import()

Read(3984) Label: import,

Here’s how to use import() functions.

S.import()

Description:

Retrieve contents from strings as records and return them as a table sequence.

Syntax:

S.import(Fi:type;fmt,…;s)

Note:  

The function retrieves specified or all fields from string S and returns them as a table sequence.

Parameter:

S

A string. Format: separate the records by line break, and the fields by user-defined separator; the default separator is tab

Fi

Fields to be retrieved; by default, all fields will be retrieved

type

Field types include bool, int, long, float, decimal, number, string, date, time and datetime; data type of the first row will be used by default; it is a serial byte key. when the value is an integer; only 16 bytes are allowed in a serial byte value

fmt

Date\time format

s

User-defined separator; the default is tab

Option:  

@t

Take the first row in f as the field name. If not using this option, then use _1, and _2,… as the field name

@c

Use comma as the separator when parameter s is absent

@s

Won’t split strings and data will be imported as a table sequence consisting of strings of single field values; and ignore parameters

@i

Return the result set as a sequence if it only contains one field

@q

Remove the quotation marks, if any, from both ends of each data item, including those in the field names and handle the escape sequences; quotation marks not located at the ends are left alone

@a

Treat single quotes as quotes, including scenarios where the option cooperates with @q option; single quotes are left not handled when both options are absent

@o

 Perform escaping according to the Excel rule, which identifies two double quotation marks as one and does not escape the other characters

@p

Enable handling the matching of parentheses (not including the separators within the parentheses) and quotes, as well as the escape sequences outside of the quotes

@f

Split the file content into a string by the separator without parsing

@l

Allow line continuation and put an escape character \ at the end the line

@k

Retain the whitespaces on both sides of the data item; without it a trim operation will be automatically performed

@e

Generate null if parameter Fi isn’t included in the imported strings; by default, there will be an error report

@d

Delete a record if it contains unmatching data types or data formats and start examining data by type, or if the parentheses and the quotation marks in it do not match when @p option and @q option respectively are present

@n

Ignore a row whose number of columns don’t match the first row

@v

 

In corporation with @d or @n, if a mismatch appears, throw an exception, terminate the execution and output the content of the problem record

@w

Read each row, including the column headers row, as a sequence and return a sequence of sequences

@r

Read contents as a string before parsing so that errors about some character sets can be avoided; the option slows the computation

Return value:  

Table sequence

Example:  

 

A

 

1

=demo.query("select * from EMPLOYEE")

 

2

=A1.(~.array().concat@c())

Convert to the sequence of strings.

 

 

3

=A2(1).import(;",")

Select all fields from a specified string in the sequence. Specify comma as the separator, and return a table sequence as the result.

4

=demo.query("select EID,NAME,SURNAME from EMPLOYEE")

 

5

=A4.export()

6

=A4.export@t(EID:id,NAME:name,SURNAME:surname;"|")

7

=A5.import()

No parameters are given. The default separator will be tab, and _1 and _2,… will be used as field names.

8

=A6.import@t(id:int,name;"|")

Select fields id and name, separated by “|” .

9

=A6.import@f()

With @f option, just split the file as a string using the separator.

 

10

1,2,"3,3",(4,4),[5,5],'6,6'

 

11

=A10.import@c()

With @c option, the default separator is the comma.

12

=A10.import@cp()

With @p option, parentheses and quotation marks matching will be handled during parsing.

13

=A10.import@cpa()

With @a option, single quotation marks are treated as quotation marks.

 

14

=A2(1).import@c()

With @c option, use comma as the default separator.

15

=A5.import@s()

 

With @s option, won’t split strings and records are imported as a single-field table sequence.

16

=A5.import@si()

 

A single-field result set will be returned as a sequence.

17

"uy'd'uj"

 

18

=A17.import()

 

19

=A17.import@q()

 

With @q option, double quotations will be removed before generating the final table sequence With @q option, first remove quotation marks at both ends of each data item (not handling those within) and then convert data into a table sequence.

20

f1,f2,f3

2,"dd""ff",3

 

21

=A20.import@coq()

With @o option, two double quotation marks in one string are treated as one.

 

 

22

=" abc ".import@k()

Retain the whitespaces on boths sides.

23

=A6.import@te(id:int,name,dept;"|")

Generate null since dept doesn’t exist in the imported strings.

24

id|name|surname

a|Rebecca|Moore

2|Ashley|Wilson

3|Rachel|Johnson

4|Emily|Smith

5|Ashley|Smith

6|Matthew|Johnson

7|Alexis|Smith

8|Megan|Wilson

 

25

=A24.import@td(id:int,name;"|")

Delete the record as it contains unmatching data types.

