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https://issues.apache.org/jira/browse/ARROW-2145?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=16377698#comment-16377698
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ASF GitHub Bot commented on ARROW-2145:
---------------------------------------
cpcloud commented on a change in pull request #1651:
ARROW-2145/ARROW-2153/ARROW-2157/ARROW-2160/ARROW-2177: [Python] Decimal
conversion not working for NaN values
URL: https://github.com/apache/arrow/pull/1651#discussion_r170755603
##########
File path: cpp/src/arrow/util/decimal.cc
##########
@@ -212,160 +253,124 @@ static void StringToInteger(const std::string& str,
Decimal128* out) {
}
}
-Status Decimal128::FromString(const std::string& s, Decimal128* out, int*
precision,
- int* scale) {
- // Implements this regex:
"(\\+?|-?)((0*)(\\d*))(\\.(\\d+))?((E|e)(\\+|-)?\\d+)?";
- if (s.empty()) {
- return Status::Invalid("Empty string cannot be converted to decimal");
- }
+static const boost::regex DECIMAL_REGEX(
+ // sign of the number
+ "(?<SIGN>[-+]?)"
- std::string::const_iterator charp = s.cbegin();
- std::string::const_iterator end = s.cend();
+ // digits around the decimal point
+
"(((?<LEFT_DIGITS>\\d+)\\.(?<FIRST_RIGHT_DIGITS>\\d*)|\\.(?<SECOND_RIGHT_DIGITS>\\d+)"
+ ")"
- char first_char = *charp;
- bool is_negative = false;
- if (first_char == '+' || first_char == '-') {
- is_negative = first_char == '-';
- ++charp;
- }
+ // optional exponent
+ "([eE](?<FIRST_EXP_VALUE>[-+]?\\d+))?"
- if (charp == end) {
- std::stringstream ss;
- ss << "Single character: '" << first_char << "' is not a valid decimal
value";
- return Status::Invalid(ss.str());
- }
+ // otherwise
+ "|"
- std::string::const_iterator numeric_string_start = charp;
+ // we're just an integer
+ "(?<INTEGER>\\d+)"
- DCHECK_LT(charp, end);
+ // or an integer with an exponent
+ "(?:[eE](?<SECOND_EXP_VALUE>[-+]?\\d+))?)");
- // skip leading zeros
- charp = std::find_if_not(charp, end, [](char value) { return value == '0';
});
+static inline bool is_zero_character(char c) { return c == '0'; }
- // all zeros and no decimal point
- if (charp == end) {
- if (out != NULLPTR) {
- *out = 0;
- }
+Status Decimal128::FromString(const std::string& s, Decimal128* out, int32_t*
precision,
+ int32_t* scale) {
+ if (s.empty()) {
+ return Status::Invalid("Empty string cannot be converted to decimal");
+ }
- // Not sure what other libraries assign precision to for this case (this
case of
- // a string consisting only of one or more zeros)
+ // case of all zeros
+ if (std::all_of(s.cbegin(), s.cend(), is_zero_character)) {
if (precision != NULLPTR) {
- *precision = static_cast<int>(charp - numeric_string_start);
+ *precision = 0;
}
if (scale != NULLPTR) {
*scale = 0;
}
+ *out = 0;
return Status::OK();
}
- std::string::const_iterator whole_part_start = charp;
+ boost::smatch results;
+ const bool matches = boost::regex_match(s, results, DECIMAL_REGEX);
+
+ if (!matches) {
+ std::stringstream ss;
+ ss << s << " does not match";
+ return Status::Invalid(ss.str());
Review comment:
Probably not, I'll fix.
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> [Python] Decimal conversion not working for NaN values
> ------------------------------------------------------
>
> Key: ARROW-2145
> URL: https://issues.apache.org/jira/browse/ARROW-2145
> Project: Apache Arrow
> Issue Type: Bug
> Components: C++, Python
> Affects Versions: 0.8.0
> Reporter: Antony Mayi
> Assignee: Phillip Cloud
> Priority: Major
> Labels: pull-request-available
>
> {code:python}
> import pyarrow as pa
> import pandas as pd
> import decimal
> pa.Table.from_pandas(pd.DataFrame({'a': [decimal.Decimal('1.1'),
> decimal.Decimal('NaN')]}))
> {code}
> throws following exception:
> {code}
> Traceback (most recent call last):
> File "<stdin>", line 1, in <module>
> File "pyarrow/table.pxi", line 875, in pyarrow.lib.Table.from_pandas
> (/arrow/python/build/temp.linux-x86_64-3.6/lib.cxx:44927)
> File "/lib/python3.6/site-packages/pyarrow/pandas_compat.py", line 350, in
> dataframe_to_arrays
> convert_types)]
> File "/lib/python3.6/site-packages/pyarrow/pandas_compat.py", line 349, in
> <listcomp>
> for c, t in zip(columns_to_convert,
> File "/lib/python3.6/site-packages/pyarrow/pandas_compat.py", line 345, in
> convert_column
> return pa.array(col, from_pandas=True, type=ty)
> File "pyarrow/array.pxi", line 170, in pyarrow.lib.array
> (/arrow/python/build/temp.linux-x86_64-3.6/lib.cxx:29224)
> File "pyarrow/array.pxi", line 70, in pyarrow.lib._ndarray_to_array
> (/arrow/python/build/temp.linux-x86_64-3.6/lib.cxx:28465)
> File "pyarrow/error.pxi", line 98, in pyarrow.lib.check_status
> (/arrow/python/build/temp.linux-x86_64-3.6/lib.cxx:9068)
> pyarrow.lib.ArrowException: Unknown error: an integer is required (got type
> str)
> {code}
> Same problem with other special decimal values like {{infinity}}.
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