{"id":53,"date":"2013-09-28T10:31:00","date_gmt":"2013-09-28T15:31:00","guid":{"rendered":"https:\/\/www.chrystalsander.com\/blog\/?p=53"},"modified":"2023-07-26T15:58:33","modified_gmt":"2023-07-26T20:58:33","slug":"lambda-expressions-an-introduction","status":"publish","type":"post","link":"https:\/\/www.chrystalsander.com\/blog\/?p=53","title":{"rendered":"Lambda Expressions : An Introduction"},"content":{"rendered":"
\n<\/div>\n
\nOne definition of a lambda, \u03bb<\/b><\/span><\/span>,<\/b><\/span>
\nis the eleventh letter of the Greek alphabet and also has a value of
\n30 in the Greek numerical system. Another common usage is in
\nfraternity and sororities. Wikipedia gives at least twenty different
\nuses of the Lambda. Personally, the most awesome is the use of the
\nlambda is in calculus with the second greatest use of the Lambda
\nbeing in computer science. With the introduction of LINQ, lambda
\nusage has not only soared in code usage but the context is also easier to
\nunderstand.<\/div>\n
\n<\/div>\n
\nPer MSDN<\/a>,
\n\u201cA lambda expression is an anonymous function that you can use to
\ncreate delegates or expression tree types. By using lambda
\nexpressions, you can write local functions that can be passed as
\narguments or returned as the value of function calls.\u201d To learn
\nmore about delegates, go <\/span>here<\/a>.
\n <\/span>\n<\/div>\n
\n
<\/span><\/div>\n
\nIn .NET, the most basic lambda
\nexpression can be recognized by its operator, \u201c=>\u201d, where
\ninput parameters are on the left side of the operator and either an
\nexpression or statement is on right side. For example, in the most
\nbasic expression below, a parameter, \u201cx\u201d is passed in and the
\nreturned result is the value of \u201cx\u201d squared:<\/div>\n
\n<\/div>\n
\nEXAMPLE #1 \u2013 Basic Expression
\nLambda :<\/b><\/div>\n
\n
<\/b><\/div>\n
\n \/\/Simple Expression
\nLambda:<\/span><\/span><\/span><\/span><\/span><\/div>\n
\ndelegate<\/span><\/span><\/span> <\/span><\/span><\/span>int<\/span><\/span><\/span> <\/span><\/span><\/span>del<\/span><\/span><\/span>(<\/span><\/span><\/span>int<\/span><\/span><\/span> i);<\/span><\/span><\/span><\/span><\/span><\/div>\n
\npublic<\/span><\/span><\/span> <\/span><\/span><\/span>static<\/span><\/span><\/span> <\/span><\/span><\/span>void<\/span><\/span><\/span> useDelegate()<\/span><\/span><\/span><\/span><\/span><\/div>\n
\n{<\/span><\/span><\/span><\/span><\/span><\/div>\n
\n    <\/span>del<\/span><\/span><\/span> d = x => x * x;<\/span><\/span><\/span><\/span><\/span><\/div>\n
\n    <\/span>int<\/span><\/span><\/span> intParam = d(5);<\/span><\/span><\/span><\/span><\/span><\/div>\n
\n    <\/span>Console<\/span><\/span><\/span>.WriteLine(<\/span><\/span><\/span>“intParam now has a value of {0}.”<\/span><\/span><\/span>, intParam);<\/span><\/span><\/span><\/span><\/span><\/div>\n
\n    <\/span>Console<\/span><\/span><\/span>.ReadLine();<\/span><\/span><\/span><\/span><\/span><\/div>\n
\n}<\/span><\/span><\/span><\/span><\/span><\/div>\n
\n\n<\/div>\n
\nResult:<\/b><\/div>\n
\n<\/div>\n
\n<\/a><\/div>\n
\n<\/div>\n
\n<\/div>\n
\n<\/div>\n
\nEXAMPLE #2 \u2013 Expression Lambda
\nwith multiple parameters:<\/b><\/div>\n
\n
<\/b><\/div>\n
\n\/\/Expression
\nLambda returning a bool:<\/span><\/span><\/span><\/span><\/span><\/div>\n
\ndelegate<\/span><\/span><\/span> <\/span><\/span><\/span>bool<\/span><\/span><\/span> <\/span><\/span><\/span>del2<\/span><\/span><\/span>(<\/span><\/span><\/span>int<\/span><\/span><\/span> i, <\/span><\/span><\/span>string<\/span><\/span><\/span> s);<\/span><\/span><\/span><\/span><\/span><\/div>\n
\npublic<\/span><\/span><\/span> <\/span><\/span><\/span>static<\/span><\/span><\/span> <\/span><\/span><\/span>void<\/span><\/span><\/span> useTwoVariables()<\/span><\/span><\/span><\/span><\/span><\/div>\n
