Welcome!

Microsoft Cloud Authors: Pat Romanski, Jnan Dash, Andreas Grabner, Lori MacVittie, Jim Kaskade

Blog Feed Post

Improving .NET Application Performance Part 12: String Operations

In our previous article in this series we discussed Iteration and Looping. In this article we’ll focus on optimizing string operations.

The .NET Framework provides the System.String data type to represent a string. Intensive string manipulation can degrade performance. Every time you perform an operation to change string data, the original string in memory is discarded for later garbage collection and a new one is created to hold the new string data. Also note that the String type is a reference type, so the contents of the string are stored on the managed heap. As a result, strings must be garbage collected to be cleaned up.

This section summarizes recommendations you should consider when working with strings.

Avoid Inefficient String Concatenation

Excessive string concatenation results in many allocation and deallocation operations, because each time you perform an operation to change the string, a new one is created and the old one is subsequently collected by the garbage collector.

·         If you concatenate string literals, the compiler concatenates them at compile time.

//’Hello’ and ‘world’ are string literals

String str = “Hello” + “world”;

·         If you concatenate nonliteral strings, CLR concatenates them at run time. So using the + operator creates multiple strings objects in the managed heap.

·         Use StringBuilder for complex string manipulations and when you need to concatenate strings multiple times.

// using String and ‘+’ to append

String str = “Some Text”;

for ( … loop several times to build the string …) {

  str = str + ” additional text “;

}

// using String and .Append method to append

StringBuilder strBuilder = new StringBuilder(“Some Text “);

for ( … loop several times to build the string …) {

  strBuilder.Append(” additional text “);

}

Use + When the Number of Appends Is Known

If you know the number of appends to be made and you are concatenating the strings in one shot, prefer the + operator for concatenation.

String str = str1+str2+str3;

 

If you concatenate the strings in a single expression, only one call to String.Concat needs to be made. It results in no temporary strings (for partial combinations of the strings to be concatenated).

Avoid should not be using + on strings inside a loop or for multiple iterations. Use StringBuilder instead.

Use StringBuilder When the Number of Appends Is Unknown

If you do not know the number of appends to be made, which might be the case when iterating through a loop or building dynamic SQL queries, use the StringBuilder class as shown in the following code sample.

for (int i=0; i< Results.Count; i++)

{

  StringBuilder.Append (Results[i]);

}

 

The StringBuilder class starts with a default initial capacity of 16. Strings less than the initial capacity are stored in the StringBuilder object. The initial capacity of the buffer can be set by using the following overloaded constructor.

public StringBuilder (int capacity);

You can continue to concatenate without additional allocations until you consume the preallocated buffer. As a result, using a StringBuilder object is often more efficient than using String objects for concatenation. If you concatenate further, the StringBuilder class creates a new buffer of the size equal to double the current capacity.

So if you start with a StringBuilder of size 16 and exceed the limit, the StringBuilder allocates a new buffer of size 32 and copies the old string to the new buffer. The old buffer is inaccessible and becomes eligible for garbage collection.

You should try to set the initial capacity of the StringBuilder to an optimum value to reduce the cost of new allocations. To determine the optimum value for your case, the best way is to track the memory consumption by using the CLR profiler. For more information about how to use CLR profiler, see “How To: Use CLR Profiler” in the “How To” section of this guide.

Treat StringBuilder as an Accumulator

You can treat StringBuilder as an accumulator or reusable buffer. This helps avoid the allocations of temporary strings during multiple append iterations. Some of the scenarios where this helps are as follows:

  • Concatenating strings. You should always prefer the following approach to string concatenation when using StringBuilder.

StringBuilder sb;

sb.Append(str1);

sb.Append(str2);

Use the preceding code rather than the following.

sb.Append(str1+str2);

 

This is because you do not need to make the temporary str1+str2 to append str1 and then str2.

·         Concatenating the strings from various functions.

An example of this is shown in the following code sample.

StringBuilder sb;

sb.Append(f1());

sb.Append(f2());

sb.Append(f3());

The preceding code snippet results in temporary string allocations for the return values by the functions f1 (…), f2 (), f3 (). You can avoid these temporary allocations by using the following pattern.

void f1( sb,);

void f2( sb,);

void f3( sb,);

In this case, the StringBuilder instance is directly passed as an input parameter to the methods. sb.Append is directly called in the function body, which avoids the allocation of temporary strings.

