473,832 Members | 2,118 Online
Bytes | Software Development & Data Engineering Community
+ Post

Home Posts Topics Members FAQ

How to find the length of an iterator?

What is the best way to find out the length of an iterator? len()
doesn't work. In the above code snippet[1] I am only interested in the
index (= length of the iterator), so I'm using len(list(iterat or))...

Anything better?

Thanks, Thorsten

[2]
def part(seq, func):
from itertools import takewhile
index = len(list(takewh ile(func, seq)))
return [seq[:index], seq[index:]]
Jul 18 '05 #1
2 5993
Thorsten Kampe wrote:
What is the best way to find out the length of an iterator? len()
doesn't work. In the above code snippet[1] I am only interested in the
index (= length of the iterator), so I'm using len(list(iterat or))...

Anything better?


Its the nature of an iterator that it doesn't support anything beyond access
to the current item and signaling when its finished. So if you need the
length, try to get a hold on the underlying connection.

--
Regards,

Diez B. Roggisch
Jul 18 '05 #2
Diez B. Roggisch wrote:
Its the nature of an iterator that it doesn't support anything beyond
access to the current item and signaling when its finished. So if you need
the length, try to get a hold on the underlying connection.


s/connection/collection/

Got confused on my new touchstream dvorak keyboard :)
--
Regards,

Diez B. Roggisch
Jul 18 '05 #3

This thread has been closed and replies have been disabled. Please start a new discussion.

Similar topics

7
12827
by: zhou | last post by:
Hi there, We have a compiler specific issue which requires us to force template instantiation. This works fine. The problem comes when I try using std:find() on vector. Since vector has no member function find() and I have to use std::find(). The linker fails on unsatisified symbols in find(). I think this is because find() is a template function and I have to force instantiation. However, I donot know the correct syntax of doing so....
3
4446
by: Prakash Bande | last post by:
Hi, I have bool operator == (xx* obj, const string st). I have declared it as friend of class xx. I am now able to do this: xx ox; string st; if (&ox == st) { } But, when I have a vector<xx*> and use stl find string xyz;
4
1467
by: Vince | last post by:
Hi, I am not used to template and I cannot find what's wrong with this code : Compiler(MSVS 7) complains at line : class iterator : public std::iterator<... Here is the source code
5
13863
by: ief | last post by:
hi all, i'm trying to check the length of a numeric value in a string. this is what i need to do: I have a string "Mystring (253)" and a string "SecondString (31548745754)" Now i have to check if the string contains more than 3 numeric characters because i must only process the ones with more than 3.
14
22586
by: micklee74 | last post by:
hi say i have string like this astring = 'abcd efgd 1234 fsdf gfds abcde 1234' if i want to find which postion is 1234, how can i achieve this...? i want to use index() but it only give me the first occurence. I want to know the positions of both "1234" thanks
5
2581
by: Draw | last post by:
Hi All, Just a thought, about the find() algorithm in the C++ STL. I read that the find algorithm can take a range of iterators. If it does not find the element it is looking for in that range it returns the iterator to the last element in the range, not to the last element in the container, to the last element in the range. That being said, how can we tell if find() has been successful in finding the element we need? Its easy when we...
16
2594
by: mailforpr | last post by:
How do I do that? The thing is, the only information I have about the iterator is the iterator itself. No container it is belonging to or anything. Like template<Iteratorvoid totally_isolated(Iterator& it) { //how do I find out if it points to the end node? }
8
12271
by: bearophileHUGS | last post by:
Often I need to tell the len of an iterator, this is a stupid example: len isn't able to tell it: Traceback (most recent call last): File "<stdin>", line 1, in <module> TypeError: object of type 'generator' has no len() This is a bad solution, it may need too much memory, etc:
16
8959
by: vizzz | last post by:
Hi there, i need to find an hex pattern like 0x650A1010 in a binary file. i can make a small algorithm that fetch all the file for the match, but this file is huge, and i'm scared about performances. Is there any stl method for a fast search? Andrea
0
10781
Oralloy
by: Oralloy | last post by:
Hello folks, I am unable to find appropriate documentation on the type promotion of bit-fields when using the generalised comparison operator "<=>". The problem is that using the GNU compilers, it seems that the internal comparison operator "<=>" tries to promote arguments from unsigned to signed. This is as boiled down as I can make it. Here is my compilation command: g++-12 -std=c++20 -Wnarrowing bit_field.cpp Here is the code in...
0
10499
jinu1996
by: jinu1996 | last post by:
In today's digital age, having a compelling online presence is paramount for businesses aiming to thrive in a competitive landscape. At the heart of this digital strategy lies an intricately woven tapestry of website design and digital marketing. It's not merely about having a website; it's about crafting an immersive digital experience that captivates audiences and drives business growth. The Art of Business Website Design Your website is...
1
10541
by: Hystou | last post by:
Overview: Windows 11 and 10 have less user interface control over operating system update behaviour than previous versions of Windows. In Windows 11 and 10, there is no way to turn off the Windows Update option using the Control Panel or Settings app; it automatically checks for updates and installs any it finds, whether you like it or not. For most users, this new feature is actually very convenient. If you want to control the update process,...
0
9320
agi2029
by: agi2029 | last post by:
Let's talk about the concept of autonomous AI software engineers and no-code agents. These AIs are designed to manage the entire lifecycle of a software development project—planning, coding, testing, and deployment—without human intervention. Imagine an AI that can take a project description, break it down, write the code, debug it, and then launch it, all on its own.... Now, this would greatly impact the work of software developers. The idea...
0
6951
by: conductexam | last post by:
I have .net C# application in which I am extracting data from word file and save it in database particularly. To store word all data as it is I am converting the whole word file firstly in HTML and then checking html paragraph one by one. At the time of converting from word file to html my equations which are in the word document file was convert into image. Globals.ThisAddIn.Application.ActiveDocument.Select();...
0
5624
by: TSSRALBI | last post by:
Hello I'm a network technician in training and I need your help. I am currently learning how to create and manage the different types of VPNs and I have a question about LAN-to-LAN VPNs. The last exercise I practiced was to create a LAN-to-LAN VPN between two Pfsense firewalls, by using IPSEC protocols. I succeeded, with both firewalls in the same network. But I'm wondering if it's possible to do the same thing, with 2 Pfsense firewalls...
0
5789
by: adsilva | last post by:
A Windows Forms form does not have the event Unload, like VB6. What one acts like?
1
4421
by: 6302768590 | last post by:
Hai team i want code for transfer the data from one system to another through IP address by using C# our system has to for every 5mins then we have to update the data what the data is updated we have to send another system
3
3078
bsmnconsultancy
by: bsmnconsultancy | last post by:
In today's digital era, a well-designed website is crucial for businesses looking to succeed. Whether you're a small business owner or a large corporation in Toronto, having a strong online presence can significantly impact your brand's success. BSMN Consultancy, a leader in Website Development in Toronto offers valuable insights into creating effective websites that not only look great but also perform exceptionally well. In this comprehensive...

By using Bytes.com and it's services, you agree to our Privacy Policy and Terms of Use.

To disable or enable advertisements and analytics tracking please visit the manage ads & tracking page.