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Update range function to follow Python's range function

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Joanne 2018-02-15 16:19:12 +08:00 committed by Antonin Delpeuch
parent e2793daf54
commit 35c991d9c2
1 changed files with 202 additions and 122 deletions
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284
main/src/com/google/refine/expr/functions/strings/Range.java
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@ -4,7 +4,6 @@ import java.util.regex.Matcher;
import java.util.regex.Pattern;
import java.util.Properties;
import org.apache.commons.lang3.StringUtils;
import org.json.JSONException;
import org.json.JSONWriter;
@ -16,32 +15,31 @@ import com.google.refine.grel.Function;
* Implements the logic behind the range function.
*
* The range function can take in a single string of the form 'a, b, c' or three
* integers a, b, c where a and b represents the first and last numbers in the range respectively.
*
* If b is not given, a defaults to the range end and 0 becomes the range start.
* c is optional and represents the step (increment) for the generated sequence.
* integers a, b, c where a and b represents the first (inclusive) and last (exclusive)
* numbers in the range respectively. If b is not given, a defaults to the range end
* and 0 becomes the range start. c is optional and represents the step (increment)
* for the generated sequence.
*/
public class Range implements Function {
private static final int STRING_ARG_LENGTH = 1;
private static final String SEPARATOR = ",";
private static final int INTEGER_ARGS_LENGTH = 2;
private static final int INTEGER_ARGS_WITH_STEP = 3;
private static final String DEFAULT_RANGE_START = "0";
private static final String lastCharacterCommaRegex = ",$";
private static final Pattern lastCharacterCommaPattern = Pattern.compile(lastCharacterCommaRegex);
private static final int DEFAULT_START = 0;
private static final int DEFAULT_STEP = 1;
private static final String[] EMPTY_STRING_ARRAY = new String[0];
@Override
public Object call(Properties bindings, Object[] args) {
if (args.length == STRING_ARG_LENGTH) {
if (args.length == 1) {
return createRangeWithOneGivenArgument(args);
} else if (args.length == INTEGER_ARGS_LENGTH) {
} else if (args.length == 2) {
return createRangeWithTwoGivenArguments(args);
} else if (args.length == INTEGER_ARGS_WITH_STEP) {
} else if (args.length == 3) {
return createRangeWithThreeGivenArguments(args);
}
@ -53,7 +51,7 @@ public class Range implements Function {
/**
* Checks if a given string has a comma as the last character.
*
* This is primarily used against abusing the range function like doing range("1,").
* This is primarily used to detect edge cases like doing range("1,").
*/
private boolean hasCommaAsLastCharacter(String test) {
Matcher lastCharacterCommaMatcher = lastCharacterCommaPattern.matcher(test);
@ -61,52 +59,72 @@ public class Range implements Function {
}
/**
* Processes the single argument given to determine if the argument is a valid string, a
* valid integer, or an invalid argument.
* Processes the single argument given to determine if the argument is (i) a valid string, (ii) a
* valid integer, or (iii) an invalid argument.
*
* If the argument is a valid string, it can either be in the form 'a', or 'a, b' or 'a, b, c'
* where a and b are the start and end of the range respectively, and c is the optional
* step argument. In the case where 'a' is the only argument, 'a' becomes the range end and
* 0 becomes the default range start.
* step argument. In the case where 'a' is the only argument, 'a' becomes the range end (exclusive)
* and 0 becomes the default range start.
*
* If the argument is a valid integer, it can will default to become the range end, and 0 defaults
* to become the range start.
*
* In all other cases, the argument is considered invalid.
