“This is the fifth day of my participation in the Gwen Challenge in November. Check out the details: 2021 Last Gwen Challenge”

preface

As the most common type used in development, string follows certain specifications, which can effectively improve the readability of code. The following recommended practices for using strings in Dart.

String conjunction

If you have two literal strings (not variables, but strings in quotes), you don’t need to use + to concatenate them. Just put them next to each other, which is good for creating long strings that can’t fit on a single line.

///recommended
String f = 'aaa''bbb' // Applies only to constants but not to variables
///The + sign is not recommended
String f = 'aaa' + 'bbb'
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String definition

Use three single quotes or three double quotes to create a multi-line string with built-in formatting such as newline and indentation

String f = ''' my name is rex nice to meet you! ' ' '
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Common definition, using single or double quotation marks

String a = 'aaa';
String b = "bbb";
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Special characters such as the raw string escape character created with r are printed instead of being automatically escaped

String f = r'Hello \n World';
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Use interpolation to combine strings and values

Avoid using + to associate literal strings with variable values. Build the connection using the $,${} identifier.

void setName(Person person){
    String f = 'my name ${person.name}'
}

void setName(String name){
    String e = 'my name is $name'
}
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Change case

Business comparisons often ignore case and only compare content

String f = "aaaBBBccc";
// Uppercase to lowercase
f.toLowerCase();
// Change lowercase to uppercase
f.toUpperCase();
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Remove the blank space

Removing whitespace is also a common use in development

String f = " aaabbb "
// Remove the left and right Spaces
f.trim();
// remove the left space
f.trimLeft();
// remove the space on the right
f.trimRight();
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Complete the length, and replace the remaining bits with the specified string

String f = "111";
// The left side defaults to "complete"
f.padLeft(6); / / "111"
// Use "c" to complete the left 3 bits
f.padRight(6."c"); //"111ccc"
// The remaining 3 bits each specify that the total length is not 6 when replaced with "dd"
f.padRight(6."cc"); //"111cccccc"
If the specified length is less than the length of the original string, the original string is returned
f.padLeft(2); / / "111"
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