The Ring programming language version 1.2 book - Part 12 of 84
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This document describes string manipulation functions in Ring including: - Getting the length of a string with len() - Converting case with upper() and lower() - Accessing characters with indexing and for loops - Extracting substrings with left() and right() - Trimming spaces with trim() - Copying strings with copy() - Counting lines with lines()
![Ring Documentation, Release 1.2
Example:
aList = ["one","two"]
add(aList,"three")
see aList
Also we can do that using the + operator.
Syntax:
List + item
Example:
aList = 1:10 # create list contains numbers from 1 to 10
aList + 11 # add number 11 to the list
see aList # print the list
21.3 Get List Size
We can get the list size using the len() function
Syntax:
Len(List)
Example:
aList = 1:20 see len(aList) # print 20
21.4 Delete Item From List
To delete an item from the list, we can use the del() function
Syntax:
del(list,index)
Example:
aList = ["one","two","other","three"]
Del(aList,3) # delete item number three
see aList # print one two three
21.5 Get List Item
To get an item from the list, we uses the next syntax
List[Index]
Example:
aList = ["Cairo","Riyadh"]
see "Egypt : " + aList[1] + nl +
"KSA : " + aList[2] + nl
21.3. Get List Size 90](https://image.slidesharecdn.com/111ringring-170217110652/85/The-Ring-programming-language-version-1-2-book-Part-12-of-84-1-320.jpg)
![Ring Documentation, Release 1.2
21.6 Set List Item
To set the value of an item inside the list, we can use the next syntax
List[Index] = Expression
Example:
aList = list(3) # create list contains three items
aList[1] = "one" aList[2] = "two" aList[3] = "three"
see aList
21.7 Search
To find an item inside the list we can use the find() function
Syntax:
Find(List,ItemValue) ---> Item Index
Find(List,ItemValue,nColumn) ---> Search in nColumn, returns the Item Index
Find(List,ItemValue,nColumn,cAttribute) ---> Item Index
Example:
aList = ["one","two","three","four","five"]
see find(aList,"three") # print 3
Example:
mylist = [["one",1],
["two",2],
["three",3]]
see find(mylist,"two",1) + nl # print 2
see find(mylist,2,2) + nl # print 2
Also we can use the binarysearch() function to search in sorted list.
Syntax:
BinarySearch(List,ItemValue) ---> Item Index
BinarySearch(List,ItemValue,nColumn) ---> Search in nColumn, returns the Item Index
Example:
aList = ["one","two","three","four","five"]
aList = sort(aList)
see binarysearch(aList,"three")
Output:
five
four
one
three
two
4
21.6. Set List Item 91](https://image.slidesharecdn.com/111ringring-170217110652/85/The-Ring-programming-language-version-1-2-book-Part-12-of-84-2-320.jpg)
![Ring Documentation, Release 1.2
21.8 Sort
We can sort the list using the sort() function.
Syntax:
Sort(List) ---> Sorted List
Sort(List,nColumn) ---> Sorted List based on nColumn
Sort(List,nColumn,cAttribute) ---> Sorted List based on Object Attribute
Example:
aList = [10,12,3,5,31,15]
aList = sort(aList) see aList # print 3 5 10 12 15 31
We can sort list of strings
Example:
mylist = ["mahmoud","samir","ahmed","ibrahim","mohammed"]
see mylist # print list before sorting
mylist = sort(mylist) # sort list
see "list after sort"+nl
see mylist # print ahmed ibrahim mahmoud mohammed samir
We can sort a list based on a specific column.
Example:
aList = [ ["mahmoud",15000] ,
["ahmed", 14000 ] ,
["samir", 16000 ] ,
["mohammed", 12000 ] ,
["ibrahim",11000 ] ]
aList2 = sort(aList,1)
see aList2
Output:
ahmed
14000
ibrahim
11000
mahmoud
15000
mohammed
12000
samir
16000
21.9 Reverse
We can reverse a list using the reverse() function.