\n{<\/span><\/span><\/span><\/span><\/span><\/div>\n
\n    <\/span>del2<\/span><\/span><\/span> d = (<\/span><\/span><\/span>int<\/span><\/span><\/span> x, <\/span><\/span><\/span>string<\/span><\/span><\/span> s) => s.Length > x;<\/span><\/span><\/span><\/span><\/span><\/div>\n
\n    <\/span>bool<\/span><\/span><\/span> val = d(5, <\/span><\/span><\/span>“ten”<\/span><\/span><\/span>);<\/span><\/span><\/span><\/span><\/span><\/div>\n
\n    <\/span>Console<\/span><\/span><\/span>.WriteLine(<\/span><\/span><\/span>“The bool value of the expression is : {0}”<\/span><\/span><\/span>, val);<\/span><\/span><\/span><\/span><\/span><\/div>\n
\n    <\/span>Console<\/span><\/span><\/span>.ReadLine();  <\/span><\/span><\/span><\/span><\/span><\/div>\n
\n}<\/span><\/span><\/span><\/span><\/span><\/div>\n
\n
<\/span><\/span><\/span><\/span><\/span><\/div>\n
\nResult:<\/b><\/div>\n
\n
<\/b><\/div>\n
\n<\/a><\/div>\n
\n
<\/b><\/div>\n
\n<\/div>\n
\n<\/div>\n
\nEXAMPLE #3 \u2013 Statement Lambda:<\/b><\/div>\n
\n
<\/b><\/div>\n
\n\/\/Statement
\nLambda using strings to create a message<\/span><\/span><\/span><\/span><\/span><\/div>\n
\ndelegate<\/span><\/span><\/span> <\/span><\/span><\/span>void<\/span><\/span><\/span> <\/span><\/span><\/span>CreateMessage<\/span><\/span><\/span>(<\/span><\/span><\/span>string<\/span><\/span><\/span> s);<\/span><\/span><\/span><\/span><\/span><\/div>\n
\npublic<\/span><\/span><\/span> <\/span><\/span><\/span>static<\/span><\/span><\/span> <\/span><\/span><\/span>void<\/span><\/span><\/span> useStrings()<\/span><\/span><\/span><\/span><\/span><\/div>\n
\n{<\/span><\/span><\/span><\/span><\/span><\/div>\n
\n    <\/span>CreateMessage<\/span><\/span><\/span> cStr = x => { <\/span><\/span><\/span>string<\/span><\/span><\/span> s = x + <\/span><\/span><\/span>” “<\/span><\/span><\/span> + <\/span><\/span><\/span>“is reigning MotoGP World Champion.”<\/span><\/span><\/span>; <\/span><\/span><\/span>Console<\/span><\/span><\/span>.WriteLine(s); };<\/span><\/span><\/span><\/span><\/span><\/div>\n
\n    cStr(<\/span><\/span><\/span>“Jorge Lorenzo, #99, “<\/span><\/span><\/span>);<\/span><\/span><\/span><\/span><\/span><\/div>\n
\n    <\/span>Console<\/span><\/span><\/span>.ReadLine();<\/span><\/span><\/span><\/span><\/span><\/div>\n
\n}<\/span><\/span><\/span><\/span><\/span><\/div>\n
\n
<\/span><\/span><\/span><\/span><\/span><\/div>\n
\nResult:<\/b><\/div>\n
\n
<\/b><\/div>\n
\n<\/div>\n
\n<\/a><\/div>\n
\n
<\/b><\/div>\n
\n<\/div>\n
\n\n<\/div>\n
\nEXAMPLE #3 \u2013 Using Lambda on
\nGenerics:<\/b><\/div>\n
\n\/\/Use the Query
\nOperator func on generic delegates<\/span><\/span><\/span><\/span><\/span><\/div>\n
\npublic<\/span><\/span><\/span> <\/span><\/span><\/span>delegate<\/span><\/span><\/span> TResult <\/span><\/span><\/span>Func<\/span><\/span><\/span><TArg0, TResult>(TArg0 arg0);<\/span><\/span><\/span><\/span><\/span><\/div>\n
\npublic<\/span><\/span><\/span> <\/span><\/span><\/span>static<\/span><\/span><\/span> <\/span><\/span><\/span>void<\/span><\/span><\/span> useFunc()<\/span><\/span><\/span><\/span><\/span><\/div>\n
\n{<\/span><\/span><\/span><\/span><\/span><\/div>\n
\n    <\/span>int<\/span><\/span><\/span> a = 15;<\/span><\/span><\/span><\/span><\/span><\/div>\n
\n    <\/span>Func<\/span><\/span><\/span><<\/span><\/span><\/span>int<\/span><\/span><\/span>, <\/span><\/span><\/span>int<\/span><\/span><\/span>> func = x => x \/ x;<\/span><\/span><\/span><\/span><\/span><\/div>\n
\n    <\/span>Console<\/span><\/span><\/span>.WriteLine(<\/span><\/span><\/span>“Result is {0}”<\/span><\/span><\/span>, func(a));<\/span><\/span><\/span><\/span><\/span><\/div>\n
\n    <\/span>Console<\/span><\/span><\/span>.ReadLine();<\/span><\/span><\/span><\/span><\/span><\/div>\n
\n}<\/span><\/span><\/span><\/span><\/span><\/div>\n
\n
<\/span><\/span><\/span><\/span><\/span><\/div>\n

