46 lines
1.8 KiB
Python
46 lines
1.8 KiB
Python
from StringIO import StringIO
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textinfile = '''Given$a$text$file$of$many$lines,$where$fields$within$a$line$
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are$delineated$by$a$single$'dollar'$character,$write$a$program
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that$aligns$each$column$of$fields$by$ensuring$that$words$in$each$
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column$are$separated$by$at$least$one$space.
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Further,$allow$for$each$word$in$a$column$to$be$either$left$
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justified,$right$justified,$or$center$justified$within$its$column.'''
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j2justifier = dict(L=str.ljust, R=str.rjust, C=str.center)
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def aligner(infile, justification = 'L'):
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''' \
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Justify columns of textual tabular input where the row separator is the newline
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and the field separator is a 'dollar' character.
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justification can be L, R, or C; (Left, Right, or Centered).
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Return the justified output as a string
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'''
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assert justification in j2justifier, "justification can be L, R, or C; (Left, Right, or Centered)."
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justifier = j2justifier[justification]
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fieldsbyrow= [line.strip().split('$') for line in infile]
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# pad to same number of fields per row
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maxfields = max(len(row) for row in fieldsbyrow)
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fieldsbyrow = [fields + ['']*(maxfields - len(fields))
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for fields in fieldsbyrow]
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# rotate
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fieldsbycolumn = zip(*fieldsbyrow)
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# calculate max fieldwidth per column
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colwidths = [max(len(field) for field in column)
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for column in fieldsbycolumn]
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# pad fields in columns to colwidth with spaces
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fieldsbycolumn = [ [justifier(field, width) for field in column]
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for width, column in zip(colwidths, fieldsbycolumn) ]
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# rotate again
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fieldsbyrow = zip(*fieldsbycolumn)
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return "\n".join( " ".join(row) for row in fieldsbyrow)
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for align in 'Left Right Center'.split():
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infile = StringIO(textinfile)
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print "\n# %s Column-aligned output:" % align
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print aligner(infile, align[0])
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