Use the Overloaded Compare Method for Case-Insensitive String Comparisons

Carefully consider how you perform case-insensitive string comparisons. Avoid using ToLower as shown in the following code because you end up creating temporary string objects.

// Bad way for insensitive operations because ToLower creates temporary

strings

String str=”New York”;

String str2 = “New york”;

if (str.ToLower()==str2.ToLower())

  // do something

The more efficient way to perform case-insensitive string comparisons is to use the Compare method.

str.Compare(str,str2,false);

 

The String.Compare method uses the info in the CultureInfo.CompareInfo property to compare culture-sensitive strings.

Share Now:del.icio.usDiggFacebookLinkedInBlinkListDZoneGoogle BookmarksRedditStumbleUponTwitterRSS

Read the original blog entry...

More Stories By Hovhannes Avoyan

Hovhannes Avoyan is the CEO of PicsArt, Inc.,

@ThingsExpo Stories
IoT is at the core or many Digital Transformation initiatives with the goal of re-inventing a company's business model. We all agree that collecting relevant IoT data will result in massive amounts of data needing to be stored. However, with the rapid development of IoT devices and ongoing business model transformation, we are not able to predict the volume and growth of IoT data. And with the lack of IoT history, traditional methods of IT and infrastructure planning based on the past do not app...
"LinearHub provides smart video conferencing, which is the Roundee service, and we archive all the video conferences and we also provide the transcript," stated Sunghyuk Kim, CEO of LinearHub, in this SYS-CON.tv interview at @ThingsExpo, held November 1-3, 2016, at the Santa Clara Convention Center in Santa Clara, CA.
With major technology companies and startups seriously embracing IoT strategies, now is the perfect time to attend @ThingsExpo 2016 in New York. Learn what is going on, contribute to the discussions, and ensure that your enterprise is as "IoT-Ready" as it can be! Internet of @ThingsExpo, taking place June 6-8, 2017, at the Javits Center in New York City, New York, is co-located with 20th Cloud Expo and will feature technical sessions from a rock star conference faculty and the leading industry p...
The 20th International Cloud Expo has announced that its Call for Papers is open. Cloud Expo, to be held June 6-8, 2017, at the Javits Center in New York City, brings together Cloud Computing, Big Data, Internet of Things, DevOps, Containers, Microservices and WebRTC to one location. With cloud computing driving a higher percentage of enterprise IT budgets every year, it becomes increasingly important to plant your flag in this fast-expanding business opportunity. Submit your speaking proposal ...
"There's a growing demand from users for things to be faster. When you think about all the transactions or interactions users will have with your product and everything that is between those transactions and interactions - what drives us at Catchpoint Systems is the idea to measure that and to analyze it," explained Leo Vasiliou, Director of Web Performance Engineering at Catchpoint Systems, in this SYS-CON.tv interview at 18th Cloud Expo, held June 7-9, 2016, at the Javits Center in New York Ci...
Discover top technologies and tools all under one roof at April 24–28, 2017, at the Westin San Diego in San Diego, CA. Explore the Mobile Dev + Test and IoT Dev + Test Expo and enjoy all of these unique opportunities: The latest solutions, technologies, and tools in mobile or IoT software development and testing. Meet one-on-one with representatives from some of today's most innovative organizations
20th Cloud Expo, taking place June 6-8, 2017, at the Javits Center in New York City, NY, will feature technical sessions from a rock star conference faculty and the leading industry players in the world. Cloud computing is now being embraced by a majority of enterprises of all sizes. Yesterday's debate about public vs. private has transformed into the reality of hybrid cloud: a recent survey shows that 74% of enterprises have a hybrid cloud strategy.
SYS-CON Events announced today that Super Micro Computer, Inc., a global leader in Embedded and IoT solutions, will exhibit at SYS-CON's 20th International Cloud Expo®, which will take place on June 7-9, 2017, at the Javits Center in New York City, NY. Supermicro (NASDAQ: SMCI), the leading innovator in high-performance, high-efficiency server technology, is a premier provider of advanced server Building Block Solutions® for Data Center, Cloud Computing, Enterprise IT, Hadoop/Big Data, HPC and E...
SYS-CON Events announced today that Linux Academy, the foremost online Linux and cloud training platform and community, will exhibit at SYS-CON's 20th International Cloud Expo®, which will take place on June 6-8, 2017, at the Javits Center in New York City, NY. Linux Academy was founded on the belief that providing high-quality, in-depth training should be available at an affordable price. Industry leaders in quality training, provided services, and student certification passes, its goal is to c...
