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"cell_type": "markdown",
"metadata": {},
"source": [
"Notes supporting [issue #256](https://github.com/alimanfoo/petl/issues/256)."
]
},
{
"cell_type": "code",
"collapsed": false,
"input": [
"import petl.interactive as etl"
],
"language": "python",
"metadata": {},
"outputs": [],
"prompt_number": 1
},
{
"cell_type": "code",
"collapsed": false,
"input": [
"t1 = etl.wrap([['foo', 'bar'], [1, 'a'], [2, 'b']])\n",
"t1"
],
"language": "python",
"metadata": {},
"outputs": [
{
"html": [
"\r\n",
"\r\n",
"\r\n",
"| foo | \r\n",
"bar | \r\n",
"
\r\n",
"\r\n",
"\r\n",
"\r\n",
"| 1 | \r\n",
"a | \r\n",
"
\r\n",
"\r\n",
"| 2 | \r\n",
"b | \r\n",
"
\r\n",
"\r\n",
"
\r\n"
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"metadata": {},
"output_type": "pyout",
"prompt_number": 2,
"text": [
"+-------+-------+\n",
"| 'foo' | 'bar' |\n",
"+=======+=======+\n",
"| 1 | 'a' |\n",
"+-------+-------+\n",
"| 2 | 'b' |\n",
"+-------+-------+"
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}
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"prompt_number": 2
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{
"cell_type": "code",
"collapsed": false,
"input": [
"t2 = etl.wrap([['foo', 'bar'], [1, 'a'], [2, 'c']])\n",
"t2"
],
"language": "python",
"metadata": {},
"outputs": [
{
"html": [
"\r\n",
"\r\n",
"\r\n",
"| foo | \r\n",
"bar | \r\n",
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\r\n",
"\r\n",
"\r\n",
"\r\n",
"| 1 | \r\n",
"a | \r\n",
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\r\n",
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"| 2 | \r\n",
"c | \r\n",
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"+-------+-------+\n",
"| 'foo' | 'bar' |\n",
"+=======+=======+\n",
"| 1 | 'a' |\n",
"+-------+-------+\n",
"| 2 | 'c' |\n",
"+-------+-------+"
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{
"cell_type": "code",
"collapsed": false,
"input": [
"t3 = etl.merge(t1, t2, key='foo')\n",
"t3"
],
"language": "python",
"metadata": {},
"outputs": [
{
"html": [
"\r\n",
"\r\n",
"\r\n",
"| foo | \r\n",
"bar | \r\n",
"
\r\n",
"\r\n",
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"\r\n",
"| 1 | \r\n",
"a | \r\n",
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"| 2 | \r\n",
"Conflict(['c', 'b']) | \r\n",
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"prompt_number": 5,
"text": [
"+-------+----------------------+\n",
"| 'foo' | 'bar' |\n",
"+=======+======================+\n",
"| 1 | 'a' |\n",
"+-------+----------------------+\n",
"| 2 | Conflict(['c', 'b']) |\n",
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"metadata": {},
"source": [
"The problem with the above is that you cannot tell from inspecting *t3* alone which conflicting value comes from which source.\n",
"\n",
"A workaround as suggested by [@pawl](https://github.com/pawl) is to use the [*conflicts()*](http://petl.readthedocs.org/en/latest/#petl.conflicts) function, e.g.: "
]
},
{
"cell_type": "code",
"collapsed": false,
"input": [
"t4 = (etl\n",
" .cat(\n",
" t1.addfield('source', 1),\n",
" t2.addfield('source', 2)\n",
" )\n",
" .conflicts(key='foo', exclude='source')\n",
")\n",
"t4"
],
"language": "python",
"metadata": {},
"outputs": [
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"+-------+-------+----------+\n",
"| 'foo' | 'bar' | 'source' |\n",
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"| 2 | 'b' | 1 |\n",
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"| 2 | 'c' | 2 |\n",
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