*/
private Object createRangeWithOneGivenArgument(Object[] args) {
Object range = args[0];
int rangeStart = DEFAULT_START;
int rangeEnd = 0;
int rangeStep = DEFAULT_STEP;
// Check for valid string argument(s)
if (range != null && range instanceof String) {
String rangeString = ((String) range).trim();
String[] rangeValues = rangeString.split(SEPARATOR);
if (rangeValues.length == 1 && StringUtils.isNumeric(rangeValues[0])
&& !hasCommaAsLastCharacter(rangeString)) {
String rangeEnd = rangeValues[0].trim();
if (hasCommaAsLastCharacter(rangeString)) {
return new EvalError("the last character in the input string should not be a comma");
}
return createRange(DEFAULT_RANGE_START, rangeEnd);
} else if (rangeValues.length == INTEGER_ARGS_LENGTH) {
String rangeStart = rangeValues[0].trim();
String rangeEnd = rangeValues[1].trim();
if (StringUtils.isNumeric(rangeStart) && StringUtils.isNumeric(rangeEnd)) {
return createRange(rangeStart, rangeEnd);
}
} else if (rangeValues.length == INTEGER_ARGS_WITH_STEP) {
String rangeStart = rangeValues[0].trim();
String rangeEnd = rangeValues[1].trim();
String rangeStep = rangeValues[2].trim();
if (StringUtils.isNumeric(rangeStart) && StringUtils.isNumeric(rangeEnd)
&& StringUtils.isNumeric(rangeStep)) {
try {
if (rangeValues.length == 1) {
rangeEnd = Integer.parseInt(rangeValues[0].trim());
return createRange(rangeStart, rangeEnd, rangeStep);
} else if (rangeValues.length == 2) {
rangeStart = Integer.parseInt(rangeValues[0].trim());
rangeEnd = Integer.parseInt(rangeValues[1].trim());
return createRange(rangeStart, rangeEnd, rangeStep);
} else if (rangeValues.length == 3) {
rangeStart = Integer.parseInt(rangeValues[0].trim());
rangeEnd = Integer.parseInt(rangeValues[1].trim());
rangeStep = Integer.parseInt(rangeValues[2].trim());
return createRange(rangeStart, rangeEnd, rangeStep);
}
} catch (NumberFormatException nfe) {
return new EvalError(ControlFunctionRegistry.getFunctionName(this)
+ " expects a string of the form 'a, b, c' or integers a, b, c where a and b "
+ "are the start and the end of the range respectively and c is the step (increment)");
}
}
if (range != null && StringUtils.isNumeric(range.toString())) {
String rangeEnd = range.toString();
// Check for valid negative integer argument
if (range != null && range instanceof Double && (Double) range % 1 == 0) {
range = ((Double) range).intValue();
return createRange(DEFAULT_START, rangeEnd, DEFAULT_STEP);
}
return createRange(DEFAULT_RANGE_START, rangeEnd);
// Check for valid positive integer argument
if (range != null) {
try {
rangeEnd = Integer.parseInt(String.valueOf(range));
return createRange(DEFAULT_START, rangeEnd, DEFAULT_STEP);
} catch (NumberFormatException nfe) {
return new EvalError(ControlFunctionRegistry.getFunctionName(this)
+ " expects a string of the form 'a, b, c' or integers a, b, c where a and b "
+ "are the start and the end of the range respectively and c is the step (increment)");
}
}
return new EvalError(ControlFunctionRegistry.getFunctionName(this)
@ -115,56 +133,101 @@ public class Range implements Function {
}
/**
* Processes the two arguments given to determine if the arguments are two valid integers or
* a valid string and step or invalid arguments.
* Processes the two arguments given to determine if the arguments are (i) two valid strings,
* (ii) two valid integers or (iii) a valid string and an integer or (iv) invalid arguments.
*
* If the arguments are valid strings, the strings can either be such that (i) each string contains
* single arguments (i.e. two arguments in total), or (ii) one string contains one argument and the other
* string contains two argument (i.e. three arguments in total).
*
* If the arguments are a valid string and a valid integer, the string can be such that (i) the string
* contains a single argument (i.e. two arguments in total) or (ii) the string contains two arguments
* (i.e. three arguments in total).
*
* In all other cases, the arguments are considered invalid.
