Get the length of a String
As of Swift 4+
It's just:
test1.count
for reasons.
(Thanks to Martin R)
As of Swift 2:
With Swift 2, Apple has changed global functions to protocol extensions, extensions that match any type conforming to a protocol. Thus the new syntax is:
test1.characters.count
(Thanks to JohnDifool for the heads up)
As of Swift 1
Use the count characters method:
let unusualMenagerie = "Koala 🐨, Snail 🐌, Penguin 🐧, Dromedary 🐪"
println("unusualMenagerie has \(count(unusualMenagerie)) characters")
// prints "unusualMenagerie has 40 characters"
right from the Apple Swift Guide
(note, for versions of Swift earlier than 1.2, this would be countElements(unusualMenagerie)
instead)
for your variable, it would be
length = count(test1) // was countElements in earlier versions of Swift
Or you can use test1.utf16count
How equ $ - instruction get the length of a string in nasm syntax?
$
represents the next free location or offset that could hold a byte (here, in the data section, at runtime).
Thus the expression $ - myString
produces the difference between that next location and the label. Since that label occurs earlier, this difference is a positive value, and in fact it is the total length of the preceding db
.
The equ
says to define lengthofString
as a compile time constant, which doesn't consuming any runtime storage.
Note that for this to work, this equ
expression containing $
must appear immediately after the string. Otherwise, if there were intervening data declarations, the count would include them as well, which would be bad.
The following would also work, without using $
, but requires two labels, and the second label must appear right after the data whose length you want:
myString db "This is a string for test", 10
endOfmyString
...
lengthofString equ endOfmyString - myString
The extra label does not add to the storage of the program, and again lengthofString
is computed as a compile (assembly) time constant.
Get length of string using Vimscript
There is len
and strlen
. For strings they are same.
:echo len("Hello")
:echo strlen("Hello")
How to get length of string in javascript without using native length method
You can loop over the string, testing to see whether there is a non-undefined
value at each index (as soon as you get an undefined
value you've run past the end of the string):
function strLength(s) { var length = 0; while (s[length] !== undefined) length++; return length;}
console.log(strLength("Hello")); // 5console.log(strLength("")); // 0
How to calculate the length of the string in python
U can get the length of any string with len()
example:
print (len("string"))
result:
6
Here is a simple example:
In your question you stated that the instruction was to:
return the words if the length of the words is more than the integer.
The below code will do that:
my_str = raw_input("Enter a word: ")
n = raw_input("Enter an integer: ")
def filter_long_words(my_str, n):
if len(my_str) > int(n):
return my_str # assigns the results of my_string to some_word
some_word = filter_long_words(my_str, n)
print some_word
In response to your question in the comments:
def filter_long_words():
my_str = raw_input("Enter a word: ")
n = raw_input("Enter an integer: ")
if len(my_str) > int(n):
return my_str # assigns the results of my_string to some_word
some_word = filter_long_words()
print some_word
One last example. Lets say you are entering several words as one big string.
We can use .split()
to get each word and test it separately.
# simulates raw input of 4 words being typed in at once.
list_of_words_as_a_string = "One Two Three Four"
n = raw_input("Enter an integer: ")
def filter_long_words(word, n):
if len(word) > int(n):
print word
return word # this is only useful if you are doing something with the returned word.
for word in list_of_words_as_a_string.split():
filter_long_words(word, n)
Results when using 3 as the integer:
Enter an integer: 3
Three
Four
Isn't string.length actually a method in JavaScript?
(V8 developer here.)
I can see several issues here that can be looked at separately:
1. From a language specification perspective, is something a method or a property?
Intuitively, the distinction is: if you write a function call like obj.method()
, then it's a method; if you write obj.property
(no ()
), then it's a property.
Of course in JavaScript, you could also say that everything is a property, and in case the current value of the property is a function, then that makes it a method. So obj.method
gets you a reference to that function, and obj.method()
gets and immediately calls it:
var obj = {};
obj.foo = function() { console.log("function called"); return 42; }
var x = obj.foo(); // A method!
var func = obj.foo; // A property!
x = func(); // A call!
obj.foo = 42;
obj.foo(); // A TypeError!
