UPDATE: I liked this question so much, I just blogged it. See Strings, immutability and persistence The short answer is: O(n) is O(1) if n does not grow large. Most people extract tiny substrings from tiny strings, so how the complexity grows asymptotically is completely irrelevant. The long answer is: An immutable data structure built … Read more
All of the following examples use var str = “Hello, playground” Swift 4 Strings got a pretty big overhaul in Swift 4. When you get some substring from a String now, you get a Substring type back rather than a String. Why is this? Strings are value types in Swift. That means if you use … Read more
Using regular expressions – documentation for further reference import re text=”gfgfdAAA1234ZZZuijjk” m = re.search(‘AAA(.+?)ZZZ’, text) if m: found = m.group(1) # found: 1234 or: import re text=”gfgfdAAA1234ZZZuijjk” try: found = re.search(‘AAA(.+?)ZZZ’, text).group(1) except AttributeError: # AAA, ZZZ not found in the original string found = ” # apply your error handling # found: 1234
str1.toUpperCase().contains(str2.toUpperCase()) UPD: Original answer was using toLowerCase() method. But as some people correctly noticed, there are some exceptions in Unicode and it’s better to use toUpperCase(). Because: There are languages knowing more than one lower case variant for one upper case variant.
You can do exactly the same call with Swift: Swift 4 & Swift 5 In Swift 4 String is a collection of Character values, it wasn’t like this in Swift 2 and 3, so you can use this more concise code1: let string = “hello Swift” if string.contains(“Swift”) { print(“exists”) } Swift 3.0+ var string … Read more
Use std::string::find as follows: if (s1.find(s2) != std::string::npos) { std::cout << “found!” << ‘\n’; } Note: “found!” will be printed if s2 is a substring of s1, both s1 and s2 are of type std::string.
You can use Parameter Expansion to do this. If a is constant, the following parameter expansion performs substring extraction: b=${a:12:5} where 12 is the offset (zero-based) and 5 is the length If the underscores around the digits are the only ones in the input, you can strip off the prefix and suffix (respectively) in two … Read more
The difference is in the second argument. The second argument to substring is the index to stop at (but not include), but the second argument to substr is the maximum length to return. Links? https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Global_Objects/String/substr https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Global_Objects/String/substring
slice() works like substring() with a few different behaviors. Syntax: string.slice(start, stop); Syntax: string.substring(start, stop); What they have in common: If start equals stop: returns an empty string If stop is omitted: extracts characters to the end of the string If either argument is greater than the string’s length, the string’s length will be used … Read more
Like this: if (str.indexOf(“Yes”) >= 0) …or you can use the tilde operator: if (~str.indexOf(“Yes”)) This works because indexOf() returns -1 if the string wasn’t found at all. Note that this is case-sensitive. If you want a case-insensitive search, you can write if (str.toLowerCase().indexOf(“yes”) >= 0) Or: if (/yes/i.test(str)) The latter is a regular expression … Read more