Syntax:
21.8. Sort 92](https://image.slidesharecdn.com/111ringring-170217110652/85/The-Ring-programming-language-version-1-2-book-Part-12-of-84-3-320.jpg)
![Ring Documentation, Release 1.2
Reverse(List) ---> Reversed List
Example:
aList = [10,20,30,40,50]
aList = reverse(aList)
see aList # print 50 40 30 20 10
21.10 Insert Items
To insert an item in the list we can use the insert() function.
Syntax:
Insert(List,Index,Item)
The inserted item will be AFTER the Index
Example:
aList = ["A","B","D","E"]
insert(aList,2,"C") # Inserts AFTER Index 2, "C" into Position 3
see aList # print A B C D E
21.11 Nested Lists
The list may contain other lists
Example:
aList = [ 1 , [10,20,30] , 5 , [100,1000,5000] ]
aList2 = [
"one","two",
[3,4],
[20,30], ["three",
"four",
"five",[100,200,300]
]
]
see aList[2] # print 10 20 30
see aList[4][3] + nl # print 5000
see aList2[5][2] + nl # print four
see aList2[5][4][3] # print 300
21.12 Copy Lists
We can copy lists (including nested lists) using the Assignment operator.
Example:
21.10. Insert Items 93](https://image.slidesharecdn.com/111ringring-170217110652/85/The-Ring-programming-language-version-1-2-book-Part-12-of-84-4-320.jpg)
![Ring Documentation, Release 1.2
aList = [
"one","two",
[3,4],
[20,30], ["three",
"four",
"five",[100,200,300]
]
]
aList2 = aList # Copy aList to aList2
aList2[5] = "other" # modify item number five
see aList2[5] + nl # print other
see aList[5] # print three four five 100 200 300
21.13 First-class lists
Lists are first-class citizens where we can store lists in variables, pass lists to functions, and return lists from functions.
Example:
aList = duplicate( [1,2,3,4,5] )
see aList[10] + nl # print 5
see mylist() # print 10 20 30 40 50
func duplicate list
nMax = len(list)
for x = 1 to nMax
list + list[x]
next
return list
func mylist return [10,20,30,40,50]
21.14 Using Lists during definition
We can use the list items while we are defining the list for the first time.
Example:
aList = [ [1,2,3,4,5] , aList[1] , aList[1] ]
see aList # print 1 2 3 4 5 1 2 3 4 5 1 2 3 4 5
21.15 Passing Lists to Functions
Lists are passed to functions by reference, This means that the called function will work on the same list and can
modify it.
Example:
func main
aList = [1,2,3,4,5] # create list, local in function main
21.13. First-class lists 94](https://image.slidesharecdn.com/111ringring-170217110652/85/The-Ring-programming-language-version-1-2-book-Part-12-of-84-5-320.jpg)
![Ring Documentation, Release 1.2
myfunc(aList) # call function, pass list by reference
see aList # print 1 2 3 4 5 6 7 8 9 10
func myfunc list
list + [6,7,8,9,10]
21.16 Access List Items by String Index
Instead of using numbers to determine the item index when we get item value or set item value, We can access items
using string index if the item is a list contains two items and the first item is a string.
Example:
aList = [ ["one",1] , ["two",2] , ["three",3] ]
see aList["one"] + nl +
aList["two"] + nl +
aList["three"] # print 1 2 3
This type of lists can be defined in a better syntax using the : and = operators.
Example:
aList = [ :one = 1 , :two = 2 , :three = 3 ]
see aList["one"] + nl +
aList["two"] + nl +
aList["three"] + nl # print 1 2 3
see aList[1] # print one 1
Tip: using : before identifier (one word) means literal
Note: using = inside list definition create a list of two items where the first item is the left side and the second item is
the right side.
