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nyalldawsonnyalldawson
committedMar 5, 2023
[expressions][feature] Add ltrim/rtrim functions
Allows trimming spaces or other characters from just the start or end of strings
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ltr-3_40final-3_32_0
1 parent 12d6b44 commit 3c91c62

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‎resources/function_help/json/ltrim

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{
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"name": "ltrim",
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"type": "function",
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"groups": ["String"],
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"description": "Removes the longest string containing only the specified characters (a space by default) from the start of string.",
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"arguments": [{
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"arg": "string",
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"description": "string to trim"
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},
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{
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"arg": "characters",
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"description": "characters to trim",
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"optional": true,
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"default": "' '"
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}],
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"examples": [{
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"expression": "ltrim(' hello world ')",
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"returns": "'hello world '"
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},
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{
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"expression": "ltrim('zzzytest', 'xyz')",
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"returns": "'test'"
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}],
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"tags": ["removes", "leading", "whitespace", "spaces", "tabs"]
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}

‎resources/function_help/json/rtrim

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{
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"name": "rtrim",
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"type": "function",
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"groups": ["String"],
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"description": "Removes the longest string containing only the specified characters (a space by default) from the end of string.",
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"arguments": [{
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"arg": "string",
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"description": "string to trim"
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},
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{
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"arg": "characters",
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"description": "characters to trim",
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"optional": true,
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"default": "' '"
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}],
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"examples": [{
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"expression": "rtrim(' hello world ')",
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"returns": "' hello world'"
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},
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{
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"expression": "rtrim('testxxzx', 'xyz')",
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"returns": "'test'"
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}],
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"tags": ["removes", "whitespace", "spaces", "tabs", "trailing"]
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}

‎src/core/expression/qgsexpressionfunction.cpp

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@@ -1342,6 +1342,28 @@ static QVariant fcnTrim( const QVariantList &values, const QgsExpressionContext
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return QVariant( str.trimmed() );
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}
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static QVariant fcnLTrim( const QVariantList &values, const QgsExpressionContext *, QgsExpression *parent, const QgsExpressionNodeFunction * )
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{
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QString str = QgsExpressionUtils::getStringValue( values.at( 0 ), parent );
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const QString characters = QgsExpressionUtils::getStringValue( values.at( 1 ), parent );
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const QRegularExpression re( QStringLiteral( "^([%1]*)" ).arg( QRegularExpression::escape( characters ) ) );
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str.replace( re, QString() );
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return QVariant( str );
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}
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static QVariant fcnRTrim( const QVariantList &values, const QgsExpressionContext *, QgsExpression *parent, const QgsExpressionNodeFunction * )
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{
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QString str = QgsExpressionUtils::getStringValue( values.at( 0 ), parent );
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const QString characters = QgsExpressionUtils::getStringValue( values.at( 1 ), parent );
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const QRegularExpression re( QStringLiteral( "([%1]*)$" ).arg( QRegularExpression::escape( characters ) ) );
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str.replace( re, QString() );
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return QVariant( str );
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}
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static QVariant fcnLevenshtein( const QVariantList &values, const QgsExpressionContext *, QgsExpression *parent, const QgsExpressionNodeFunction * )
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{
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QString string1 = QgsExpressionUtils::getStringValue( values.at( 0 ), parent );
@@ -8159,6 +8181,12 @@ const QList<QgsExpressionFunction *> &QgsExpression::Functions()
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<< new QgsStaticExpressionFunction( QStringLiteral( "upper" ), QgsExpressionFunction::ParameterList() << QgsExpressionFunction::Parameter( QStringLiteral( "string" ) ), fcnUpper, QStringLiteral( "String" ) )
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<< new QgsStaticExpressionFunction( QStringLiteral( "title" ), QgsExpressionFunction::ParameterList() << QgsExpressionFunction::Parameter( QStringLiteral( "string" ) ), fcnTitle, QStringLiteral( "String" ) )
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<< new QgsStaticExpressionFunction( QStringLiteral( "trim" ), QgsExpressionFunction::ParameterList() << QgsExpressionFunction::Parameter( QStringLiteral( "string" ) ), fcnTrim, QStringLiteral( "String" ) )
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<< new QgsStaticExpressionFunction( QStringLiteral( "ltrim" ), QgsExpressionFunction::ParameterList()
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<< QgsExpressionFunction::Parameter( QStringLiteral( "string" ) )
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<< QgsExpressionFunction::Parameter( QStringLiteral( "characters" ), true, QStringLiteral( " " ) ), fcnLTrim, QStringLiteral( "String" ) )
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<< new QgsStaticExpressionFunction( QStringLiteral( "rtrim" ), QgsExpressionFunction::ParameterList()
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<< QgsExpressionFunction::Parameter( QStringLiteral( "string" ) )
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<< QgsExpressionFunction::Parameter( QStringLiteral( "characters" ), true, QStringLiteral( " " ) ), fcnRTrim, QStringLiteral( "String" ) )
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<< new QgsStaticExpressionFunction( QStringLiteral( "levenshtein" ), QgsExpressionFunction::ParameterList() << QgsExpressionFunction::Parameter( QStringLiteral( "string1" ) ) << QgsExpressionFunction::Parameter( QStringLiteral( "string2" ) ), fcnLevenshtein, QStringLiteral( "Fuzzy Matching" ) )
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<< new QgsStaticExpressionFunction( QStringLiteral( "longest_common_substring" ), QgsExpressionFunction::ParameterList() << QgsExpressionFunction::Parameter( QStringLiteral( "string1" ) ) << QgsExpressionFunction::Parameter( QStringLiteral( "string2" ) ), fcnLCS, QStringLiteral( "Fuzzy Matching" ) )
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<< new QgsStaticExpressionFunction( QStringLiteral( "hamming_distance" ), QgsExpressionFunction::ParameterList() << QgsExpressionFunction::Parameter( QStringLiteral( "string1" ) ) << QgsExpressionFunction::Parameter( QStringLiteral( "string2" ) ), fcnHamming, QStringLiteral( "Fuzzy Matching" ) )

