# Check Data Type and Conversion¶

In this chapter we are going to learn about the functions that can be used for

• Checking Data Type

• Checking Character

• Conversion

## Check Data Type¶

The next functions can be used to check the data type

• isstring()

• isnumber()

• islist()

• type()

• isnull()

## IsString() Function¶

Using the IsString() function we can know if the value is a string or not

Syntax:

```IsString(value) ---> 1 if the value is a string or 0 if not
```

Example:

```see isstring(5) + nl +          # print 0
isstring("hello") + nl      # print 1
```

## IsNumber() Function¶

Using the IsNumber() function we can know if the value is a number or not

Syntax:

```IsNumber(value) ---> 1 if the value is a number or 0 if not
```

Example:

```see isnumber(5) + nl +          # print 1
isnumber("hello") + nl      # print 0
```

## IsList() Function¶

Using the IsList() function we can know if the value is a list or not

Syntax:

```IsList(value) ---> 1 if the value is a list or 0 if not
```

Example:

```see islist(5) + nl +            # print 0
islist("hello") + nl +      # print 0
islist([1,3,5])             # print 1
```

## Type() Function¶

We can know the type of a value using the Type() Function.

Syntax:

```Type(value) ---> The Type as String
```

Example:

```see Type(5) + nl +          # print NUMBER
Type("hello") + nl +        # print STRING
Type([1,3,5])               # print LIST
```

## IsNULL() Function¶

We can check the value to know if it’s null or not using the IsNULL() function

Syntax:

```IsNULL(value) ---> 1 if the value is NULL or 0 if not
```

Example:

```see isnull(5) + nl +        # print 0
isnull("hello") + nl +      # print 0
isnull([1,3,5]) + nl +      # print 0
isnull("") + nl +           # print 1
isnull("NULL")              # print 1
```

## Check Character¶

The next functions can be used to check character

• isalnum()

• isalpha()

• iscntrl()

• isdigit()

• isgraph()

• islower()

• isprint()

• ispunct()

• isspace()

• isupper()

• isxdigit()

## IsAlNum() Function¶

We can test a character or a string using the IsAlNum() Function

Syntax:

```IsAlNum(value) ---> 1 if the value is digit/letter or 0 if not
```

Example:

```see isalnum("Hello") + nl +     # print 1
isalnum("123456") + nl +    # print 1
isalnum("ABCabc123") + nl + # print 1
isalnum("How are you")      # print 0 because of spaces
```

## IsAlpha() Function¶

We can test a character or a string using the IsAlpha() Function

Syntax:

```IsAlpha(value) ---> 1 if the value is a letter or 0 if not
```

Example:

```see isalpha("Hello") + nl +     # print 1
isalpha("123456") + nl +    # print 0
isalpha("ABCabc123") + nl + # print 0
isalpha("How are you")      # print 0
```

## IsCntrl() Function¶

We can test a character or a string using the IsCntrl() Function

Syntax:

```IsCntrl(value) ---> 1 if the value is a control character (no printing position)
or 0 if not
```

Example:

```See iscntrl("hello") + nl +     # print 0
iscntrl(nl)                 # print 1
```

## IsDigit() Function¶

We can test a character or a string using the IsDigit() Function

Syntax:

```IsDigit(value) ---> 1 if the value is a digit or 0 if not
```

Example:

```see isdigit("0123456789") + nl +        # print 1
isdigit("0123a")                    # print 0
```

## IsGraph() Function¶

We can test a character or a string using the IsGraph() Function

Syntax:

```IsGraph(value) ---> 1 if the value can be printed (Except space) or 0 if not
```

Example:

```see isgraph("abcdef") + nl +    # print 1
isgraph("abc def")          # print 0
```

## IsLower() Function¶

We can test a character or a string using the IsLower() Function

Syntax:

```IsLower(value) ---> 1 if the value is lowercase letter or 0 if not
```

Example:

```see islower("abcDEF") + nl +    # print 0
islower("ghi")              # print 1
```

## IsPrint() Function¶

We can test a character or a string using the IsPrint() Function

Syntax:

```IsPrint(value) ---> 1 if the value occupies a printing position or 0 if not
```

Example:

```see isprint("Hello") + nl +             # print 1
isprint("Nice to see you") + nl +   # print 1
isprint(nl)                         # print 0
```

## IsPunct() Function¶

We can test a character or a string using the IsPunct() Function

Syntax:

```IsPunct(value) ---> 1 if the value is a punctuation character or 0 if not
```

Example:

```see ispunct("hello") + nl +     # print 0
ispunct(",")                # print 1
```

## IsSpace() Function¶

We can test a character or a string using the IsSpace() Function

Syntax:

```IsSpace(value) ---> 1 if the value is a white-space or 0 if not
```

Example:

```see isspace("   ") + nl +       # print 1
isspace("test")             # print 0
```

## IsUpper() Function¶

We can test a character or a string using the IsUpper() Function

Syntax:

```IsUpper(value) ---> 1 if the value is an uppercase alphabetic letter or 0 if not
```

Example:

```see isupper("welcome") + nl +    # print 0
isupper("WELCOME")           # print 1
```

## IsXdigit() Function¶

We can test a character or a string using the IsXdigit() Function

Syntax:

```IsXdigit(value) ---> 1 if the value is a hexadecimal digit character or 0 if not
```

Example:

```see isxdigit("0123456789abcdef") + nl +  # print 1
isxdigit("123z")                     # print 0
```

## Conversion¶

The next functions can be used for conversion

• number()

• string()

• ascii()

• char()

• hex()

• dec()

• str2hex()

• hex2str()

## Number() Function¶

We can convert strings to numbers using the Number() function or the + operator.

Syntax:

```Number(string) ---> Number
0 + string ---> Number
```

Example:

```see number("5") + 5 + nl        # print 10
see 0 + "10" + 2                # print 12
```

## String() Function¶

We can convert numbers to strings using the String() function or the + operator.

Syntax:

```String(number) ---> String
"" + number ---> String
```

Example:

```see string(5) + 5 + nl          # print 55
see "" + 10 + 2                 # print 102
```

## Ascii() Function¶

We can get the ASCII code for a letter using the Ascii() function

Syntax:

```Ascii(character) ---> ASCII Code
```

Example:

```See ascii("m") + nl +   # print 109
ascii("M")          # print 77
```

## Char() Function¶

We can convert the ASCII code to character using the Char() function.

Syntax:

```Char(ASCII Code) ---> character
```

Example:

```See char(109) + nl +    # print m
char(77)            # print M
```

## Hex() Function¶

We can convert decimal to hexadecimal using the Hex() function.

Syntax:

```Hex(decimal) ---> hexadecimal
```

Example:

```See hex(10) + nl +      # print a
hex(200)            # print c8
```

## Dec() Function¶

We can convert hexadecimal to decimal using the Dec() function

Syntax:

```Dec(hexadecimal) ---> decimal
```

Example:

```See dec("a") + nl +     # print 10
dec("c8")           # print 200
```

## Str2hex() Function¶

We can convert string characters to hexadecimal characters using the Str2hex() function.

Syntax:

```Str2hex(string) ---> hexadecimal string
```

Example:

```See str2hex("hello")    # print 68656c6c6f
```

## Hex2str() Function¶

We can convert hexadecimal characters to string using the Hex2str() function

Syntax:

```Hex2Str(Hexadecimal string) ---> string
```

Example:

```See hex2str("68656c6c6f")       # print hello
```