How to add space before and after contional operator in string?

I have the string e.g "number1<=number2&&number3>number4||number2=number4" and having operator list as -

var operators = new List<string> {"=", "!", "<", ">", ">=", "<=", "!=","||","&&"};

So expectation is need to introduce single space before and after the operator in string.

"number1 <= number2 && number3 > number4 || number2 = number4"

I have tried following option but its not working in case of eg. <, >=

    public static string AddSpaceBeforeAndAfterOperator(string expression)

    {

                var operators = new List<string> {"=", "!", "<", ">", ">=", "<=", "!=", "||", "&&"};

                foreach (var op in operators)

                {

                    var index = expression.IndexOf(op, StringComparison.Ordinal);

                    if (index >= 0)

                    {

                        if (expression.Substring(index - 1) != " ")

                        {

                            expression = expression.Insert(index-1, " ");

                        }



                        expression = expression.Insert(index + op.Length + 1, " ");

                    }

                }



                return expression;

}

Note: Operator list is coming as random.

Any help appreciated!

asked Nov 15 '18 at 6:39

Sumit Deshpande

1,62611326

You could construct a regex by "(" + string.Join("|", operators.Select(Regex.Escape)) + ")" and then doing a regex.Replace

– Klaus Gütter
Nov 15 '18 at 6:45

add a comment |

I have the string e.g "number1<=number2&&number3>number4||number2=number4" and having operator list as -

var operators = new List<string> {"=", "!", "<", ">", ">=", "<=", "!=","||","&&"};

So expectation is need to introduce single space before and after the operator in string.

"number1 <= number2 && number3 > number4 || number2 = number4"

I have tried following option but its not working in case of eg. <, >=

    public static string AddSpaceBeforeAndAfterOperator(string expression)

    {

                var operators = new List<string> {"=", "!", "<", ">", ">=", "<=", "!=", "||", "&&"};

                foreach (var op in operators)

                {

                    var index = expression.IndexOf(op, StringComparison.Ordinal);

                    if (index >= 0)

                    {

                        if (expression.Substring(index - 1) != " ")

                        {

                            expression = expression.Insert(index-1, " ");

                        }



                        expression = expression.Insert(index + op.Length + 1, " ");

                    }

                }



                return expression;

}

Note: Operator list is coming as random.

Any help appreciated!

asked Nov 15 '18 at 6:39

Sumit Deshpande

1,62611326

You could construct a regex by "(" + string.Join("|", operators.Select(Regex.Escape)) + ")" and then doing a regex.Replace

– Klaus Gütter
Nov 15 '18 at 6:45

add a comment |

I have the string e.g "number1<=number2&&number3>number4||number2=number4" and having operator list as -

var operators = new List<string> {"=", "!", "<", ">", ">=", "<=", "!=","||","&&"};

So expectation is need to introduce single space before and after the operator in string.

"number1 <= number2 && number3 > number4 || number2 = number4"

I have tried following option but its not working in case of eg. <, >=

    public static string AddSpaceBeforeAndAfterOperator(string expression)

    {

                var operators = new List<string> {"=", "!", "<", ">", ">=", "<=", "!=", "||", "&&"};

                foreach (var op in operators)

                {

                    var index = expression.IndexOf(op, StringComparison.Ordinal);

                    if (index >= 0)

                    {

                        if (expression.Substring(index - 1) != " ")

                        {

                            expression = expression.Insert(index-1, " ");

                        }



                        expression = expression.Insert(index + op.Length + 1, " ");

                    }

                }



                return expression;

}

Note: Operator list is coming as random.

Any help appreciated!

asked Nov 15 '18 at 6:39

Sumit Deshpande

1,62611326

I have the string e.g "number1<=number2&&number3>number4||number2=number4" and having operator list as -

var operators = new List<string> {"=", "!", "<", ">", ">=", "<=", "!=","||","&&"};

So expectation is need to introduce single space before and after the operator in string.

"number1 <= number2 && number3 > number4 || number2 = number4"

I have tried following option but its not working in case of eg. <, >=

    public static string AddSpaceBeforeAndAfterOperator(string expression)

    {

                var operators = new List<string> {"=", "!", "<", ">", ">=", "<=", "!=", "||", "&&"};

                foreach (var op in operators)

                {

                    var index = expression.IndexOf(op, StringComparison.Ordinal);

                    if (index >= 0)

                    {

                        if (expression.Substring(index - 1) != " ")

                        {

                            expression = expression.Insert(index-1, " ");

                        }



                        expression = expression.Insert(index + op.Length + 1, " ");

                    }

                }



                return expression;

}

Note: Operator list is coming as random.

