文本程序处理.ppt

1、Liqi Gao,Text Operations,Utilities,C/C+ Library Perl (Active Perl) Regular Expression Edit Plus / Ultra Edit Excel,C/C+ Language,Standard library: Read a line Remove a CR or LF Split a line,C+ Boost Library Case Conversion Trimming Replace Algorithm Finding Algorithm Split,C/C+: Read a Line,Though i

2、ts simple, its useful! Three methods:,C/C+: Remove CR/LF,Get a line under Windows and Linux platform,C/C+: Remove CR/LF (cont.),The noising CR Carriage Return,C/C+: Split a Line,Split a line by a specific character,C/C+: Split a Line (cont.),Split a line,C+ Boost: Case Conversion,to_upper: Convert a

3、 string to upper case to_lower: Convert a string to lower case,C+ Boost: Trimming - variable assignment statement print “Hello world!n”; printf “All %d of you!n”, $x;,- function calls (output statements),perltaste.pl: Greet the entire world.,Scalar Values,Numerical Values integer:5, “3”, 0, -307 flo

4、ating point: 6.2e9, -4022.33 hexadecimal/octal:0 x0d4f, 0477 NOTE: all numerical values stored as floating-point numbers (usu. “double” precision),String Values,Double-quoted: interpolates (replaces variable name/control character with its value) Single-quoted: no interpolation done (as-is) Quoting

5、operators: qq/, qw/, etc.,$day = “Monday”; “Happy Monday!n”Happy Monday! “Happy $date!n”Happy Monday! Happy Monday!nHappy Monday! Happy $date!nHappy $date!n,String Manipulation,Concatenation $dna1 = “ACTGCGTAGC”; $dna2 = “CTTGCTAT”; juxtapose in a string assignment or print statement $new_dna = “$dn

6、a1$dna2”; Use the concatenation operator . $new_dna = $dna1 . $dna2; Add segments serially using incremental concatenation: $new_dna = $dna1; $new_dna .= $dna2; (shorthand for: $new_dna = $new_dna . $dna2;),Substitution,DNA transcription: T U Substitution operator s/: $dna = “GATTACATACACTGTTCA”; $r

7、na = $dna; $rna = s/T/U/;# “GAUUACAUACACUGUUCA” Exercise: Start with $dna =“gattACataCACTgttca”; and do the same as above. Print out $rna to the screen.,transcribe.pl:,$dna =“gattACataCACTgttca”; $rna = $dna; $rna = s/T/U/g; print DNA: $dnan; print RNA: $rnan;,Does it do what you expect? If not, why

8、 not?,Patterns in substitution are case-sensitive! What can we do? Convert all letters to upper (or lower) case (preferred when possible) If we want to retain mixed case, use transliteration operator tr/ $rna = tr/tT/uU/;,Case conversion,$string = “acCGtGcaTGc”; Upper case: $dna = uc($string);# “ACCGTGCATGC” or $dna = uc $string; or $dna = “U$string”; Lower case: $dna = lc($string);# “accgtgcatgc” or $dna = “L$string”; Sentence case: $dna = ucfirst($string) # “Accgtgcatgc” or $dna = “uL$string”;,Per