Questions tagged [strings]

A "string" is a sequence of characters typically representing a unit of human-readable text. Questions on this topic deal with processing strings in programs, and how various languages and environments define and manipulate strings.

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Strip spaces before saving to DB or while outputting?

Imagine scenario: need to strip out spaces from a string to be used lets say in url. Now would it be smart to do this once before saving in DB, and than use raw db results when outputting. Or would ...
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-2 votes
1 answer
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What string will match the regular expression (^$)|(^.*\\{count\\}.*$)\n?

I'm trying to pass a parameter to create a thumbnail in AWS Elastic transcoder, which shouldn't be that difficult except I know nothing about regular expressions. My log is giving me the following ...
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10 votes
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What's the complexity of Java's string split function?

My string is of type"abacsdsdvvsg" or"a a a a a a a" And I use String[] stringArray = s.split(""); or String[] stringArray = s.split(" "); I'm wondering what would be the complexity(in O(string length)...
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Why are the punctuation characters in the ASCII table all over the place?

In the ASCII table, punctuation characters appear between the non-printing characters and before the numbers (!"#$%&')*+,-./), between the numbers and the uppercase letters (:;<=>?@), ...
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4 answers
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How can I count frequency of strings?

I have 3 billion strings. I want to make a frequency map so I can discard strings that occur fewer than 100 times or more than 100,000 times. What kind of data structure(s) should I use? I'm ...
1 vote
4 answers
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immutable string in array, reference type vs value type

Trying to understand strings better in C# Are these assertions correct? string is immutable string is reference type but behaves like value type For these code samples... string x = "one" (...
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2 answers
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Variable can't hold str() method information with "pure" word in brackets... why?

I've recently bumped into string methods and mainly str() method caught my interest because, it makes string out of every type of data? integers, booleans and so on. And if you want, they can be ...
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1 answer
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Problem while printing characters Difference between System.out.println('A') and System.out.println(+'A') [closed]

Why is it that : System.out.println(+'A') //gives output as 65 System.out.println('A') //gives output as A Also System.out.println(8+4+'A'+"PRIME"+4+4+'A'); gives output as 77PRIME44A ...
7 votes
7 answers
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How to create multiline strings for sql queries that are readable, maintainable and fast?

I have some SQL commands that I am trying to figure out the best way to have them in code so that: 1. They are very readable 2. They would be easy to update 3. They won't be performance overhead due ...
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1 vote
2 answers
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How can I include common strings (regexes) in several projects written in different languages?

I have a simple Go library (~300 lines, mostly type declarations and nice methods and compatibility methods for gomobile etc., also pretty-printing scripts). The heart of the whole project are two ...
12 votes
2 answers
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Memory usage of JavaScript string type with identical values

JavaScript string type is immutable, but does it mean identical strings will share memory? Say two strings are created in complete different places, will a modern JavaScript engine be smart enough to ...
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8 votes
3 answers
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Compiling for string and wstring

I'm creating a library. I want to use it in multiple projects which may use multi-byte or unicode (std::string or std::wstring). I've adopted the old MS method of conditional compiling: namespace ...
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1 answer
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URL endpoint concatenating

When writing API clients, what is considered the proper way of concatenating a URL together with multiple endpoints? For example with the Blizzard API: WowEndpoints := [...]string{"achievements", "...
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7 votes
2 answers
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Finding and counting equal substrings in a set of strings

I'm thinking about a way of finding similar parts in Strings. I have a set of strings of varying length i.e: The quick brown fox jumps fox force five the bunny is much quicker than the fox is First, ...
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2 answers
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Do any languages other than Haskell implement strings as linked lists of characters?

Haskell’s String type is an alias for [Char] (i.e. a linked list of Chars). Does any other language use an implementation of strings like this?
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5 votes
2 answers
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finding optimal token definitions for compression

I have a collection of strings which have a lot of common substrings, and I'm trying to find a good way to define tokens to compress them. For instance, if my strings are: s1 = "String" s2 = "Bool" ...
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1 answer
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Most Pythonic way to remove first match of potential leading strings?