<\/p>\n

\n<\/div>\n

<\/p>\n

\nResult:<\/b><\/div>\n
\n
<\/b><\/div>\n
\n<\/a><\/div>\n
\n
<\/b><\/div>\n
\n
<\/b><\/div>\n","protected":false},"excerpt":{"rendered":"

One definition of a lambda, \u03bb, is the eleventh letter of the Greek alphabet and also has a value of 30 in the Greek numerical system. Another common usage is in fraternity and sororities. Wikipedia gives at least twenty different uses of the Lambda. Personally, the most awesome is the use of the lambda is … Continue reading “Lambda Expressions : An Introduction”<\/span><\/a><\/p>\n","protected":false},"author":2,"featured_media":0,"comment_status":"open","ping_status":"closed","sticky":false,"template":"","format":"standard","meta":{"footnotes":""},"categories":[31,33],"tags":[83],"_links":{"self":[{"href":"https:\/\/www.chrystalsander.com\/blog\/index.php?rest_route=\/wp\/v2\/posts\/53"}],"collection":[{"href":"https:\/\/www.chrystalsander.com\/blog\/index.php?rest_route=\/wp\/v2\/posts"}],"about":[{"href":"https:\/\/www.chrystalsander.com\/blog\/index.php?rest_route=\/wp\/v2\/types\/post"}],"author":[{"embeddable":true,"href":"https:\/\/www.chrystalsander.com\/blog\/index.php?rest_route=\/wp\/v2\/users\/2"}],"replies":[{"embeddable":true,"href":"https:\/\/www.chrystalsander.com\/blog\/index.php?rest_route=%2Fwp%2Fv2%2Fcomments&post=53"}],"version-history":[{"count":1,"href":"https:\/\/www.chrystalsander.com\/blog\/index.php?rest_route=\/wp\/v2\/posts\/53\/revisions"}],"predecessor-version":[{"id":242,"href":"https:\/\/www.chrystalsander.com\/blog\/index.php?rest_route=\/wp\/v2\/posts\/53\/revisions\/242"}],"wp:attachment":[{"href":"https:\/\/www.chrystalsander.com\/blog\/index.php?rest_route=%2Fwp%2Fv2%2Fmedia&parent=53"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/www.chrystalsander.com\/blog\/index.php?rest_route=%2Fwp%2Fv2%2Fcategories&post=53"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/www.chrystalsander.com\/blog\/index.php?rest_route=%2Fwp%2Fv2%2Ftags&post=53"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}