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< h2 id = "lazymatching" > Lazy matching:< / h2 >
< p > As we have seen, the default nature of quantifiers is greedy, so it will match as many characters as possible.< / p >
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< iframe scrolling = "no" style = "position: absolute; top: -9999em; visibility: hidden;" onload = "this.style.position='static'; this.style.visibility='visible';" src = "https://regexr.com/4vtqc" class = "embed" > < / iframe >
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< p > To make it lazy, we use < code > ?< / code > quantifier, which turns the regex engine to match as less characters as possible which satisfies the expression.< / p >
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< iframe scrolling = "no" style = "position: absolute; top: -9999em; visibility: hidden;" onload = "this.style.position='static'; this.style.visibility='visible';" src = "https://regexr.com/4vtqf" class = "embed" > < / iframe >
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< p > Below is a table showing lazy version of all quantifiers:< / p >
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< td > Quantifier< / td >
< td > Lazy version< / td >
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< tr >
< td > {n,m}< / td >
< td > {n,m}?< / td >
< / tr >
< tr >
< td > {n,}< / td >
< td > {n,}?< / td >
< / tr >
< tr >
< td > +< / td >
< td > +?< / td >
< / tr >
< tr >
< td > *< / td >
< td > *?< / td >
< / tr >
< tr >
< td > ?< / td >
< td > ??< / td >
< / tr >
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< p > So, now we can match html tags as below:< / p >
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< iframe scrolling = "no" style = "position: absolute; top: -9999em; visibility: hidden;" onload = "this.style.position='static'; this.style.visibility='visible';" src = "https://regexr.com/4vtqr" class = "embed" > < / iframe >
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< p > < strong > Problem< / strong > < / p >
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< p > Find an expression to match < code > href="url"< / code > in html file. Note that url can be anything, like < code > https://xyz.com< / code > , < code > http://abc.io/app< / code > , < code > https://cde.org< / code > .< / p >
< p > Answer: < code > href=".*?"< / code > < / p >
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< iframe scrolling = "no" style = "position: absolute; top: -9999em; visibility: hidden;" onload = "this.style.position='static'; this.style.visibility='visible';" src = "https://regexr.com/4vu96" class = "embed" > < / iframe >
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< / li >
< li >
What will be the match for expression < code > \w+? \w+?< / code > in < code > abc cde, 123 456< / code > .
< br > Answer: < code > 123 4< / code > and < code > abc d< / code >
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< iframe scrolling = "no" style = "position: absolute; top: -9999em; visibility: hidden;" onload = "this.style.position='static'; this.style.visibility='visible';" src = "https://regexr.com/4vuek" class = "embed" > < / iframe >
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< p > We will see how to extract things(like, urls) from the text using regex, in the "group and capturing" concept.< / p >
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