This is a bit difficult to describe, but I'll do my best. In Python, I can use string.startswith(tuple) to test for multiple matches. But startswith only returns a boolean answer, whether or not it ...
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1 answer
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Parsing a string with multiple levels of key value pairs

I need to write a part of the program which will work with a string, find in it some substrings and copy they to dictionary. Example of the string: thestring ='\ #: somethings\nchars0 "substr0"\...
3 votes
2 answers
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Most efficient strategy for search large text areas for multiple values

I have a requirement for a service that does the following. Take a block of text and identify the server names in it (by name or ip address). So given: Lorem ipsum dolor sit amet, consectetur ...
6 votes
4 answers
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Is "use "abc".equals(myString) instead of myString.equals("abc") to avoid null pointer exception" already problematic in terms of business logic?

I heard numerous times that when comparing Strings in Java, to avoid null pointer exception, we should use "abc".equals(myString) instead of myString.equals("abc"), but my question is, is this idea ...
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3 votes
2 answers
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Should arbitrary numbers be stored as strings in a database?

I'm using Google as a login system for my latest project. So, my users table has a column named googleid, which stores Google's unique user id, which is a number, with a few dozen digits. For example, ...
-1 votes
1 answer
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Find missing number in sequence in string [closed]

I have a string that contains numbers in sequence. There are no delimiters between numbers. I have to find missing number in that sequence. For example: 176517661768 is missing the number: 1767 ...
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7 votes
2 answers
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Compile-time checking for NULL initialized std::string

This is sort of the complementary question to How to best protect from 0 passed to std::string parameters?. Basically, I'm trying to figure out whether there is a way to have the compiler warn me if a ...
5 votes
4 answers
3k views

Why do so many languages restrict string literals to a single source line? [closed]

In, for example, the Bash scripting language, the following creates a string called $VAR which begins at the first " quote and continues until the next unescaped " quote. $VAR=" hello world! ...
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Algorithm to get all possible forms of a word with varying suffixes [closed]

I'm writing an application in javascript where given a word, I need to get all the possible versions of the word with the suffix being the difference between each form. For example: "sponsor" should ...
-1 votes
1 answer
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In which cases and examples String in Java is not immutable? [duplicate]

If Strings are immutable in Java, why is the output of this code 2GB, instead of 1GB? class Laptop { String memory = "1GB"; } class Workshop { public static void main(String args[]) { ...
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Speeding up appending text in C# [duplicate]

I'm trying to append text to a large amount of strings (in the thousands), and also do some other string manipulations. However, I have about 60 lines of if/else and string appending and it takes ...
-1 votes
2 answers
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How to scramble a word, keeping first and last characters the same?

I have a task, which is to scramble a single word, whose size is greater than 3 letters. The scrambled word must not be equal to the original, and the first and last letters of the word must remain ...
7 votes
6 answers
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Is "string literal" always the same as "hard-coded string"? [closed]

I am learning programming and often see the term "string literal" being used in various places. From the looks of it, it seems to be a synonym for "hard-coded string", but on another hand the term ...
96 votes
5 answers
229k views

Why is %s better than + for concatenation?

I understand that we should use %s to concatenate a string rather than + in Python. I could do any of: hello = "hello" world = "world" print hello + " " + world print "%s %s" % (hello, world) print ...
3 votes
2 answers
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Burrows-Wheeler transform backward search: how to find suffix index?

BWT backward search algorithm is pretty straightforward if we only need the multiplicity of a pattern. However I also need to find the suffix indices (i.e. positions in the reference string where a ...
2 votes
3 answers
496 views

Why do most language's definition of substring allow substring("abc", 3) => ""

I've seen most languages have it be the case for their substring method that using the length of a given string in the method as the start index will give you an empty string. It is most definitely ...
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Find index of string in an array of strings where overlap could occur

I am having some trouble writing a variant of sub-string search. Essentially the goal is to write a method that can perform sub-string search except that the source data is in an array of Strings ...
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1 vote
2 answers
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Incrementing Strings in PHP (and Perl)

