justifier(field, width) for field in column] for width, column in zip(colwidths, fieldsbycolumn) ] # rotate again fieldsbyrecord = zip(*fieldsbycolumn)
return "\n".join( " ".join(record) for record in fieldsbyrecord)
for align in 'Left Right Center'.split():
infile = StringIO(textinfile) print "\n# %s Column-aligned output:" % align print aligner(infile, align[0])</python>
Example output:
# Left Column-aligned output: Given a text file of many lines, where fields within a line are delineated by a single 'dollar' character, write a program that aligns each column of fields by ensuring that words in each column are separated by at least one space. Further, allow for each word in a column to be either left justified, right justified, or center justified within its column. # Right Column-aligned output: Given a text file of many lines, where fields within a line are delineated by a single 'dollar' character, write a program that aligns each column of fields by ensuring that words in each column are separated by at least one space. Further, allow for each word in a column to be either left justified, right justified, or center justified within its column. # Center Column-aligned output: Given a text file of many lines, where fields within a line are delineated by a single 'dollar' character, write a program that aligns each column of fields by ensuring that words in each column are separated by at least one space. Further, allow for each word in a column to be either left justified, right justified, or center justified within its column.