September Morn Update

Task/Align-columns/Python/align-columns-2.py

@@ -1,21 +1,18 @@
-txt = """Given$a$txt$file$of$many$lines,$where$fields$within$a$line$
+'''
+cat <<'EOF' > align_columns.dat
+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."""
+justified,$right$justified,$or$center$justified$within$its$column.
+EOF
+'''
 
-parts = [line.rstrip("$").split("$") for line in txt.splitlines()]
-
-max_widths = {}
-for line in parts:
-    for i, word in enumerate(line):
-        max_widths[i] = max(max_widths.get(i, 0), len(word))
-
-for i, justify in enumerate([str.ljust, str.center, str.rjust]):
-    print ["Left", "Center", "Right"][i], " column-aligned output:\n"
-    for line in parts:
-        for j, word in enumerate(line):
-            print justify(word, max_widths[j]),
-        print
-    print "- " * 52
+for align in '<^>':
+  rows = [ line.strip().split('$') for line in open('align_columns.dat') ]
+  fmts = [ '{:%s%d}' % (align, max( len(row[i]) if i < len(row) else 0 for row in rows ))
+           for i in range(max(map(len, rows))) ]
+  for row in rows:
+    print(' '.join(fmts).format(*(row + [''] * len(fmts))))
+  print('')

Task/Align-columns/Python/align-columns-3.py

@@ -1,18 +1,21 @@
-'''
-cat <<'EOF' > align_columns.dat
-Given$a$text$file$of$many$lines,$where$fields$within$a$line$
+txt = """Given$a$txt$file$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.
-EOF
-'''
+justified,$right$justified,$or$center$justified$within$its$column."""
 
-for align in '<^>':
-  rows = [ line.strip().split('$') for line in open('align_columns.dat') ]
-  fmts = [ '{:%s%d}' % (align, max( len(row[i]) if i < len(row) else 0 for row in rows ))
-           for i in range(max(map(len, rows))) ]
-  for row in rows:
-    print(' '.join(fmts).format(*(row + [''] * len(fmts))))
-  print('')
+parts = [line.rstrip("$").split("$") for line in txt.splitlines()]
+
+max_widths = {}
+for line in parts:
+    for i, word in enumerate(line):
+        max_widths[i] = max(max_widths.get(i, 0), len(word))
+
+for i, justify in enumerate([str.ljust, str.center, str.rjust]):
+    print ["Left", "Center", "Right"][i], " column-aligned output:\n"
+    for line in parts:
+        for j, word in enumerate(line):
+            print justify(word, max_widths[j]),
+        print
+    print "- " * 52

Task/Align-columns/Python/align-columns-4.py

@@ -0,0 +1,75 @@
+'''Variously aligned columns
+   from delimited text.
+'''
+
+from functools import reduce
+from itertools import repeat
+
+
+# TEST ----------------------------------------------------
+# main :: IO ()
+def main():
+    '''Test of three alignments.'''
+
+    txt = '''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.'''
+
+    rows = [x.split('$') for x in txt.splitlines()]
+    table = paddedRows(max(map(len, rows)))('')(rows)
+
+    print('\n\n'.join(map(
+        alignedTable(table)('  '),
+        [-1, 0, 1]  # Left, Center, Right
+    )))
+
+
+# alignedTable :: [[String]] -> Alignment -> String -> String
+def alignedTable(rows):
+    '''Tabulation of rows of cells, with cell alignment
+       specified by:
+           eAlign -1 = left
+           eAlign  0 = center
+           eAlign  1 = right
+       and separator between columns
+       supplied by the `sep` argument.
+    '''
+    def go(sep, eAlign):
+        lcr = ['ljust', 'center', 'rjust'][1 + eAlign]
+
+        # nextAlignedCol :: [[String]] -> [String] -> [[String]]
+        def nextAlignedCol(cols, col):
+            w = max(len(cell) for cell in col)
+            return cols + [
+                [getattr(s, lcr)(w, ' ') for s in col]
+            ]
+
+        return '\n'.join([
+            sep.join(cells) for cells in
+            zip(*reduce(nextAlignedCol, zip(*rows), []))
+        ])
+    return lambda sep: lambda eAlign: go(sep, eAlign)
+
+
+# GENERIC -------------------------------------------------
+
+# paddedRows :: Int -> a -> [[a]] -> [[a]]
+def paddedRows(n):
+    '''A list of rows of even length,
+       in which each may be padded (but
+       not truncated) to length n with
+       appended copies of value v.'''
+    def go(v, xs):
+        def pad(x):
+            d = n - len(x)
+            return (x + list(repeat(v, d))) if 0 < d else x
+        return [pad(row) for row in xs]
+    return lambda v: lambda xs: go(v, xs) if xs else []
+
+
+# MAIN ---
+if __name__ == '__main__':
+    main()