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.

learn more… | top users | synonyms

0
votes
1answer
109 views

exception for string literal conventions

If I'm used to use ' for string literals in PHP, would it be better if I'll stick to it in any situation or can there be exceptions when it would increase readability? example: $foo = "bar'baz"; // ...
1
vote
2answers
4k views

Why doesn't Ruby have implicit conversion of Fixnum into String?

Ruby normally makes things easy. However, it doesn't allow implicitely converting a number to a string: 2.0.0p247 :010 > "a"+1 TypeError: no implicit conversion of Fixnum into String Why is this ...
1
vote
1answer
271 views

Algorithm to create permutations for a given alphabet based on a sequence number

I would like to have a function that will create a word (always the same word) for a given sequence number based on a given alphabet. word(0, [a,b,c]) = a word(1, [a,b,c]) = b word(2, [a,b,c]) = c ...
-1
votes
2answers
814 views

Word recognition in a string without spaces or punctuation marks

I have a small C# project that reads a file and gives me an output: a string that does not contain spaces nor any types of punctuation marks. It may also contain a few misspellings. Ex. Output: ...
1
vote
2answers
298 views

What's the difference of an object being final and an object being immutable in java?

final String str = "do not change me"; str = "why not?"; //it will result in compile time error saying that final fields can not be re-assigned once created i.e. the reference cannot be changed ...
0
votes
3answers
193 views

How can I handle this string concatenation in C in a reusable way

I've been writing a small C application that operates on files, and I've found that I have been copy+pasting this code around my functions: char fullpath[PATH_MAX]; fullpath[0] = '\0'; ...
0
votes
1answer
295 views

What is the purpose of chunking strings in natural language processing?

I see many examples of libraries that use a 'chunker' and also people asking how to write chunkers, but what is this for and why do we need it? Isn't it enough to split a text by whitespace or other ...
6
votes
5answers
1k views

Why doesn't Haskell have a 'format' function for string interpolation?

I'm trying to use Shake and I stumbled upon the following problem: there's no easy and convenient way to interpolate a string. I know about Text.Printf — it's not what I'm looking for. The ...
1
vote
4answers
484 views

How can I take a list of tokens (of variable number) and know what each token means?

I have to read a text document with data formatted as follows: (a couple of examples) 07 M W F 1400 1450 C 2004 M W F 0900 1030 EN 2036 06 M T R 1300 1350 EN 1003 17 T R 0900 1015 EN 1052 The ...
1
vote
1answer
161 views

Search Substring in String collection

I have a big collection of strings a[1], …, a[N] where N is about several millions. I am provided a string m and I need to iterate over all the strings a[i] that contain m. In other words, I need to ...
14
votes
3answers
3k views

How many strings are created in memory when concatenating strings in Java?

I was asked about immutable strings in Java. I was tasked with writing a function that concatenated a number of "a"s to a string. What I wrote: public String foo(int n) { String s = ""; for ...
2
votes
1answer
138 views

Comparing strings against a pool of words

I am creating an app where the user enters 8 characters. After he enters the string I have to see if it is an eight letter word. If not, check if contains a seven letter word etc. I am checking ...
2
votes
6answers
1k views

Settle an Argument: String vs. Array?

True or False: A string is the same thing as an array. I had an interview the other day and the above question was asked. I said false, but the interviewer said it was actually true. I explained to ...
-1
votes
5answers
957 views

How common is string manipulation, really? [closed]

I've noticed a lot of programming introductions (almost any language) usually include a heavy barrage of string manipulation quite early, such as: Count the number of "xx" in the given string. We'll ...
-1
votes
1answer
88 views

Code execution within delimiters [closed]

Is there any way I can execute a block of code in a loop, like so: [ some code goes here ] Where the delimiters are "[" and "]", and also allowing for nested blocks, i.e.: [the user can create ...
8
votes
1answer
467 views

Match two strings but allow for a degree of error

How can I match two strings, but at the same time allow for X number of characters to be incorrect in the match. The number of errors should be a controllable variable. While X number of characters ...
2
votes
5answers
664 views

Find pattern in a string

How would one approach the following question: We have two strings: a normal alphanumeric string and a pattern string. the pattern string can be composed by alphanumeric chars plus the char "?" ...
1
vote
1answer
473 views

PHP Simplest XML tokenizer for string processing?