2. When it looks like a property access, is it always a direct read/write from/to memory, or might some function get executed under the hood?
The latter. JavaScript itself even provides this capability to objects you can create:
var obj = {};
Object.defineProperty(obj, "property", {
get: function() { console.log("getter was called"); return 42; },
set: function(x) { console.log("setter was called"); }
});
// *Looks* like a pair of property accesses, but will call getter and setter:
obj.property = obj.property + 1;
The key is that users of this obj
don't have to care that getters/setters are involved, to them .property
looks like a property. This is of course very much intentional: implementation details of obj
are abstracted away; you could modify the part of the code that sets up obj
and its .property
from a plain property to a getter/setter pair or vice versa without having to worry about updating other parts of the code that read/write it.
Some built-in objects rely on this trick, the most common example is arrays' .length
: while it's specified to be a property with certain "magic" behavior, the most straightforward way for engines to implement this is to use a getter/setter pair under the hood, where in particular the setter does the work of truncating any extra array elements if you set the length to a smaller value than before.
3. So what does "abc".length
do in V8?
It reads a property directly from memory. All strings in V8 always have a length field internally. As commenters have pointed out, JavaScript strings are immutable, so the internal length field is written only once (when the string is created), and then becomes a read-only property.
Of course this is an internal implementation detail. Hypothetically, an engine could use a "C-style" string format internally, and then it would have to use a strlen()
-like function to determine a string's length when needed. However, on a managed heap, being able to quickly determine each object's size is generally important for performance, so I'd be surprised if an engine actually made this choice. "Pascal-style" strings, where the length is stored explicitly, are more suitable for JavaScript and similar garbage-collected languages.
So, in particular, I'd say it's fair to assume that reading myString.length
in JavaScript is always a very fast operation regardless of the string's length, because it does not iterate the string.
4. What about String.length
?
Well, this doesn't have anything to do with strings or their lengths :-)
String
is a function (e.g. you can call String(123)
to get "123"
), and all functions have a length
property describing their number of formal parameters:
function two_params(a, b) { }
console.log(two_params.length); // 2
As for whether that's a "simple property" or a getter under the hood: there's no reason to assume that it's not a simple property, but there's also no reason to assume that engines can't internally do whatever they want (so long as there's no observable functional difference) if they think it increases performance or saves memory or simplifies things or improves some other metric they care about :-)
(And engines can and do make use of this freedom, for various forms of "lazy"/on-demand computation, caching, optimization -- there are plenty of internal function calls that you probably wouldn't expect, and on the flip side what you "clearly see" as a function call in the JS source might (or might not!) get inlined or otherwise optimized away. The details change over time, and across different engines.)
How to get the length of a string without calculating the formatting of the text
Yes, there is. I made a function some time ago to do just this.
import re
def len_no_ansi(string):
return len(re.sub(
r'[\u001B\u009B][\[\]()#;?]*((([a-zA-Z\d]*(;[-a-zA-Z\d\/#&.:=?%@~_]*)*)?\u0007)|((\d{1,4}(?:;\d{0,4})*)?[\dA-PR-TZcf-ntqry=><~]))', '', string))
Credits: https://github.com/chalk/ansi-regex/blob/0755e661553387cfebcb62378181e9f55b2567ff/index.js
Getting the length of a string in SQL
As documented for char_length
:
Notes
- With arguments of type
CHAR
, this function returns the formal string length (i.e. the declared length of a field or variable). If you want to obtain the “logical” length, not counting the trailing spaces, right-TRIM
the argument before passing it toCHAR[ACTER]_LENGTH
.
The reasons for this is that char
values are padded with spaces to the declared length, so in essence they are of the declared length.
In other words you need to use:
char_length(trim(trailing from imeprodajalca))
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