We can add new items to the list using the string index
Example:
aList = []
aList["Egypt"] = "Cairo"
aList["KSA"] = "Riyadh"
see aList["Egypt"] + nl + # print Cairo
aList["KSA"] + nl # print Riyadh
21.17 Passing Parameters Using List
This type of lists is very good for passing parameters to functions Where the order of parameters will not be important
(we can change the order).
Also some parameters maybe optional.
Example:
21.16. Access List Items by String Index 95](https://image.slidesharecdn.com/111ringring-170217110652/85/The-Ring-programming-language-version-1-2-book-Part-12-of-84-6-320.jpg)
![Ring Documentation, Release 1.2
myconnect ( [ :server = "myserver.com" , :port = 80 ,
:username = "mahmoud" , :password = "password" ] )
func myconnect mypara
# print connection details
see "User Name : " + mypara[:username] + nl +
"Password : " + mypara[:password] + nl +
"Server : " + mypara[:server] + nl +
"Port : " + mypara[:port]
21.17. Passing Parameters Using List 96](https://image.slidesharecdn.com/111ringring-170217110652/85/The-Ring-programming-language-version-1-2-book-Part-12-of-84-7-320.jpg)
![Ring Documentation, Release 1.2
22.4 Access String Letters
We can access a letter inside a string by the letter index
Syntax:
string[index] ---> get string letter
string[index] = letter # set string letter
Example:
# print user name letter by letter (each letter in new line)
See "Hello, Enter your name : " give cName
for x = 1 to len(cName)
see nl + cName[x]
next
We can use for in to get string letters.
Example:
# print user name letter by letter (each letter in new line)
See "Hello, Enter your name : " give cName
for x in cName
see nl + x
next
We can modify the string letters
Example:
# convert the first letter to UPPER case
See "Enter your name : " give cName
cName[1] = upper(cName[1])
see "Hello " + cName
22.5 Left() Function
We can get a specified number of characters from a string using the Left() function.
The starting position is 1.
Syntax:
Left(string,count)
Example:
see left("Hello World!",5) # print Hello
22.6 Right() Function
We can get a specified number of characters from a string using the Right() function.
22.4. Access String Letters 98](https://image.slidesharecdn.com/111ringring-170217110652/85/The-Ring-programming-language-version-1-2-book-Part-12-of-84-9-320.jpg)
The Ring programming language version 1.2 book - Part 12 of 84
- 1. Ring Documentation, Release 1.2 Example: aList = ["one","two"] add(aList,"three") see aList Also we can do that using the + operator. Syntax: List + item Example: aList = 1:10 # create list contains numbers from 1 to 10 aList + 11 # add number 11 to the list see aList # print the list 21.3 Get List Size We can get the list size using the len() function Syntax: Len(List) Example: aList = 1:20 see len(aList) # print 20 21.4 Delete Item From List To delete an item from the list, we can use the del() function Syntax: del(list,index) Example: aList = ["one","two","other","three"] Del(aList,3) # delete item number three see aList # print one two three 21.5 Get List Item To get an item from the list, we uses the next syntax List[Index] Example: aList = ["Cairo","Riyadh"] see "Egypt : " + aList[1] + nl + "KSA : " + aList[2] + nl 21.3. Get List Size 90
- 2. Ring Documentation, Release 1.2 21.6 Set List Item To set the value of an item inside the list, we can use the next syntax List[Index] = Expression Example: aList = list(3) # create list contains three items aList[1] = "one" aList[2] = "two" aList[3] = "three" see aList 21.7 Search To find an item inside the list we can use the find() function Syntax: Find(List,ItemValue) ---> Item Index Find(List,ItemValue,nColumn) ---> Search in nColumn, returns the Item Index Find(List,ItemValue,nColumn,cAttribute) ---> Item Index Example: aList = ["one","two","three","four","five"] see find(aList,"three") # print 3 Example: mylist = [["one",1], ["two",2], ["three",3]] see find(mylist,"two",1) + nl # print 2 see find(mylist,2,2) + nl # print 2 Also we can use the binarysearch() function to search in sorted list. Syntax: BinarySearch(List,ItemValue) ---> Item Index BinarySearch(List,ItemValue,nColumn) ---> Search in nColumn, returns the Item Index Example: aList = ["one","two","three","four","five"] aList = sort(aList) see binarysearch(aList,"three") Output: five four one three two 4 21.6. Set List Item 91