*/
private Object createRangeWithTwoGivenArguments(Object[] args) {
String rangeStart = args[0].toString().trim();
String rangeEnd = args[1].toString().trim();
Object firstArg = args[0];
Object secondArg = args[1];
String range = rangeStart;
String rangeStep = rangeEnd;
int rangeStart = DEFAULT_START;
int rangeEnd = 0;
int rangeStep = DEFAULT_STEP;
boolean isTwoValidIntegers = false;
boolean isValidStringWithStep = false;
String[] rangeValues = range.split(SEPARATOR);
if (rangeValues.length == 1) {
isTwoValidIntegers = true;
} else if (rangeValues.length == 2) {
isValidStringWithStep = true;
if (firstArg == null || secondArg == null) {
return new EvalError(ControlFunctionRegistry.getFunctionName(this)
+ " expects a string of the form 'a, b, c' or integers a, b, c where a and b "
+ "are the start and the end of the range respectively and c is the step (increment)");
}
if (isTwoValidIntegers && StringUtils.isNumeric(rangeStart) &&
StringUtils.isNumeric(rangeEnd)) {
return createRange(rangeStart, rangeEnd);
} else if (isValidStringWithStep) {
rangeStart = rangeValues[0].trim();
rangeEnd = rangeValues[1].trim();
boolean hasString = false;
boolean hasTwoIntegers = true;
if (StringUtils.isNumeric(rangeStart) && StringUtils.isNumeric(rangeEnd)
&& StringUtils.isNumeric(rangeStep)) {
return createRange(rangeStart, rangeEnd, rangeStep);
if (firstArg instanceof String || secondArg instanceof String) {
hasString = true;
hasTwoIntegers = false;
}
boolean hasTwoArguments = hasTwoIntegers;
boolean hasThreeArguments = false;
// Deal with valid negative integers
if (firstArg instanceof Double && (Double) firstArg % 1 == 0) {
firstArg = ((Double) firstArg).intValue();
}
if (secondArg instanceof Double && (Double) secondArg % 1 == 0) {
secondArg = ((Double) secondArg).intValue();
}
String firstArgStringified = String.valueOf(firstArg).trim();
String secondArgStringified = String.valueOf(secondArg).trim();
String thirdArgStringified = "";
if (hasCommaAsLastCharacter(firstArgStringified) || hasCommaAsLastCharacter(secondArgStringified)) {
return new EvalError("the last character in the input string should not be a comma");
}
// Check if the strings are valid strings (e.g. range("1, 2", "3, 4") should fail but
// range("1, 2", "1") should pass)
if (hasString) {
String[] firstArgArray = firstArgStringified.split(SEPARATOR);
String[] secondArgArray = secondArgStringified.split(SEPARATOR);
int combinedArrayLength = firstArgArray.length + secondArgArray.length;
if (combinedArrayLength == 3) {
hasThreeArguments = true;
if (firstArgArray.length == 1) {
secondArgStringified = secondArgArray[0].trim();
thirdArgStringified = secondArgArray[1].trim();
} else {
firstArgStringified = firstArgArray[0].trim();
secondArgStringified = firstArgArray[1].trim();
thirdArgStringified = secondArgArray[0].trim();
}
} else if (combinedArrayLength == 2) {
hasTwoArguments = true;
}
}
return new EvalError(ControlFunctionRegistry.getFunctionName(this)
+ " expects a string of the form 'a, b, c' or integers a, b, c where a and b "
+ "are the start and the end of the range respectively and c is the step (increment)");
}
/**
* Processes the three arguments given to determine if the arguments are three valid integers or
* invalid arguments.