I need to do some text processing tasks with short XML fragments. The section "details" shows an example... My solution is to use a tokenizer based on regular expresions, but it is not elegant and not ...
0
votes
6answers
4k views

Converting an empty string to a number [closed]

If you are designing a function which should conver a string to an integer, how would you convert an empty string? The question is only about this one particular input value (empty string). Between ...
1
vote
4answers
2k views

What does it mean to perform an operation “In Place” for Interpreted Languages?

Programming question: Reverse words in a string (words are separated by one or more spaces). Now do it in-place. What does "in-place" mean in the above context for an interpreted language ...
59
votes
11answers
22k views

Why is String immutable in Java?

I couldn't understand the reason of it. I always use String class like other developers, but when I modify the value of it, new instance of String created. What might be the reason of immutability ...
8
votes
1answer
1k views

Possible Damerau-Levenshtein improvement?

I recently implemented the Damerau-Levenshtein distance algorithm from the pseudocode on Wikipedia. I couldn't find any explanation of exactly how it works and the pseudocode uses completely ...
0
votes
3answers
102 views

How to manage intermediate outputs efficiently?

I am implementing a C preprocessor in C... I have the three functions: trigraph replacing function Line splicing function comment removing function However these functions work separately on ...
3
votes
5answers
3k views

A string is immutable, so why are they not all constants?

The string type is immutable. We can use the const keyword with strings in high level language like .NET. My understanding of 'const' means constant (it remains the same, we can't change the value). ...
7
votes
3answers
623 views

Longest subsequence without string

Does there exist a dynamic programming algorithm to find the longest subsequence in a string X that does not contain Y as substring? Just that this problem seems so similar to other DP string ...
6
votes
2answers
248 views

Index independent character comparison within text blocks

I have the following task: developing a program where there is a block of sample text which should be typed by user. Any typos the user does during the test are registered. Basically, I can compare ...
3
votes
3answers
3k views

Try to find a word in the dictionary that has most letters given

I recently came across an algorithm design problem that I'd like some help with: Given some letters, for example a,e,o,g,z,k,l,j,w,n and a dictionary of words. Find a word in the dictionary that ...
0
votes
1answer
274 views

Algorithm Identification [ String & Dictionary ]

I recently heard of an interview question: Given a string and a dictionary. Break the string into meaningful words and I remember solving this before with dynamic programming fairly quickly (maybe ...
3
votes
5answers
8k views

How do you compress ASCII strings into smaller bytes?

I'm working with an embedded device with a unique protocol that sends messages to other devices and I'm making an application that parses the sent packets. Each packet carries 8 bytes. The protocol is ...
26
votes
6answers
119k views

Is initializing a char[] with a string literal bad practice?

I was reading a thread titled "strlen vs sizeof" on CodeGuru, and one of the replies states that "it's anyways [sic] bad practice to initialie [sic] a char array with a string literal." Is this ...
12
votes
3answers
13k views

Which string search algorithm is actually the fastest?

I have been stuck for some time on which is the fastest string search algorithm, heard many opinions, but in the end I'm not sure. I have heard some people saying that the fastest algorithm is ...
6
votes
1answer
671 views

Finding occurrences of a useful words and phrases in strings

I am building an app that analyzes posts by people by pulling their Tweets and Facebook posts. I need to process all the posts and find useful phrases. What I mean by useful is that, any word or ...
3
votes
3answers
278 views

Storing lots of large strings with frequent “appends” and few reads

In my current project, I need to store a very long ASCII string to each instance of a given object. This string will receive an 2 appends per minute and will not be retrieved so frequently. The ...
1
vote
2answers
552 views

Looking for a non-cryptographic hash function that returns a single character

Suppose I have a dictionary of ASCII words stored in uppercase. I also want to save those words into separate files so that the total word count of each file is approximately the same. By simply ...
19
votes
2answers
8k views

Why does Java use UTF-16 for internal string representation?

