basic programming for data analysis

BASIC PROGRAMMING FOR DATA ANALYSIS

Dr. D. Dutta RoyPsychology Research UnitIndian Statistical Institute

203, B.T. RoadKolkata- 700108

2Dr. D. Dutta Roy, Indian Statistical Institute, [email protected]

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CONTENTS

• Introduction:– Definition, Types of Programming languages,

Characteristics of good algorithm, Flowchart, Programming structure , Data analysis

• Data entry: File handling, reading and printing data, Array, Operators, Commands, Data entry, Statements, Adv.functions

• Data computation :Max score, – result reporting

08:47 AM 08:47 AM Dr. D. Dutta Roy, Indian Statistical Institute, [email protected]

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What is BASIC ?

• BASIC is an useful programming languages for data entry, data analysis and reporting the result. In programming, there are three languages: Machine level/low level (High state and low state or 1 and 0) and higher level languages. BASIC is a higher level language. BASIC means “ Beginner’s All Purpose Symbolic Instructions Code. Computer does not understand the higher level language so higher level language is converted to machine language. Between these two languages, assembly level language exists. It involves a set mnemonic codes. BASIC is simple and easy-to-learn language, particularly suitable for the non-specialist users.


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What is Programming ?• Programming is a set of commands or statements given to

the computer in some computer language. These commands will be executed by the computer in a particular sequence. The list of commands given to the computer for solving a problem is called computer program.Any program written in high level language has to be translated into machine language before it is executed by the computer. This can be achieved with the help of translator programs - compilers (translating entire program and executing the program)and interpreters (translating each step and executing it). BASIC programs are normally interpreted not compiled.


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Algorithms

• Algorithm is a step-by-step procedure for solving a given problem. The characteristics of good algorithm are:– They are simple but offer powerful and general solutions– They are well documented to be used and easily

understood by others– They can be modified easily– They give correct solutions– They save computer time and memory space.– They can be used as sub-procedures for other problems.


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Flow chart

• Flow charting is a diagrammatic representation of the problem solving process, in which decision steps are laid out in logical order.


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OperatorsVariablesNumeric Numeric constat, followed by alphabet

A, A12, A%String String of characters or alphanumeric constants

A$, ADD$OperatorsArithmetic +, -, *, /, ^Relational = , <, >, <>, <=, >='

Logical AND, OR, NOT


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Programming Structure

• Array creation • Opening the input,output,append file• Input/read data• Analysis of data as per programming flow• Displaying the output through file or through

display unit as per user requirement• End


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ARRAYArray is used to store a large amount of data temporarily to different variables. There are two types of array: One dimensional array and two dimensional array.Syntax of one dimensional array

Dim <arrayname> (max.data number)Dim Data (10)

Syntax of Two dimensional arrayDim <arrayname> (max.row, max.col.)Dim Data (10,5)


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Opening and Closing FilesInput and Output statement

One can open atleast 15 files at a time .

Open open n$ for input as #1open n$ for output as #2open n$ for append as #3

Close CloseClose # 3

Read Read DataInput Input "name",name$

Input "age ",ageInput #1, name$, age


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BASIC STATEMENT COMMANDS

Transfer statement GOTO 10GOSUB - RETURN

Conditional statement IF-THEN-ELSEON A GOSUB 10,20ON A GOTO 10,20SELECT CASE

Loop Statement FOR - NEXT


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TRANSFER STATEMENT

• GOTO <LINE NO.>• GOSUB <LINE NO.>...RETURN


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Conditional statement(IF-THEN)

• IF-THEN-ELSE– IF condition 1 THEN statement block 1ELSE IF condition 2 THEN statement block 2ELSE statement block nENDIF


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• ON EXPRESSION% GOTO LINE LIST.• ON EXPRESSION% GOSUB LINE LIST.

Conditional statement(ON GOTO)


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Co

Select case <variable name>case is >= 1statement block1case 2 to 4statement block2case 1statement block 3end select

Conditional statement(SELECT)


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Flow of BASIC program

• There are three types of flow in writing the program:– Sequential flow(working instructions

sequentially)– Repetitive flow(doing same job repeatedly)– Conditional repetitive flow(Flow depends upon

satisfaction of condition)


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Data analysis

• There are three phases of data analysis:– Data entry: data coding and feeding to

computer, data tabulation and verification– Data analysis: selection of useful measurement

techniques and writing program– Display of results: Displaying the data

following user’s specification


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DATA ENTRY AND CODING

• CLS• REM This program is for entering the data and coding the variables• OPEN "c:\windows\desktop\test.dat" FOR APPEND AS #1• LOC1 = 1• LOC2 = 2• 10 INPUT "NAME OF STUDENTS ", NAME$• IF NAME$ = "0" THEN GOTO 100• INPUT "AGE ", AGE• INPUT "LOCALITY (TYPE U FOR URBAN AND R FOR RURAL)

", LOC$• INPUT "MATHEMATICS EXAM. SCORE ", MATH• IF LOC$ = "U" THEN WRITE #1, NAME$, AGE, LOC1, MATH• IF LOC$ = "R" THEN WRITE #1, NAME$, AGE, LOC2, MATH• GOTO 10• 100 END


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Advance FunctionsCONVERT ANY FUNCTION TO

CINT I=CINT (X)

FIX Y=FIX(X) TRUNCATING REAL TO INTEGER

CDBL CDBL(A) CONVERTING SINGLE PRECISION

WIDTH WIDTH 40 SETTING NO. OF CHARACTERS IN A

CHDIR CHDIR "A:\TEST" CONTROL GOTO NEW DIRECTORY

MKDIR MKDIR "B:\HARI" MAKING NEW DIRECTORY

KILL KILL "A:\TEST.OUT" KILLING DEFINED FILE

RMDIR RMDIR "A:\HARI" REMOVING HARI DIRECTORY

FILES FILES "A:*.DAT" SHOWING ALL FILES WITH GIVEN

NAME NAME "TEST.BAS" AS "TEST2.BAS" CHANGING EXISTING

SHELL/EXIT SHELL GOING TO DOS

CLEAR CLEAR SETTING ALL NUMERIC


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Matrix Manipulation• A matrix is a rectangular

array of numbers. In matrix algebra, the array is considered to be a single unit rather than collection of individual entries, and is operated upon as a unit. For calculation of two matrices, there should be the same number of rows and columns.

• A = 105 63 5 218 80 2 220 76 1 84 102 4

• B = 240 121 1 302 28 0


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Addition of two matrices

REM program to add matrices of two sets of dataDIM a(3, 3), b(3, 3), c(3, 3)n = 3: m = 3FOR i = 1 TO nFOR j = 1 TO mREAD a(i, j)DATA 105,63,5,218,80,2,220,76,1PRINT a(i, j)NEXT jNEXT iPRINT

"========================================="

FOR k = 1 TO n FOR l = 1 TO m READ b(k, l)DATA 84,102,4,240,121,1,302,28,0PRINT b(k, l)NEXT lNEXT k

FOR mr = 1 TO n FOR mc = 1 TO m c(mr, mc) = a(mr, mc) + b(mr, mc) NEXT mc NEXT mrPRINT”+++++++++++++++++++++++++”

FOR g = 1 TO n FOR h = 1 TO m PRINT c(g, h) NEXT h NEXT g

basic programming for data analysis

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