Physical Design: strings

Strings

A string is a sequence of letters, it always need not be enclosed in the quotes until you use some white spaces in between the words. Tcl is a string based language it provides rich set of operations on strings.

Examples :

set str1 one

set str2 "two three"

set str3 I\ need\ not\ enclose\ this\ in\ quotes

Example :

	set str1 Tcl
	set str2 "Tcl programmer"
	set str3 tcl
	#The string compare command compares strings character by character. If it finds that the first characters of both strings are equal,
	#it continues with the second character, until the end. It returns 0 if the strings are equal and -1
	#if a non-matching character in the first string is located in the ASCII table before the character of the second string.
	#The 1 number is returned if the non-matching character of the first string is located after the character of the second string.
	puts [string compare $str1 $str2 ] ; #output is -1
	puts [string compare -length 3 $str3 $str2 ] ; #output is 1
	puts [string compare -length 3 $str1 $str2 ] ; #output is 0, it checks first 3 letters in the string

	#string equal can be used to compare strings, it returns 1 if they are true else 0 for false. It checks for case
	puts [string equal $str2 $str3 ] ; #output is 0
	puts [string equal -length 3 $str2 $str3 ] ; #output is 1, it checks first 3 letters in the string

	puts [string length $str1] ; #output is 3

	puts [string match Tcl* $str2] ; #global expression
	puts [string toupper $str1] ; #Output : TCL
	puts [string tolower $str1]; #Output : tcl
	#string totitle #it will convert the starting letter of string to uppercase
	puts [string totitle $str3]; # Output : Tcl
	#To get the last letter of the string
	puts [string index $str1 end]

	#to get range of letters
	puts [string range $str2 2 5]; #output : l pr


	puts [string reverse $str2]
	#Output:remmargorp lcT

view raw strings.tcl hosted with ❤ by GitHub

Physical Design