26

=A24.import@tvd(id:int,name;"|")

Check data type matching, and, if error reports, throw an exception, terminate the execution and output the content of the problem record; the error message is: Error in cell A26.

 

27

id|name|surname

1|Rebecca|Moore

2|Ashley

3|Rachel|Johnson

4|Emily

 

28

=A27.import@tdn(id:int,name,surname;"|")

Ignore row 2 and row 3 because the number of columns don’t match that of the table sequence.

29

=A24.import@w(;"|")

Use @w option to read each row as sequecne of sequences.

30

11,22,"3",\

33,44,55,

66,77,88

 

31

=A30.import@l()

With @1 option, allow line continuation when there is an escape character at the end of the line.

Related function:

f.export()

f.import()

A.export()

f. import()

Description:

Read contents from a file and return them as a table sequence.

Syntax:

f.import()

 

f.import(Fi:type:fmt,…;k:n,s)

Retrieve the kth segment of the n segments from the text file. Fi represents the retrieved field; all fields will be retrieved by default. s is the user-defined separator; the default is tab. When retrieving a file segment by segment, it intelligently identifies the ending points to ensure the retrieved records in each segment are complete and all retrieved records are continuous and unique

Note:

The function retrieves file f and returns a table sequence where each record consists of a line of f.

Parameter:

f

A file

Fi

Fields to be retrieved. All fields will be retrieved by default. The sign # is used to represent a field with an ordinal number

type

Field types include bool, int, long, float, decimal, string, date, time and datetime. Data type of the first row will be used by default; when the parameter value is an integer, it represents serial byte key, which allows 16 bytes only

fmt

Date\time format

s

User-defined separator; the default separator is tab. When the parameter is omitted, the comma preceding it can be omitted, too

k

The segment number

n

The number of segments. Retrieve the whole file when both k and n are omitted

Option:

@t

Use the first row of f as the field name. If this option is not used, _1, _2,… will be used as field names; keep the original field names if Fi is #i

@b

Retrieve data from a binary file exported in the export method, with the support for parameter Fi, k and n, and with no support available for parameters type and s. Options @t, @s, @i and @q will be ignored. The segmental retrieval could result in empty segment in cases when a file has only a very small number of records or it is unable to be segmented

@e

Make the function return null when Fi doesn’t exist in the file; raise an error when the option is absent

@s

Do not split the to-be-retrieved field when it is imported as a cursor whose content is a table sequence consisting of strings of a single field; in this case the parameters will be ignored

@i

If the result set has only one column, return it as a sequence

@q

Remove the quotation marks, if any, from both ends of each data item, including those in the field names and handle the escape sequences; quotation marks not located in the ends are left alone

@a

Treat single quotes as quotes, including scenarios where the option cooperates with @q option; single quotes are left not handled when both options are absent

@p

Enable handling the matching of parentheses (not including the separators within the parentheses) and quotes, as well as the escape sequences outside of the quotes

@f

Split the file content into a string by the separator without parsing

@l

Allow line continuation where there is an escape character \ at the end of the line

@m

Use multithreads to increase data retrieval speed, but this will leave an indefinite order for members of the result set. This option will be ignored when parameters k and n exist and it is often used to retrieve data from big files. More than one parallel thread should be specified in configuration information. errors may appear when @o option or parameters k:n are present

@c

Use comma as the separator when the parameter s is absent

@o

Perform escaping according to the Excel rule, which identifies two double quotation marks as one and does not escape the other characters

@k

Retain the whitespaces on both sides of the data item; without it a trim operation will be automatically performed

@d

Delete a record if it contains unmatching data types or data formats and start examining data by type, or if the parentheses and the quotation marks in it do not match when @p option and @q option respectively are present

@n

Ignore and discard rows whose number of columns don’t match the first row

@v

 

Verify data type matching when @d option and @n option are present, and, if error reports, throw an exception, terminate the execution and output the content of the problem record

@w

Read each row, including the column headers row, as a sequence and return a sequence of sequences

@r

Read contents as a string before parsing so that errors about some character sets can be avoided; the option slows the computation

Return value:

Table sequence

Example:

 

A

 

1

=file("D:\\score.txt").import()

2

=file("D:\\score.txt").import@t()

3

=file("D:\\score.txt").import(;1:2)

With Fi and s omitted, get the data of the first of the multiple segments.

4

=file("D:\\Department2.txt").import(;"|")

With Fi, k and n omitted, the whole file is imported.

5

=file("D:\\Department2.txt").import(;1:3,"|")

Omit the fields to be imported.