- 3. Ring Documentation, Release 1.2 21.8 Sort We can sort the list using the sort() function. Syntax: Sort(List) ---> Sorted List Sort(List,nColumn) ---> Sorted List based on nColumn Sort(List,nColumn,cAttribute) ---> Sorted List based on Object Attribute Example: aList = [10,12,3,5,31,15] aList = sort(aList) see aList # print 3 5 10 12 15 31 We can sort list of strings Example: mylist = ["mahmoud","samir","ahmed","ibrahim","mohammed"] see mylist # print list before sorting mylist = sort(mylist) # sort list see "list after sort"+nl see mylist # print ahmed ibrahim mahmoud mohammed samir We can sort a list based on a specific column. Example: aList = [ ["mahmoud",15000] , ["ahmed", 14000 ] , ["samir", 16000 ] , ["mohammed", 12000 ] , ["ibrahim",11000 ] ] aList2 = sort(aList,1) see aList2 Output: ahmed 14000 ibrahim 11000 mahmoud 15000 mohammed 12000 samir 16000 21.9 Reverse We can reverse a list using the reverse() function. Syntax: 21.8. Sort 92
- 4. Ring Documentation, Release 1.2 Reverse(List) ---> Reversed List Example: aList = [10,20,30,40,50] aList = reverse(aList) see aList # print 50 40 30 20 10 21.10 Insert Items To insert an item in the list we can use the insert() function. Syntax: Insert(List,Index,Item) The inserted item will be AFTER the Index Example: aList = ["A","B","D","E"] insert(aList,2,"C") # Inserts AFTER Index 2, "C" into Position 3 see aList # print A B C D E 21.11 Nested Lists The list may contain other lists Example: aList = [ 1 , [10,20,30] , 5 , [100,1000,5000] ] aList2 = [ "one","two", [3,4], [20,30], ["three", "four", "five",[100,200,300] ] ] see aList[2] # print 10 20 30 see aList[4][3] + nl # print 5000 see aList2[5][2] + nl # print four see aList2[5][4][3] # print 300 21.12 Copy Lists We can copy lists (including nested lists) using the Assignment operator. Example: 21.10. Insert Items 93
- 5. Ring Documentation, Release 1.2 aList = [ "one","two", [3,4], [20,30], ["three", "four", "five",[100,200,300] ] ] aList2 = aList # Copy aList to aList2 aList2[5] = "other" # modify item number five see aList2[5] + nl # print other see aList[5] # print three four five 100 200 300 21.13 First-class lists Lists are first-class citizens where we can store lists in variables, pass lists to functions, and return lists from functions. Example: aList = duplicate( [1,2,3,4,5] ) see aList[10] + nl # print 5 see mylist() # print 10 20 30 40 50 func duplicate list nMax = len(list) for x = 1 to nMax list + list[x] next return list func mylist return [10,20,30,40,50] 21.14 Using Lists during definition We can use the list items while we are defining the list for the first time. Example: aList = [ [1,2,3,4,5] , aList[1] , aList[1] ] see aList # print 1 2 3 4 5 1 2 3 4 5 1 2 3 4 5 21.15 Passing Lists to Functions Lists are passed to functions by reference, This means that the called function will work on the same list and can modify it. Example: func main aList = [1,2,3,4,5] # create list, local in function main 21.13. First-class lists 94
