What are the string types and common methods in Swift

This article mainly introduces the string types and commonly used methods in Swift, which have a certain reference value, interested friends can refer to, I hope you can learn a lot after reading this article, the following let the editor take you to understand it.

1. Construct / / directly assign text = "" / / 1. Construction method text = String () / / "" / / string construction text = String ("William") / / "William" / / integer construction text = String / / "888" / / floating point construction text = String / / "8.88" / / character construction text = String ("a") / / "a" / / Boolean construction text = String (true) / / "true" / / tuple construction text = String (describing: (5) ) / / "(5,5.0, true)" / / list construction text = String (describing: [1,2,3,4]) / / "[1,2,3,4]" / / format string text = String (format: "Hello,% @", "William") / / "Hello, William" 2. Splice var text1 = "hello," var text2 = "William" var result = text1 + text2print (result) / / hello, William// 3. Insert a simple value in a string using\ (), similar to ${} var target = "Hello,\ (66)" / / Hello in Kotlin, 66var target2 = "Hello,\ (text2)" / / Hello, Williamvar target3 = "Hello,\ (1 + 2)" / / hellow, 33. Character var char: Character = "e" / / "e" var char2 = Character ("e") / / "e" / / occupies 16 bytes var size = MemoryLayout.size / / 16 hand / character array var array: [Character] = ["W", "I", "l", "l", "I", "a" "m"] / / construct Stringvar newStr = String (array) / / William// traversal string let city = "Shanghai" for cha in city {print (cha)} 4. Escape character

Escape characters are often used in typesetting

/ /\ 0: for blank / /\\: for backslash / /\ t: for tab / /\ n: for line feed / /\ r: for carriage return / /\': for single quotation marks / /\ u {}: create characters var code = "\ u {0068}\ u {0065}\ u {006c}\ u {006c}\ u {006f } "/ / hellovar escapeChar =" blanks:\ 0 backslash:\\ tab:\ t newline\ ncarriage return:\ r single quotation marks:\ 'double quotes:\ "print (escapeChar) 5. Common methods / / string null var emptyStr = "" if emptyStr.isEmpty {print ("string is empty")} if emptyStr.count = = 0 {print ("string count is 0")} / / string size is compared one by one, let str1 = "100a", str2 = "101a" if (str1 < str2) {print ("str1 < str2")} / / string equal, all characters are compared to be equal Is the equivalent string if (str1 = = str2) {print ("str1 < str2")} / / using the subscript access character var indexStr = "Hello" William "/ / get the starting subscript var startIndex: String.Index = indexStr.startIndexvar endIndex: String.Index = indexStr.endIndex// get the character var afterChar = indexStr [indexStr.index (after: startIndex)] / / edeband / get the character var beforeChar = indexStr [indexStr.index (before: endIndex)] / / var beforeChar / corresponding to the subscript before a subscript. Operator to specify a range, move 4 bits backward from startIndex to intercept substring var subStr = indexStr [startIndex...indexStr.index (startIndex, offsetBy: 4)] / / hello// move forward from endIndex 7 bit truncated substring var subStr2 = indexStr [indexStr.index (endIndex, offsetBy:-7)..