6

=file("D:\\ EMPLOYEE.txt").import@c(GENDER;1:2)

Retrieve the first segment of GENDER field of comma-seperated EMPLOYEE1.txt.

7

=file("D:\\Department5.txt").import@t(DEPT, MANAGER:int; 1:3,"/")

The contents of Department5.txt are separated with slash and retrieved by the specified fields DEPT and MANAGER.

8

=file("D:\\ score.txt").import@e(EID;1:3)

Return null because there’s no EID field in score.txt.

9

=file("D:\\Department.txt").import@ts()

10

=file("D:\\EMPLOYEE.btx").import@b(;1:2)

Retrieve the first segment of the bin file (a segmented binary file) EMPLOYEE.btx, which is exported from f.export(A,x:F,…).

11

=file("D:\\orders.txt").import@mt(;",")

Increase the speed of retrieving data from the big file. The record order in the result is not the same as that in the file.

12

=file("D:\\StuName.txt").import@i()

StuName.txt has only one column, so return it as a sequence.

13

=file("D:\\test.txt").import@t()

Certain field names and field values are quoted.

14

=file("D:\\test.txt").import@tq()

With @q option, quotation marks at both ends of each data item (including each field name) are removed without handling those within.

15

=file("D:\\Sale1.txt").import()

Get all records from Sale1.txt.

16

=file("D:\\ Sale1.txt").import(#1,#3)

Get the first column and the third column from Sale1.txt.

17

=file("D:/Dep3.txt").import@cqo()

Here is the Dep3.txt file:

With @o option, two double quotation marks are treated as one and return the result as follows:

18

=file("D:/Dep1.txt").import@k()

Retain the whitespaces on both sides of the data item.

19

=file("D:/Department1.txt").import@t(id:int,name;,"|")

20

=file("D:/Department1.txt").import@td(id:int,name;,"|")

Delete the record as it contains unmatching data types.

21

=file("D:/Department1.txt").import@tdv(id:int,name;,"|")

Check data type matching, and, if error reports, throw an exception, terminate the execution and output the content of the problem record.

22

=file("Dep2.txt").import@tdn(id:int,name,surname;,"|")

Here’s the file Dep2.txt:

Ignore and discard row 6 and row 8 because the number of columns don’t match that of the first row.

23

=file("D://EMP1.txt").import@s(;1:2)

Don’t split field values to import as a single-field table; ignore the parameters.

24

=file("D://EMP2.txt").import(#2:date:"yyyy/MM/dd")

EMP2txt:

Parse data in yyyy/MM/dd format as a date type field.

25

=file("City.txt").import@w()

Use @w option to return a sequence of sequences.

26

=file("D://t1.txt").import@c()

Below is file t1.txt:

With @c option, use the comma as the separator by default and return result as follows:

27

=file("D://t1.txt").import@cp()

With @p option, parentheses and quotation marks matching will be handled during parsing.

28

=file("D://t1.txt").import@cpa()

With @a option, single quotation marks are identified as quotation marks.

29

=file("D://t2.txt").import@l()

Below is file t2.txt:

With @1 option, allow line continuation when there is an escape character at the end of the line.

30

=file("D://t3.txt").import@f()

With @f option, just split the file as a string using the separator.

Note:

Text file format: Separate records by carriage return, and fields by the user-defined separator. The default separator is the tab.

Related function:

f.export()

T.import()

Description:

Read in records from an entity table and return them as a table sequence.

Syntax:

T.import(x:C,…;wi,...)

Note:

The function, which is equivalent to T.cursor(...).fetch(), retrieves records from entity table T and returns them as a table sequence.

Parameter:

T

An entity table

x

An expression

C

A column name

wi

Filtering condition; retrieve the whole set when this parameter is absent; separate multiple conditions by comma(s) and their relationships are AND. Besides regular filtering expressions, you can also use the following five types of syntax in a filtering condition, where K is a field in the entity table:

1K=w

w usually uses expression Ti.find(K) or Ti.pfind(K), where Ti is a table sequence. When value of w is null or false, the corresponding record in the entity table will be filtered away; when w is expression Ti.find(K) and the to-be-selected fields C,... contain K, Ti’s referencing field will be assigned to K; when w is expression Ti.pfind(K) and the to-be-selected fields C,... contain K, ordinal numbers of K values in Ti will be assigned to K.

2(K1=w1,Ki=wi,w)

Ki=wi is an assignment expression. Generally, parameter wi can use expression Ti.find(Ki) or Ti.pfind(K), where Ti is a table sequence; when wi is expression Ti.find(Ki) and the to-be-selected fields C,... contain Ki, Ti’s referencing field will be assigned to Ki correspondingly; when wi is expression Ti.pfind(Ki) and the to-be-selected fields C,... contain Ki, ordinal numbers of Ki values in Ti will be assigned to Ki.

w is filter expression; you can reference Ki in w.