Any help appreciated!

c# string c#-4.0

asked Nov 15 '18 at 6:39

Sumit Deshpande

1,62611326

asked Nov 15 '18 at 6:39

Sumit Deshpande

1,62611326

asked Nov 15 '18 at 6:39

Sumit Deshpande

1,62611326

asked Nov 15 '18 at 6:39

Sumit Deshpande

1,62611326

asked Nov 15 '18 at 6:39

Sumit Deshpande

1,62611326

You could construct a regex by "(" + string.Join("|", operators.Select(Regex.Escape)) + ")" and then doing a regex.Replace

– Klaus Gütter
Nov 15 '18 at 6:45

add a comment |

You could construct a regex by "(" + string.Join("|", operators.Select(Regex.Escape)) + ")" and then doing a regex.Replace

– Klaus Gütter
Nov 15 '18 at 6:45

You could construct a regex by "(" + string.Join("|", operators.Select(Regex.Escape)) + ")" and then doing a regex.Replace

– Klaus Gütter
Nov 15 '18 at 6:45

add a comment |

2 Answers
2

active

oldest

votes

I would recommend a regex solution.

First, you need to escape all your operators, join them together with |:

var operatorsString = string.Join("|", 

    operators.OrderByDescending(x => x.Length).Select(Regex.Escape).ToArray()

);

// OrderByDescending here because we want the longer operators to be matched first.

Next, create the regex:

var regex = $"\s*({operatorString})\s*";

Using the operators array in the question, the array looks like this:

s*(<=|>=|!=|==||||&&|=|!|<|>)s?*

Note that s* is used to check if the operator is already surrounded by spaces. If it is, those spaces will be matched and replaced.

The replacement is:

$1

Code:

Regex.Replace(input, regex, " $1 ");

Note the leading and trailing space.

Also note that Regex is inside the System.Text.RegularExpressions namespace.

Demo

edited Nov 15 '18 at 8:20

answered Nov 15 '18 at 6:54

Sweeper

68.8k1073140

Probably, a better choice s* instead of s? for "if the operator is already surrounded by spaces" (what if we have several spaces: "a___>=__b"?)

– Dmitry Bychenko
Nov 15 '18 at 7:55

@DmitryBychenko Good point. Edited.

– Sweeper
Nov 15 '18 at 8:21

@Sweeper - Thanks for the suggestion.

– Sumit Deshpande
Nov 16 '18 at 5:14

add a comment |

Im not sure if this is the most effective way to do this, but is is rally simple by using replace

public static string AddSpaceBeforeAndAfterOperator(string expression)

{

    var operators = new List<string> { "=", "!", "<", ">", ">=", "<=", "!=", "||", "&&" };

    foreach (var op in operators)

    {

        expression = expression.Replace(op, " " + op + " ");

    }



    return expression;

 }

answered Nov 15 '18 at 6:47

Daniel W.

226111

2

Thanks for the suggestion, But this is not going to work in case of a scenario like "number1<=number2" it will end up returning "number1 < = number2" which is not correct

– Sumit Deshpande
Nov 15 '18 at 6:52

wont work for <= will result < =

– styx
Nov 15 '18 at 6:53

add a comment |

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2 Answers
2

active

oldest

votes

2 Answers
2

active

oldest

votes

I would recommend a regex solution.

First, you need to escape all your operators, join them together with |:

var operatorsString = string.Join("|", 

    operators.OrderByDescending(x => x.Length).Select(Regex.Escape).ToArray()

);

// OrderByDescending here because we want the longer operators to be matched first.

Next, create the regex:

var regex = $"\s*({operatorString})\s*";

Using the operators array in the question, the array looks like this:

s*(<=|>=|!=|==||||&&|=|!|<|>)s?*

Note that s* is used to check if the operator is already surrounded by spaces. If it is, those spaces will be matched and replaced.

The replacement is:

$1

Code:

Regex.Replace(input, regex, " $1 ");

Note the leading and trailing space.

Also note that Regex is inside the System.Text.RegularExpressions namespace.

