Analysis of commonly used VB functions in the hott

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Analysis of common VB functions in national computer grade examination level 2

y=sgn (x): symbolic function

Description: y=1 when x 0; Y=0 when x=0; When x 0, y=-1

example: ite SGN (5)

output: 1

sin (x), cos (x), Tan (x), ATN (x): trigonometric function

ctype (x): type conversion:

convert x to "Boolean" value

p=cbyte (x)


p=ccur (x)



p=cintl (x)

double precision

p=cdbl (x)


p=clng (x)

long integer

p=csng (x)

single precision

p=cstr (x)


example: ite cdbl (#1/1/1900#)

result: 2

note: true: -1 false: 0

date: #12/30/1899# is 0, and the value is increased by 1 every next day Subtract 1

int (x) from the value of each previous day: take the integer value of =x

fix (x): take the integer part of X and directly remove the decimal part

ite int (-54.6)

the result is: -55 Take the maximum integer of =-54.6

ite int (54.6)

result: 54

ite fix (54.6)

result: 54

ite fix (-54.6)

result: -54

asc (x): returns the character code of the first character of the string

chr (x): returns the character of character code X

p=asc ("a") p=65

p=chr (65) p=a


filter: find a specific string in the string array

p=filter (x, s[, include[, compare]])

parameter x is a string array, and parameter s is the string to be searched. After calling, all x array elements containing string s will be combined to form another string array, and then returned. Filter can also select the array elements without s string after searching. At this time, the parameter three include should be set to false If you search regardless of case, compare is set to vbtextcompare


redimx (2)

x (0) = "kjdfs": X (1) = "wandfkj": X (2) = "fsda"

v=filter (x, "kJ", false)

result: V (0) = "fsda"


instr (x, y) find the position of Y from the first character of x


instr (n, x, y)find the position where y appears from the nth character of X

if y is found in X, the return value is the position where the first character of Y appears

if n string length, X is an empty string, or y cannot be found in X, 0 is returned

if y is an empty string, return n.

instrrev to look for the string upside down

p=instrrev (C, s[, n[, compare]])

look forward from the back of string x, and if found, return the position of s string in the character

n is to search from the first few characters. Set compare to search regardless of case


join (x[, d]) combines the string array into a string They are also very familiar with the security situation of various factories and construction sites

parameter x is a string array. After calling join, all string elements of X will be combined into a string, and then returned


d parameter is used to specify the separator character

x=array ("Da", "fdsa", "FDAs")

p= "Da, fdsa, DSAs"

len (x): calculate the length of string X

the length of the empty character is 0, and the space is also a character. Although the Chinese side occupies 2bytes, it is also a character

14, left (x, n): returns n characters to the left of string X

if n=0, an empty string is returned; if n =len (x), the entire string is returned

15, mid (x, n): read all the following characters from the nth character of X

mid (x, N, m): read M characters from the nth character of X

if n len (x), an empty string is returned. If the nth character is less than M characters, all subsequent characters are returned

16.ltrim (x), rtrim (x), trim (x): remove empty characters

ltrim (x) remove all characters to the left of X

trim (x) remove all characters on the left and right sides of X

rtrim (x) remove all characters on the right side of X

spaces between characters will not be removed

x=ltrim ("this is good")

result: x= "this is good"

x=trim ("this si good")

result: x= "this is good"

ght (x, n): returns n characters to the right of string X

p=replace (x, s, R)

replace the string s in the string x with the string r, and then return

x= "ASP is good"

p=replace (x, good, nice)

p= "ASP is nice"

space (n): return the string composed of N spaces,

p=space (n, x): return the string composed of the first character of N X

x can be a string or a character code

18, split: invade a string into a string array

p=split (s[, d])

take the D parameter as the separating character, and then infringe the string s into multiple strings to form a string array. Then return. If the D parameter is omitted, the space character is used as the separator character

p=split ("a, B, C", "P")

p (0) = "a", P (1) = "B", P (2) = "C"

19, strreverse: reverse the string

pstrreverse (x)

returns the string after X parameter inversion

p=streve's energy consumption and greenhouse gas emissions in the use stage RSE ("ABC")

p= "CBA"

20 ucase (x), lcase (x): convert the case of English letters

p=lcase (x) converts the uppercase letter of string x to lowercase

p=ucase (x) converts the lowercase letter of string x to uppercase

only English letters will be affected

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