WebRTC is the future of browser-to-browser communications, and continues to make inroads into the traditional, difficult, plug-in web communications world. The 6th WebRTC Summit continues our tradition of delivering the latest and greatest presentations within the world of WebRTC. Topics include voice calling, video chat, P2P file sharing, and use cases that have already leveraged the power and convenience of WebRTC.
WebRTC sits at the intersection between VoIP and the Web. As such, it poses some interesting challenges for those developing services on top of it, but also for those who need to test and monitor these services. In his session at WebRTC Summit, Tsahi Levent-Levi, co-founder of testRTC, reviewed the various challenges posed by WebRTC when it comes to testing and monitoring and on ways to overcome them.
"A lot of times people will come to us and have a very diverse set of requirements or very customized need and we'll help them to implement it in a fashion that you can't just buy off of the shelf," explained Nick Rose, CTO of Enzu, in this SYS-CON.tv interview at 18th Cloud Expo, held June 7-9, 2016, at the Javits Center in New York City, NY.
Every successful software product evolves from an idea to an enterprise system. Notably, the same way is passed by the product owner's company. In his session at 20th Cloud Expo, Oleg Lola, CEO of MobiDev, will provide a generalized overview of the evolution of a software product, the product owner, the needs that arise at various stages of this process, and the value brought by a software development partner to the product owner as a response to these needs.
WebRTC services have already permeated corporate communications in the form of videoconferencing solutions. However, WebRTC has the potential of going beyond and catalyzing a new class of services providing more than calls with capabilities such as mass-scale real-time media broadcasting, enriched and augmented video, person-to-machine and machine-to-machine communications. In his session at @ThingsExpo, Luis Lopez, CEO of Kurento, introduced the technologies required for implementing these idea...
The WebRTC Summit New York, to be held June 6-8, 2017, at the Javits Center in New York City, NY, announces that its Call for Papers is now open. Topics include all aspects of improving IT delivery by eliminating waste through automated business models leveraging cloud technologies. WebRTC Summit is co-located with 20th International Cloud Expo and @ThingsExpo. WebRTC is the future of browser-to-browser communications, and continues to make inroads into the traditional, difficult, plug-in web co...
The Internet of Things will challenge the status quo of how IT and development organizations operate. Or will it? Certainly the fog layer of IoT requires special insights about data ontology, security and transactional integrity. But the developmental challenges are the same: People, Process and Platform. In his session at @ThingsExpo, Craig Sproule, CEO of Metavine, demonstrated how to move beyond today's coding paradigm and shared the must-have mindsets for removing complexity from the develop...
While not quite mainstream yet, WebRTC is starting to gain ground with Carriers, Enterprises and Independent Software Vendors (ISV’s) alike. WebRTC makes it easy for developers to add audio and video communications into their applications by using Web browsers as their platform. But like any market, every customer engagement has unique requirements, as well as constraints. And of course, one size does not fit all. In her session at WebRTC Summit, Dr. Natasha Tamaskar, Vice President, Head of C...
Who are you? How do you introduce yourself? Do you use a name, or do you greet a friend by the last four digits of his social security number? Assuming you don’t, why are we content to associate our identity with 10 random digits assigned by our phone company? Identity is an issue that affects everyone, but as individuals we don’t spend a lot of time thinking about it. In his session at @ThingsExpo, Ben Klang, Founder & President of Mojo Lingo, discussed the impact of technology on identity. Sho...
DevOps is being widely accepted (if not fully adopted) as essential in enterprise IT. But as Enterprise DevOps gains maturity, expands scope, and increases velocity, the need for data-driven decisions across teams becomes more acute. DevOps teams in any modern business must wrangle the ‘digital exhaust’ from the delivery toolchain, "pervasive" and "cognitive" computing, APIs and services, mobile devices and applications, the Internet of Things, and now even blockchain. In this power panel at @...
With all the incredible momentum behind the Internet of Things (IoT) industry, it is easy to forget that not a single CEO wakes up and wonders if “my IoT is broken.” What they wonder is if they are making the right decisions to do all they can to increase revenue, decrease costs, and improve customer experience – effectively the same challenges they have always had in growing their business. The exciting thing about the IoT industry is now these decisions can be better, faster, and smarter. Now ...