Demo

edited Nov 15 '18 at 8:20

answered Nov 15 '18 at 6:54

Sweeper

68.8k1073140

Probably, a better choice s* instead of s? for "if the operator is already surrounded by spaces" (what if we have several spaces: "a___>=__b"?)

– Dmitry Bychenko
Nov 15 '18 at 7:55

@DmitryBychenko Good point. Edited.

– Sweeper
Nov 15 '18 at 8:21

@Sweeper - Thanks for the suggestion.

– Sumit Deshpande
Nov 16 '18 at 5:14

add a comment |

I would recommend a regex solution.

First, you need to escape all your operators, join them together with |:

var operatorsString = string.Join("|", 

    operators.OrderByDescending(x => x.Length).Select(Regex.Escape).ToArray()

);

// OrderByDescending here because we want the longer operators to be matched first.

Next, create the regex:

var regex = $"\s*({operatorString})\s*";

Using the operators array in the question, the array looks like this:

s*(<=|>=|!=|==||||&&|=|!|<|>)s?*

Note that s* is used to check if the operator is already surrounded by spaces. If it is, those spaces will be matched and replaced.

The replacement is:

$1

Code:

Regex.Replace(input, regex, " $1 ");

Note the leading and trailing space.

Also note that Regex is inside the System.Text.RegularExpressions namespace.

Demo

edited Nov 15 '18 at 8:20

answered Nov 15 '18 at 6:54

Sweeper

68.8k1073140

Probably, a better choice s* instead of s? for "if the operator is already surrounded by spaces" (what if we have several spaces: "a___>=__b"?)

– Dmitry Bychenko
Nov 15 '18 at 7:55

@DmitryBychenko Good point. Edited.

– Sweeper
Nov 15 '18 at 8:21

@Sweeper - Thanks for the suggestion.

– Sumit Deshpande
Nov 16 '18 at 5:14

add a comment |

I would recommend a regex solution.

First, you need to escape all your operators, join them together with |:

var operatorsString = string.Join("|", 

    operators.OrderByDescending(x => x.Length).Select(Regex.Escape).ToArray()

);

// OrderByDescending here because we want the longer operators to be matched first.

Next, create the regex:

var regex = $"\s*({operatorString})\s*";

Using the operators array in the question, the array looks like this:

s*(<=|>=|!=|==||||&&|=|!|<|>)s?*

Note that s* is used to check if the operator is already surrounded by spaces. If it is, those spaces will be matched and replaced.

The replacement is:

$1

Code:

Regex.Replace(input, regex, " $1 ");

Note the leading and trailing space.

Also note that Regex is inside the System.Text.RegularExpressions namespace.

Demo

edited Nov 15 '18 at 8:20

answered Nov 15 '18 at 6:54

Sweeper

68.8k1073140

I would recommend a regex solution.

First, you need to escape all your operators, join them together with |:

var operatorsString = string.Join("|", 

    operators.OrderByDescending(x => x.Length).Select(Regex.Escape).ToArray()

);

// OrderByDescending here because we want the longer operators to be matched first.

Next, create the regex:

var regex = $"\s*({operatorString})\s*";

Using the operators array in the question, the array looks like this:

s*(<=|>=|!=|==||||&&|=|!|<|>)s?*

Note that s* is used to check if the operator is already surrounded by spaces. If it is, those spaces will be matched and replaced.

The replacement is:

$1

Code:

Regex.Replace(input, regex, " $1 ");

Note the leading and trailing space.

Also note that Regex is inside the System.Text.RegularExpressions namespace.

Demo

edited Nov 15 '18 at 8:20

answered Nov 15 '18 at 6:54

Sweeper

68.8k1073140

edited Nov 15 '18 at 8:20

answered Nov 15 '18 at 6:54

Sweeper

68.8k1073140

answered Nov 15 '18 at 6:54

Sweeper

68.8k1073140

answered Nov 15 '18 at 6:54

Sweeper

68.8k1073140

Probably, a better choice s* instead of s? for "if the operator is already surrounded by spaces" (what if we have several spaces: "a___>=__b"?)

– Dmitry Bychenko
Nov 15 '18 at 7:55

@DmitryBychenko Good point. Edited.

– Sweeper
Nov 15 '18 at 8:21

@Sweeper - Thanks for the suggestion.