- 6. Ring Documentation, Release 1.2 myfunc(aList) # call function, pass list by reference see aList # print 1 2 3 4 5 6 7 8 9 10 func myfunc list list + [6,7,8,9,10] 21.16 Access List Items by String Index Instead of using numbers to determine the item index when we get item value or set item value, We can access items using string index if the item is a list contains two items and the first item is a string. Example: aList = [ ["one",1] , ["two",2] , ["three",3] ] see aList["one"] + nl + aList["two"] + nl + aList["three"] # print 1 2 3 This type of lists can be defined in a better syntax using the : and = operators. Example: aList = [ :one = 1 , :two = 2 , :three = 3 ] see aList["one"] + nl + aList["two"] + nl + aList["three"] + nl # print 1 2 3 see aList[1] # print one 1 Tip: using : before identifier (one word) means literal Note: using = inside list definition create a list of two items where the first item is the left side and the second item is the right side. We can add new items to the list using the string index Example: aList = [] aList["Egypt"] = "Cairo" aList["KSA"] = "Riyadh" see aList["Egypt"] + nl + # print Cairo aList["KSA"] + nl # print Riyadh 21.17 Passing Parameters Using List This type of lists is very good for passing parameters to functions Where the order of parameters will not be important (we can change the order). Also some parameters maybe optional. Example: 21.16. Access List Items by String Index 95
- 7. Ring Documentation, Release 1.2 myconnect ( [ :server = "myserver.com" , :port = 80 , :username = "mahmoud" , :password = "password" ] ) func myconnect mypara # print connection details see "User Name : " + mypara[:username] + nl + "Password : " + mypara[:password] + nl + "Server : " + mypara[:server] + nl + "Port : " + mypara[:port] 21.17. Passing Parameters Using List 96
- 8. CHAPTER TWENTYTWO STRINGS In this chapter we are going to learn about strings creation and manipulation. 22.1 String Literals Syntax: cStr = "This is a string" cStr2 = 'Another string' cStr3 = :JustAnotherString cStr4 = `Yet "another" 'string' ! ` 22.2 Get String Length We can get the string length (letters count inside a string) using the len() function Syntax: len(string) ---> string length Example: cStr = "How are you?" see cStr + nl see "String size : " + len(cStr) + nl 22.3 Convert Letters Case Syntax: lower(string) ---> convert string letters to lower case upper(string) ---> convert string letters to UPPER case Example: cStr = "Welcome To The Ring Programming Language" see cStr + nl + upper(cStr) + nl + lower(cStr) 97
- 9. Ring Documentation, Release 1.2 22.4 Access String Letters We can access a letter inside a string by the letter index Syntax: string[index] ---> get string letter string[index] = letter # set string letter Example: # print user name letter by letter (each letter in new line) See "Hello, Enter your name : " give cName for x = 1 to len(cName) see nl + cName[x] next We can use for in to get string letters. Example: # print user name letter by letter (each letter in new line) See "Hello, Enter your name : " give cName for x in cName see nl + x next We can modify the string letters Example: # convert the first letter to UPPER case See "Enter your name : " give cName cName[1] = upper(cName[1]) see "Hello " + cName 22.5 Left() Function We can get a specified number of characters from a string using the Left() function. The starting position is 1. Syntax: Left(string,count) Example: see left("Hello World!",5) # print Hello 22.6 Right() Function We can get a specified number of characters from a string using the Right() function. 22.4. Access String Letters 98
- 10. Ring Documentation, Release 1.2 The starting position is the last character on the right. Syntax: Right(string,count) Example: see Right("Hello World!",6) # print World! 22.7 Trim() Function We can remove all leading and trailing spaces from a string using the Trim() function. Syntax: trim(string) Example: cMsg = " Welcome " see trim(cMsg) # print Welcome 22.8 Copy() Function We can duplicate a string more than one time using the copy() function. Syntax: copy(string,nCount) ---> string replicated nCount times Example see copy("***hello***",3) # print ***hello******hello******hello*** 22.9 Lines() Function We can count the number of lines inside a string using the Lines() function. Syntax: lines(string) ---> Number of lines inside the string Example: cStr = "Hello How are you? are you fine?" see lines(cStr) # print 3 22.7. Trim() Function 99