PHP allows you to increment strings. Why? Let's jump ahead a bit. Take the following code: $string = '9ZzZ'; echo ++$string; // 10AaA From a purist point of view this may seem like nonsense, ...
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1 vote
0 answers
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Algorithm for evaluating line breaks efficiently [closed]

Consider following problem : Given: String input with the length n Font(-metrics) - potentially slow in usage Bounds of an abstract Textview which shall contain the text in a specific manner: e.g ...
11 votes
4 answers
17k views

In C# Is using private constant strings better than using strings directly in the code? [closed]

Consider the following two cases: case 1: class A { private const string MyConst="Hello"; internal void CallMe() { System.Console.WriteLine(MyConst); } } Case2: class A { ...
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1 answer
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What operating systems will "\n" create a new line in? (Java) [closed]

(Java Version 8 Update 60) Hello. I am currently writing a program for my first Java assignment in college. My question is, in what operating systems will System.out.println("Hello,\n World"); ...
3 votes
1 answer
174 views

CharSequence to represent a named object

I always followed the opinion to not abuse interfaces in case of decomposition. Usually I only implement them if I am absolutely sure to have a "is-a"-relation and avoid implementing them if there is ...
34 votes
2 answers
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Why are C string literals read-only?

What advantage(s) of string literals being read-only justify(-ies/-ied) the: Yet another way to shoot yourself in the foot char *foo = "bar"; foo[0] = 'd'; /* SEGFAULT */ Inability to elegantly ...
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1 vote
2 answers
547 views

Why are Strings in StringPool considered insecure?

Passwords are recommended to be stored in char[] instead of String, as Strings are stored in StringPool. Read more here As per this question Strings in StringPool are not available directly. To ...
4 votes
2 answers
706 views

Are string characters assigned a numerical value in context of how they are assigned in a programming language?

For context I am fairly new to programming after returning back to it after programming a number of years ago... I was reading Bjarne's intro programming with C++ and was wondering if alphabetical ...
4 votes
2 answers
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why regex, when using global search and {0,} quantifier, match the end of the string?

I have asked a question here about js, regex, quantifiers and global search. I've understood finally how this works, but, let's take a concrete example and then I`ll write my question. Based on the ...
1 vote
0 answers
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clustering of strings with variable-length prefixes

I've got bunch of strings with variable-length prefixes (or postfixes - I can always revert them) as follows: 0155555555 523455555555 755555555 ... 87129999999999999 119999999999999 09119999999999999 ...
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Why can't I use an operator like plus sign to concatenate strings? [closed]

Why in Objective-C we should be typing explicit references to methods like stringByAppendingString to concatenate strings, when in some other languages we can use operators for that? For example, ...
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1 vote
3 answers
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Why should I use lookup tables at all?

This question confirmed, what I was already aware of -- instead of directly storing strings in table, I should rather use integers or enums and join them with lookup table, to get, as a result, string,...
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2 votes
3 answers
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At which point using string-based enums can become a real problem?

This is a direct follower to this question. An answer given to that questions says (my understanding), that nowadays using string-based enums instead of integers isn't a much problem, because hosting ...
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1 vote
4 answers
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How can I avoid the use of strings?

I'm implementing a program where the user can 'create a musical scale' from a variety of notes (identified by their names), and the program will generate music from this scale. I want to implement a ...
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3 votes
0 answers
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String Rearrangement Algorithm in Visual Basic

Beginning programmer here (mostly engineer). I'm making trapezoids in layers. We begin with the small length layer, and end with the longest length layer. I want my user to input in a desired ...
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6 votes
1 answer
477 views

Use StringLike instead of String in Scala?

Scala has the StringLike trait. Let's say I want to create a case class Name and internally it should save the name with some characters. Should I use case class Name(name: StringLike) or case class ...
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40 votes
6 answers
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Hardcoding strings that will never change

So, in my efforts to write a program to conjugate verbs (algorithmically, not through a dataset) for French, I've come across a slight problem. The algorithm to conjugate the verbs is actually fairly ...