– Sumit Deshpande
Nov 16 '18 at 5:14

add a comment |

Probably, a better choice s* instead of s? for "if the operator is already surrounded by spaces" (what if we have several spaces: "a___>=__b"?)

– Dmitry Bychenko
Nov 15 '18 at 7:55

@DmitryBychenko Good point. Edited.

– Sweeper
Nov 15 '18 at 8:21

@Sweeper - Thanks for the suggestion.

– Sumit Deshpande
Nov 16 '18 at 5:14

Probably, a better choice s* instead of s? for "if the operator is already surrounded by spaces" (what if we have several spaces: "a___>=__b"?)

– Dmitry Bychenko
Nov 15 '18 at 7:55

@DmitryBychenko Good point. Edited.

– Sweeper
Nov 15 '18 at 8:21

@Sweeper - Thanks for the suggestion.

– Sumit Deshpande
Nov 16 '18 at 5:14

add a comment |

Im not sure if this is the most effective way to do this, but is is rally simple by using replace

public static string AddSpaceBeforeAndAfterOperator(string expression)

{

    var operators = new List<string> { "=", "!", "<", ">", ">=", "<=", "!=", "||", "&&" };

    foreach (var op in operators)

    {

        expression = expression.Replace(op, " " + op + " ");

    }



    return expression;

 }

answered Nov 15 '18 at 6:47

Daniel W.

226111

2

Thanks for the suggestion, But this is not going to work in case of a scenario like "number1<=number2" it will end up returning "number1 < = number2" which is not correct

– Sumit Deshpande
Nov 15 '18 at 6:52

wont work for <= will result < =

– styx
Nov 15 '18 at 6:53

add a comment |

Im not sure if this is the most effective way to do this, but is is rally simple by using replace

public static string AddSpaceBeforeAndAfterOperator(string expression)

{

    var operators = new List<string> { "=", "!", "<", ">", ">=", "<=", "!=", "||", "&&" };

    foreach (var op in operators)

    {

        expression = expression.Replace(op, " " + op + " ");

    }



    return expression;

 }

answered Nov 15 '18 at 6:47

Daniel W.

226111

2

Thanks for the suggestion, But this is not going to work in case of a scenario like "number1<=number2" it will end up returning "number1 < = number2" which is not correct

– Sumit Deshpande
Nov 15 '18 at 6:52

wont work for <= will result < =

– styx
Nov 15 '18 at 6:53

add a comment |

Im not sure if this is the most effective way to do this, but is is rally simple by using replace

public static string AddSpaceBeforeAndAfterOperator(string expression)

{

    var operators = new List<string> { "=", "!", "<", ">", ">=", "<=", "!=", "||", "&&" };

    foreach (var op in operators)

    {

        expression = expression.Replace(op, " " + op + " ");

    }



    return expression;

 }

answered Nov 15 '18 at 6:47

Daniel W.

226111

Im not sure if this is the most effective way to do this, but is is rally simple by using replace

public static string AddSpaceBeforeAndAfterOperator(string expression)

{

    var operators = new List<string> { "=", "!", "<", ">", ">=", "<=", "!=", "||", "&&" };

    foreach (var op in operators)

    {

        expression = expression.Replace(op, " " + op + " ");

    }



    return expression;

 }

answered Nov 15 '18 at 6:47

Daniel W.

226111

answered Nov 15 '18 at 6:47

Daniel W.

226111

answered Nov 15 '18 at 6:47

Daniel W.

226111

answered Nov 15 '18 at 6:47

Daniel W.

226111

2

Thanks for the suggestion, But this is not going to work in case of a scenario like "number1<=number2" it will end up returning "number1 < = number2" which is not correct

– Sumit Deshpande
Nov 15 '18 at 6:52

wont work for <= will result < =

– styx
Nov 15 '18 at 6:53

add a comment |

2

Thanks for the suggestion, But this is not going to work in case of a scenario like "number1<=number2" it will end up returning "number1 < = number2" which is not correct

– Sumit Deshpande
Nov 15 '18 at 6:52

wont work for <= will result < =

– styx
Nov 15 '18 at 6:53

Thanks for the suggestion, But this is not going to work in case of a scenario like "number1<=number2" it will end up returning "number1 < = number2" which is not correct

– Sumit Deshpande
Nov 15 '18 at 6:52

wont work for <= will result < =

– styx
Nov 15 '18 at 6:53

add a comment |

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