*/
private Object createRangeWithThreeGivenArguments(Object[] args) {
String rangeStart = args[0].toString().trim();
String rangeEnd = args[1].toString().trim();
String rangeStep = args[2].toString().trim();
if (StringUtils.isNumeric(rangeStart) && StringUtils.isNumeric(rangeEnd)
&& StringUtils.isNumeric(rangeStep)) {
return createRange(rangeStart, rangeEnd, rangeStep);
try {
if (hasTwoArguments) {
rangeStart = Integer.parseInt(firstArgStringified);
rangeEnd = Integer.parseInt(secondArgStringified);
return createRange(rangeStart, rangeEnd, rangeStep);
} else if (hasThreeArguments) {
rangeStart = Integer.parseInt(firstArgStringified);
rangeEnd = Integer.parseInt(secondArgStringified);
rangeStep = Integer.parseInt(thirdArgStringified);
return createRange(rangeStart, rangeEnd, rangeStep);
}
} catch (NumberFormatException nfe) {
return new EvalError(ControlFunctionRegistry.getFunctionName(this)
+ " expects a string of the form 'a, b, c' or integers a, b, c where a and b "
+ "are the start and the end of the range respectively and c is the step (increment)");
}
return new EvalError(ControlFunctionRegistry.getFunctionName(this)
@ -173,13 +236,40 @@ public class Range implements Function {
}
/**
* Creates a range from the given range values.
* Processes the three arguments given to determine if the arguments are (i) three valid strings,
* (ii) three valid integers, (iii) two valid strings and a valid integer, (iv) a valid string and
* two valid integers or (v) invalid arguments.
*
* The generated range is either an increasing sequence or a decreasing sequence, and
* each number in the sequence differs from the next number by one.
* In this case, all valid strings can only contain a single argument.
*/
private static Object createRange(String rangeStart, String rangeEnd) {
return createRange(rangeStart, rangeEnd, "1");
private Object createRangeWithThreeGivenArguments(Object[] args) {
Object firstArg = args[0];
Object secondArg = args[1];
Object thirdArg = args[2];
// Deal with negative integers first
if (firstArg != null && firstArg instanceof Double && (Double) firstArg % 1 == 0) {
firstArg = ((Double) firstArg).intValue();
}
if (secondArg != null && secondArg instanceof Double && (Double) secondArg % 1 == 0) {
secondArg = ((Double) secondArg).intValue();
}
if (thirdArg != null && thirdArg instanceof Double && (Double) thirdArg % 1 == 0) {
thirdArg = ((Double) thirdArg).intValue();
}
try {
int rangeStart = Integer.parseInt(String.valueOf(firstArg).trim());
int rangeEnd = Integer.parseInt(String.valueOf(secondArg).trim());
int rangeStep = Integer.parseInt(String.valueOf(thirdArg).trim());
return createRange(rangeStart, rangeEnd, rangeStep);
} catch (NumberFormatException nfe) {
return new EvalError(ControlFunctionRegistry.getFunctionName(this)
+ " expects a string of the form 'a, b, c' or integers a, b, c where a and b "
+ "are the start and the end of the range respectively and c is the step (increment)");
}
}
/**
@ -188,27 +278,17 @@ public class Range implements Function {
* The generated range is either an increasing sequence or a decreasing sequence, and
* each number in the sequence differs from the next number by the step value.
*/
private static Object createRange(String rangeStart, String rangeEnd, String rangeStep) {
int start = Integer.parseInt(rangeStart);
int end = Integer.parseInt(rangeEnd);
int step = Integer.parseInt(rangeStep);
int negativeStep = -step;
int rangeSize = 0;
if (step != 0) {
rangeSize = (int) (Math.ceil((double) (Math.abs(start - end) + 1)/ step));
private static Object createRange(int start, int stop, int step) {
if ((start > stop && step > 0) || (start < stop && step < 0) || step == 0) {
return EMPTY_STRING_ARRAY;
}
int rangeSize = (int) (Math.ceil(((double) Math.abs(start - stop))/ Math.abs(step)));
String[] generatedRange = new String[rangeSize];
if (start < end) {
for (int i = 0; i < rangeSize; i++) {
generatedRange[i] = Integer.toString(start + step * i);
}
} else {
for (int i = 0; i < rangeSize; i++) {
generatedRange[i] = Integer.toString(start + negativeStep * i);
}
for (int i = 0; i < rangeSize; i++) {
generatedRange[i] = Integer.toString(start + step * i);
}
return generatedRange;