I would imagine the reason was fast, array like access to the character at index, but some characters won't fit into 16 bits, so it wouldn't work... So if you have to handle special cases anyways, ...
1
vote
1answer
179 views

How to implement string matching based on a pattern

I was asked to build a tool that can identify if a string match a pattern. Example: {1:20} stuff t(x) {a,b,c} would match: 1 stuff tx a 20 stuff t c It is a sort of regex but with a ...
6
votes
2answers
2k views

Complex string matching with fuzzywuzzy

I'm attempting to write a process that matches obscure strings to a single 'master string' for further processing. I have a lot of data that looks something like this: Basketball Basket Ball Football ...
9
votes
1answer
5k views

Shortest Common Superstring: find shortest string that contains all given string fragments

Given some string fragments, I would like to find the shortest possible single string ("output string") that contains all the fragments. Fragments can overlap each other in the output string. ...
0
votes
1answer
1k views

Removing occurrences of characters in a string

I am reading this book, Programming Interviews Exposed by John Mongan et. al and in chapter 6 they are discussing removing all instances of characters in a src string using a removal string, e.g. ...
9
votes
2answers
21k views

When should I use StringBuilder or StringBuffer?

In a production web application, my fellow programmers used StringBuffer everywhere. Now I am taking care of application development and corrections. After reading StringBuilder and StringBuffer I ...
2
votes
2answers
133 views

What direction should I consider the offset when searching strings in reverse?

I'm making an indexOfReverse utility function in my C++ program, and I have caught a bit of a snag. Implementing the offset and maxOffset in my indexOf was very intuitive to me.. These start from the ...
2
votes
3answers
400 views

Why are the arguments for substring functions mismatched?

In many languages, the substring function works like this: substring(startIndex, endIndex) returns the substring from startIndex until endIndex-1 (if you view startIndex and endIndex as 0-based) / ...
7
votes
5answers
875 views

Should functions of a C library always expect a string's length?

I'm currently working on a library written in C. Many functions of this library expect a string as char* or const char* in their arguments. I started out with those functions always expecting the ...
9
votes
1answer
2k views

How does PHP internally represent strings?

UTF8? UTF16? Do strings in PHP also keep track of the encoding used? Let's look at this script for example. Say I run: $original = "शक्नोम्यत्तुम्"; What actually happens? Obviously I think ...
19
votes
1answer
9k views

C++11 includes std::stoi, why not std::itos?

I noticed to my glee that C++11 has a std::sto@ family of functions for easily unpacking ints/floats/longs whatever from strings. I'm surprised however, that the opposite isn't implemented. Why didn't ...
11
votes
6answers
2k views

Is it inefficient to concatenate strings one at a time?

I recall back from my days of programming in C that when two strings are joined, the OS must allocate memory for the joined string, then the program can copy all the string text over to the new area ...
15
votes
5answers
10k views

Should a string constant be defined if it's only going to be used once?

We're implementing an adapter for Jaxen (an XPath library for Java) that allows us to use XPath to access the data model of our application. This is done by implementing classes which map strings ...
1
vote
4answers
155 views

Possible applications of algorithm devised for differentiating between structured vs random text

I have written a program that can rapidly (within 5 sec on a 2GB RAM desktop, 2.33 Ghz CPU) differentiate between structured text (e.g English text) and random alphanumeric strings. It can also ...
9
votes
2answers
1k views

Why are Python strings allocated on the stack?

According to this Python code visualizer, Python strings are allocated on the stack and not on the heap. Why is this? I thought they would be similar to Java where Strings are allocated on the heap.
13
votes
5answers
10k views

How can I extract words from a sentence and determine what part of speech each is? [closed]

I want to write something that takes a sentence and identifies each word it contains and defines what part of speech each word is. For example Hello World, I am a sentence would return this ...