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| author | Paul McGuire <ptmcg@austin.rr.com> | 2015-12-31 00:55:47 +0000 |
|---|---|---|
| committer | Paul McGuire <ptmcg@austin.rr.com> | 2015-12-31 00:55:47 +0000 |
| commit | 401ba4a945b88f12e26495a82d4059d4adbaec92 (patch) | |
| tree | 9570287813d7358750ddd1ffe50ba60c0a999972 /src/examples/parseTabularData.py | |
| parent | c8e8c6592d625d24bc7c0ca34bcc527ec380c2d5 (diff) | |
| download | pyparsing-git-401ba4a945b88f12e26495a82d4059d4adbaec92.tar.gz | |
Added new example parseTabularData.py
Updated several examples to more current Python and pyparsing practices (and better Py2/Py3 cross-compatibility)
Diffstat (limited to 'src/examples/parseTabularData.py')
| -rw-r--r-- | src/examples/parseTabularData.py | 50 |
1 files changed, 50 insertions, 0 deletions
diff --git a/src/examples/parseTabularData.py b/src/examples/parseTabularData.py new file mode 100644 index 0000000..3846310 --- /dev/null +++ b/src/examples/parseTabularData.py @@ -0,0 +1,50 @@ +#
+# parseTabularData.py
+#
+# Example of parsing data that is formatted in a tabular listing, with
+# potential for missing values. Uses new addCondition method on
+# ParserElements.
+#
+# Copyright 2015, Paul McGuire
+#
+from pyparsing import col,Word,Optional,alphas,nums,ParseException
+
+table = """\
+ 1 2
+12345678901234567890
+COLOR S M L
+RED 10 2 2
+BLUE 5 10
+GREEN 3 5
+PURPLE 8"""
+
+# function to create column-specific parse conditions
+def mustMatchCols(startloc,endloc):
+ return lambda s,l,t: startloc <= col(l,s) <= endloc
+
+# helper to define values in a space-delimited table
+# (change empty_cell_is_zero to True if a value of 0 is desired for empty cells)
+def tableValue(expr, colstart, colend):
+ empty_cell_is_zero = False
+ if empty_cell_is_zero:
+ return Optional(expr.copy().addCondition(mustMatchCols(colstart,colend),
+ message="text not in expected columns"),
+ default=0)
+ else:
+ return Optional(expr.copy().addCondition(mustMatchCols(colstart,colend),
+ message="text not in expected columns"))
+
+
+# define the grammar for this simple table
+colorname = Word(alphas)
+integer = Word(nums).setParseAction(lambda t: int(t[0])).setName("integer")
+row = (colorname("name") +
+ tableValue(integer, 11, 12)("S") +
+ tableValue(integer, 15, 16)("M") +
+ tableValue(integer, 19, 20)("L"))
+
+# parse the sample text - skip over the header and counter lines
+for line in table.splitlines()[3:]:
+ print(line)
+ print(row.parseString(line).dump())
+ print('')
|