‎tests/src/core/testqgsexpression.cpp

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@@ -1678,6 +1678,20 @@ class TestQgsExpression: public QObject
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QTest::newRow( "title" ) << "title(' HeLlO WORLD ')" << false << QVariant( " Hello World " );
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QTest::newRow( "trim" ) << "trim(' Test String ')" << false << QVariant( "Test String" );
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QTest::newRow( "trim empty string" ) << "trim('')" << false << QVariant( "" );
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QTest::newRow( "ltrim none" ) << "ltrim('trim ')" << false << QVariant( "trim " );
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QTest::newRow( "ltrim space" ) << "ltrim(' trim ')" << false << QVariant( "trim " );
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QTest::newRow( "ltrim empty string" ) << "ltrim('')" << false << QVariant( "" );
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QTest::newRow( "ltrim('zzzytrim', 'xyz')" ) << "ltrim('zzzytrim', 'xyz')" << false << QVariant( "trim" );
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QTest::newRow( "ltrim('zzzytrim', 'a')" ) << "ltrim('zzzytrim', 'a')" << false << QVariant( "zzzytrim" );
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QTest::newRow( "ltrim('zzzytrim', '[(*')" ) << "ltrim('zzzytrim', '[(*')" << false << QVariant( "zzzytrim" );
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QTest::newRow( "ltrim('))(* *[[trim', '[())* ')" ) << "ltrim('))(* *[[trim', '[())* ')" << false << QVariant( "trim" );
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QTest::newRow( "rtrim none" ) << "rtrim(' trim')" << false << QVariant( " trim" );
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QTest::newRow( "rtrim space" ) << "rtrim(' trim ')" << false << QVariant( " trim" );
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QTest::newRow( "rtrim empty string" ) << "rtrim('')" << false << QVariant( "" );
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QTest::newRow( "rtrim('trimzzzy', 'xyz')" ) << "rtrim('trimzzzy', 'xyz')" << false << QVariant( "trim" );
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QTest::newRow( "rtrim('trimzzzy', 'a')" ) << "rtrim('trimzzzy', 'a')" << false << QVariant( "trimzzzy" );
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QTest::newRow( "rtrim('trimzzzy', '[(*')" ) << "rtrim('trimzzzy', '[(*')" << false << QVariant( "trimzzzy" );
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QTest::newRow( "rtrim('trim)(* *[[', '[()* ')" ) << "rtrim('trim)(* *[[', '[()* ')" << false << QVariant( "trim" );
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QTest::newRow( "char" ) << "char(81)" << false << QVariant( "Q" );
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QTest::newRow( "ascii single letter" ) << "ascii('Q')" << false << QVariant( 81 );
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QTest::newRow( "ascii word" ) << "ascii('QGIS')" << false << QVariant( 81 );

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