Regular expression matching

By default, any character or metacharacter in a regular expression matches exactly once. By placing a quantifier after the character, Perl can match a character a specific number of times or a range of times. The simplest type of quantifier is M>, which tells Perl to match the pattern exactly M times. Using this notation, the ZIP+4 regular expression could be rewritten as... 

When a string successfully matches a regular expression, any portions of the expression that are contained within parentheses are extracted and placed into the automatic variables 1, 2, 3, and so forth. The extraction works from left to right and only happens if the entire regular expression matches. 

It should be clear that a simple classifier based on token observations will only be sufficient in the simplest of cases. If we take the case of cardinal numbers, we see that it would be absurd to list the possible tokens that a cardinal class can give rise to the list would literally be infinite. To handle this, we make use of specialist sub-classifiers which use regular expression generators to identify likely tokens from a given class. One way of doing this is to run regular expression matches on tokens and use the result of this as a feature in the classifier itself. So we might have... 

Closed classes can be enumerated, open classes require regular expression matches. 

The majority of prosite documentation refers to motifs rather than profiles. The motifs are less sensitive than profiles and do not provide statistical scores. The motifs correspond to active sites and other important functional sites in proteins. The motifs are expressed as regular expressions that can be used to detect matching proteins in the database. An example of a motif from Prosite would be the /V-glycosylation motif,... 

Regular expressions specify a set of character strings and are useful for pattern matching. In the context of an MSA, regular expressions can be used to define,... 

A regular expression (sometimes abbreviated regex) is a way for a computer user or programmer to express how a computer program should look for a specified pattern in text and then what the program is to do when each pattern match is found (www.whatis.com). 

Finally, the nvalue column of the vla4.property table can be populated when possible. This column stores the numerical value of the property. Since not all values are numerical, this column may have null entries. The purpose is to enable efficient use of numerical data when appropriate, for example, to select by value, sort, apply mathematical functions, etc. The following SQL will update the nvalue column when possible with a numeric value. The tilde operator in the where selects text values that match the regular expression. The expression shown here allows integers, decimal values, and scientific notation using E or e for the exponent, for example 6.023E23. 

R.F. Sewell and R. Durbin, Method of calculation of probability of matching a bounded regular expression in a random data string, J. Comp. Biol, 1995, 2(1), 25-31. 

Regular expression patterns are delimited by forward slashes. The simplest ones contain a sequence of normal characters that must match somewhere within the body of a string. The EcoR I-site detector is one such example. Regular expressions are much more powerful than this, however. For example, square brackets can be used to specify a set of alternative characters in the manner shown here ... 

For example, to match a ZIP+4 format ZIP code, the required regular expression would be written as follows ... 

For a regular expression to match a metacharacter literally, it must be preceded by a backslash. For example, to match DNA sequence IDs of the form M58200.2, where a dot is used literally, the regular expression should be written... 

Parentheses can be used to group parts of a regular expression, and then a quantifier can be applied to the entire group. For example, this regular expression will match normal five-digit ZIP codes as well as the ZIP -i- 4 form ... 

Not only are regular expressions good for detecting patterns in text, but they can be used to extract matching portions of the text as well. To see how this might be useful, consider a PASTA description line like this one ... 

Once this is done, the contents of phenotype are compared to a regnlar expression. The regular expression is a series of alternatives, separated by the I character. Any phenotype that contains any of the strings listed will prodnce a match. Notice that some of the keywords have been shortened to rednce the length of the expression, as well as pull in some terms that may not have been anticipated. For example, paraly will match both paralysis and paralyzed, withont mnch... 

To speed up the inference procedure, a tree search is performed instead of a linear search while matching an observation to a regular expression. The tree search uses an automatically generated hierarchical search tree. The original archetypes form the leaves of the tree, while inner nodes are created based on the similarity between the activities based on the nine dimensions. 

String-based CC e.g., for verifying whether value nodes match a certain regular expression (sh pattern). 

In the two infants a 30% ex vivo transfection efficiency was achieved. Following the re-introduction of the stem cells, each patient s blood was analyzed on a regular basis for receptor expression in appropriate cell types, and for immunological function. After 10 months, the results showed that T- and NK-cell counts were comparable to matched normal infants. Moreover the T and NK cells were found to be completely functional. 

Many words in regular usage, as well as many technical terms, have two or more acceptable spellings. The following list gives recommended spellings and capitalizations, where appropriate, for some terms not found in easily accessible dictionaries, words often misspelled, common expressions, and words for which the ACS preference may not match your dictionary s. 

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