Relates to the task of finding a subset of data at the beginning of a set of data. Usually refers to strings but could be other types of data. Please accompany with a language specific tag.
Questions tagged [startswith]
412 questions
1800
votes
18 answers
How to check if a string "StartsWith" another string?
How would I write the equivalent of C#'s String.StartsWith in JavaScript?
var haystack = 'hello world';
var needle = 'he';
haystack.startsWith(needle) == true
Note: This is an old question, and as pointed out in the comments ECMAScript 2015 (ES6)…
sol
402
votes
24 answers
How do I check if a C++ std::string starts with a certain string, and convert a substring to an int?
How do I implement the following (Python pseudocode) in C++?
if argv[1].startswith('--foo='):
foo_value = int(argv[1][len('--foo='):])
(For example, if argv[1] is --foo=98, then foo_value is 98.)
Update: I'm hesitant to look into Boost, since…
Daryl Spitzer
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189
votes
4 answers
How do I find if a string starts with another string in Ruby?
What the best way to find if a string starts with another in Ruby (without rails)?
Guillaume Coté
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164
votes
8 answers
Code not running in IE 11, works fine in Chrome
The following code can be run without a problem in Chrome, but throws the following error in Internet Explorer 11.
Object doesn't support property or method 'startsWith'
I am storing the element's ID in a variable. What is the issue?
function…
Bhushan Dhamdhere
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146
votes
2 answers
Go StartsWith(str string)
Is there a StartsWith(str1, str2 string) function that can check if str1 is a prefix of str2 in Go language?
I want a function similar to the Java's startsWith().
Ammar
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113
votes
10 answers
How to check if a string starts with another string in C?
Is there something like startsWith(str_a, str_b) in the standard C library?
It should take pointers to two strings that end with nullbytes, and tell me whether the first one also appears completely at the beginning of the second…
thejh
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92
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6 answers
Does R have function startswith or endswith like python?
> startsWith('abc', 'a')
[1] TRUE
> startsWith('abc', 'c')
[1] FALSE
> endsWith('abc', 'a')
[1] FALSE
> endsWith('abc', 'c')
[1] TRUE
user2165
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89
votes
11 answers
Why does "abcd".StartsWith("") return true?
Title is the entire question. Can someone give me a reason why this happens?
Dested
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64
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7 answers
Case-insensitive string startswith in Python
Here is how I check whether mystring begins with some string:
>>> mystring.lower().startswith("he")
True
The problem is that mystring is very long (thousands of characters), so the lower() operation takes a lot of time.
QUESTION: Is there a more…
Nicolas Raoul
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60
votes
6 answers
Regex to check with starts with http://, https:// or ftp://
I am framing a regex to check if a word starts with http:// or https:// or ftp://, my code is as follows,
public static void main(String[] args) {
try{
String test = "http://yahoo.com";
…
Abhishek
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59
votes
1 answer
If strings starts with in PowerShell
Is there a way to check if a string starts with a string?
We are checking the groupmembership from the AD user. Our AD groups look like this: S_G_share1_W
The script for connecting the networkshares should only run if the groupname starts with…
JocSch
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58
votes
2 answers
Why is string's startswith slower than in?
Surprisingly, I find startswith is slower than in:
In [10]: s="ABCD"*10
In [11]: %timeit s.startswith("XYZ")
1000000 loops, best of 3: 307 ns per loop
In [12]: %timeit "XYZ" in s
10000000 loops, best of 3: 81.7 ns per loop
As we all know, the in…
WKPlus
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55
votes
3 answers
How do I ignore case when using startsWith and endsWith in Java?
Here's my code:
public static void rightSel(Scanner scanner,char t)
{
/*if (!stopping)*/System.out.print(": ");
if (scanner.hasNextLine())
{
String orInput = scanner.nextLine;
if (orInput.equalsIgnoreCase("help")
{
…
Matao Gearsky
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55
votes
5 answers
Why is startswith slower than slicing
Why is the implementation of startwith slower than slicing?
In [1]: x = 'foobar'
In [2]: y = 'foo'
In [3]: %timeit x.startswith(y)
1000000 loops, best of 3: 321 ns per loop
In [4]: %timeit x[:3] == y
10000000 loops, best of 3: 164 ns per…
Andy Hayden
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40
votes
4 answers
What is the easiest way to get all strings that do not start with a character?
I am trying to parse about 20 million lines from a text file and am looking for a way to do some further manipulations on lines that do not start with question marks. I would like a solution that does not use regex matching. What I would like to do…
drbunsen
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