3K:Ti

Ti is a table sequence. Compare Ki value in the entity table with key values of Ti and discard records whose Ki value does not match; when the to-be-selected fields C,... contain K, Ti’s referencing field will be assigned to K.

4K:Ti:null

Filter away all records that satisfy K:Ti.

5K:Ti:#

Locate records according to ordinal numbers, compare ordinal numbers of records in table sequence Ti according to the entity table’s K values, and discard non-matching records; when the to-be-selected fields C,... contain K, Ti’s referencing field will be assigned to K

Option:

@v

Enable generating a pure table sequence

@x

Automatically close the entity table after data is fetched from the cursor

Return value:

A table sequence

Example:

 

A

 

1

for 100

 

2

=to(10000).new(#:k1,rand():c1).sort@o(k1)

Generate a set of random data.

3

=to(10000).new(#:k1,rand(10000):c2,rand()*1000:c3).sort@o(k1)

 

4

=A2.cursor()

 

5

=A3.cursor()

 

6

=file("D:\\tb1.ctx")

Create composite table’s base table.

7

=A6.create(#k1,c1)

 

8

=A7.append(A4)

 

9

=A7.attach(table4,c2,c3)

 

10

=A9.append(A5)

 

11

=A9.cursor(;c2<1000;2:3)

Divide records in A9’s attached table where c2 is less than 1000 into 3 segments and return columns in the 2nd segment as a cursor.

12

=A11.fetch()

Fetch data from A11’s cursor.

13

=A9.import@x(;c2<1000;2:3)

Same result as A12; automatically close A9’s entity table after records are retrieved.

Use special types of filtering conditions:

 

A

 

1

=file("emp.ctx")

 

2

=A1.open()

Open the composite table file.

3

=A2.import()

As no parameters are present, return all data in the entity table.

4

=5.new(~:ID,~*~:Num).keys(ID)

Generate a table sequence using ID as the key:

5

=A2.import(EID,NAME;EID=A4.find(EID))

Use filter mode K=w; in this case w is Ti.find(K) and entity table records making EID=A4.find(EID) get null or false are discarded; EID is the selected field, to which table sequence A4’s referencing field is assigned.

6

=A2.import(EID,NAME;EID=A4.pfind(EID))

Use filter mode K=w; in this case w is Ti.pfind(K) and entity table records making EID=A4.pfind(EID) get null or false are discarded; EID is the selected field, to which its ordinal numbers in table sequence A4 are assigned.

7

=A2.import(EID,NAME;EID:A4)

Use filter mode K:Ti; compare the entity table’s EID values with the table sequence’s key values and discard entity table records that cannot match.

8

=A2.import(NAME,SALARY;EID:A4)

This is a case where K isn’t selected; EID isn’t the selected field, so only filtering is performed.

9

=A2.import(EID,NAME;EID:A4:null)

Use filter mode K:Ti:null; compare the entity table’s EID values with the table sequence’s key values and discard entity table records that can match.

10

=A2.import(EID,NAME;EID:A4:#)

Use filter mode K:Ti:#; compare with ordinal numbers of table sequence’s records according to the entity table’s EID values, and discard records that cannot match.

11

=connect("demo").query("select top 2  NAME,GENDER  from employee").keys(NAME)

Return a table sequence using NAME as the key:

12

=A2.import(EID,NAME;(EID=A4.find(EID),NAME=A11.find(NAME),EID!=null&&NAME!=null))

Use filter mode (K1=w1,Ki=wi,w); return records that meet all conditions.

T.import()

Description:

Get a table sequence based on a pseudo table.

Syntax:

T.import(xi:Ci,…)

Note:

The function gets a table sequence based on pseudo table T by specifying field expressions xi and field names Ci, which, by default, field names in the pseudo table. It gets a table sequence using all fields of the pseudo table when parameters xi:Ci are absent.

Parameter:

T

A pseudo table

xi

A field expression

Ci

Field name in the result table sequence

Return value:

A table sequence

Example:

 

A

 

1

=create(file).record(["D:/file/pseudo/empT.ctx"])

 

2

=pseudo(A1)

Generate a pseudo table object.

3

=A2.import()

Get a table sequence from A2’s pseudo table using all its fields since no parameters are present.

4

=A2.import(EID:eid,NAME,SALARY:salary)

Retrieve fields EID, NAME and SALARY from the pseudo table to form a table sequence, and rename fields eid, NAME and salary respectively.