readtable(). ismember() the appropriate column of the table.
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I have a .csv file with a list of numbers, what code can I use to check if an inputted number exists in that file.
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I have a .csv file that contains a list of account numbers. How can i check if an inputted number exists in that file. so for example, I write
AN= 256. What code can I use to check if '256' exists in the .csv file or not.
Answers (1)
Walter Roberson
on 2 Dec 2021
2 Comments
Tariq Hammoudeh
on 2 Dec 2021
im sorry but what goes in the paranthesis, also is there a way to use if. so if AN exists in the csv file
Walter Roberson
on 2 Dec 2021
No, there is no MATLAB function that you can pass in a file name and a value and get back the response Yes the value exists in the file or No it does not exist in the file.
You need to read the data in and test the values once they are in memory.
help readtable
READTABLE Create a table by reading from a file.
Use the READTABLE function to create a table by reading column-oriented
data from a file. READTABLE automatically determines the file format from
its extension as described below.
T = READTABLE(FILENAME) creates a table by reading from a file, where
FILENAME can be one of these:
- For local files, FILENAME can be a full path that contains
a filename and file extension. FILENAME can also be a relative path
to the current folder, or to a folder on the MATLAB path.
For example, to import a file on the MATLAB path:
T = readtable("patients.xls");
- For files from an Internet URL or stored at a remote location,
FILENAME must be a full path using a Uniform Resource Locator
(URL). For example, to import a remote file from Amazon S3,
specify the full URL for the file:
T = readtable("s3://bucketname/path_to_file/my_table.xls");
For more information on accessing remote data, see "Work with
Remote Data" in the documentation.
T = READTABLE(FILENAME,"FileType",FILETYPE) specifies the file type, where
FILETYPE is one of "text", "delimitedtext", "fixedwidth", "spreadsheet",
"xml", "html", or "worddocument".
T = READTABLE(FILENAME,OPTS) creates a table by reading from a file stored
at FILENAME using the supplied ImportOptions OPTS. OPTS specifies variable
names, selected variable names, variable types, and other information regarding
the location of the data.
For example, import a subset of the data in a file:
opts = detectImportOptions("patients.xls");
opts.SelectedVariableNames = ["Systolic","Diastolic"];
T = readtable("patients.xls",opts)
READTABLE reads data from different file types as follows:
Text files (delimited and fixed-width):
The following extensions are supported: .txt, .dat, .csv, .log,
.text, .dlm
Reading from a delimited text file creates one variable in T for each
column in the file. Variable names can be taken from the first row of
the file. By default, the variables created are either double, if the
column is primarily numeric, or datetime, duration, or text etc. If
data in a column cannot be converted to numeric, datetime or
duration, the column is imported as text.
Spreadsheet files:
The following extensions are supported: .xls, .xlsx, .xlsb, .xlsm,
.xltm, .xltx, .ods
Reading from a spreadsheet file creates one variable in T for each
column in the file. By default, the variables created are either
double, datetime or text--depending on the type in the file.
READTABLE converts both empty fields or cells and values which cannot
be converted to the expected type to:
- NaN (for a numeric or duration variable),
- NaT (for a datetime variable),
- Empty character vector ('') or missing string (for text variables).
Word documents:
The following extensions are supported: .docx
Reading from a Word document file imports data from a table. Each column
in the table creates one variable in T. Variable names can be taken from
the first row of the table. By default, the variables created are either
double, if the column is primarily numeric, or datetime, duration, or
text etc. If data in a column cannot be converted to numeric, datetime
or duration, the column is imported as text. The default data type for
text import is string.
HTML files:
The following extensions are supported: .html, .xhtml, .htm
Reading from an HTML file imports data from a <TABLE> element. Each
column in the table creates one variable in T. Variable names can be
taken from the first row of the table. By default, the variables created
are either double, if the column is primarily numeric, or datetime,
duration, or text etc. If data in a column cannot be converted to
numeric, datetime or duration, the column is imported as text. The
default data type for text import is string.
XML files:
The following extensions are supported: .xml
Tabular structure present within an XML file:
<table> ----------------------------- Table Node
<row> --------------------------- Row Node
<date>2019-07-11</date> ----- Variable Node
<index>8191</index>
<name>Lorem</name>
</row>
<row>
<date>2020-01-04</date>
<index>131071</index>
<name>Ipsum</name>
</row>
</table>
Reading from an XML file creates one row in T for each repeated node
in the file that is detected under the table node. Variable names are
taken from the names of the child nodes under the row nodes in the file.
Name-Value Pairs for ALL file types:
------------------------------------
"FileType" - Specify the file as "text", "delimitedtext",
"fixedwidth", "spreadsheet", "xml", "html",
or "worddocument".
"VariableNamingRule" - A character vector or a string scalar that
specifies how the output variables are named.
It can have either of the following values:
'modify' Modify variable names to make them
valid MATLAB Identifiers.
(default)
'preserve' Preserve original variable names
allowing names with spaces and
non-ASCII characters.
"MissingRule" - Rules for interpreting missing or
unavailable data:
"fill" Replace missing data with the
contents of the "FillValue"
property.
"error" Stop importing and display an
error message showing the missing
record and field.
"omitrow" Omit rows that contain missing
data.
"omitvar" Omit variables that contain
missing data.
"ImportErrorRule" - Rules for interpreting nonconvertible
or bad data:
"fill" Replace the data where errors
occur with the contents of the
"FillValue" property.
"error" Stop importing and display an
error message showing the
error-causing record and field.
"omitrow" Omit rows where errors occur.
"omitvar" Omit variables where errors
occur.
"ReadRowNames" - Whether or not to import the first variable
as row names. Defaults to false.
"TreatAsMissing" - Text which is used in a file to represent
missing data, e.g. "NA".
"TextType" - The type to use for text variables, specified
as "char" or "string".
"DatetimeType" - The type to use for date variables, specified
as "datetime", "text", or "exceldatenum".
Defaults to "datetime".
Name-Value Pairs for TEXT and SPREADSHEET only:
-----------------------------------------------
"Range" - The range to consider when detecting data.
Specified using any of the following syntaxes:
- Starting cell: A string or character vector
containing a column letter and a row number,
or a 2 element numeric vector indicating
the starting row and column.
- Rectangular range: A start and end cell separated
by colon, e.g. "C2:N15", or a four element
numeric vector containing start row, start
column, end row, end column, e.g. [2 3 15 13].
- Row range: A string or character vector
containing a starting row number and ending
row number, separated by a colon.
- Column range: A string or character vector
containing a starting column letter and
ending column letter, separated by a colon.
- Starting row number: A numeric scalar
indicating the first row where data is found.
"NumHeaderLines" - The number of header lines in the file.
"ExpectedNumVariables" - The expected number of variables.
"ReadVariableNames" - Whether or not to expect variable names in
the file. Defaults to true.
Name-Value Pairs for TEXT, XML, HTML, and Word documents only:
--------------------------------------------------------------
"DateLocale" - The locale used to interpret month and day
names in datetime text. Must be a character
vector or scalar string in the form xx_YY.
See the documentation for DATETIME for more
information.
"DecimalSeparator" - Character used to separate the integer part
of a number from the decimal part of the
number.
"ThousandsSeparator" - Character used to separate the thousands
place digits.
Name-Value Pairs for TEXT, XML, and HTML only:
----------------------------------------------
"Encoding" - The character encoding scheme associated with
the file.
Name-Value Pairs for TEXT and XML only:
---------------------------------------
"DurationType" - The type to use for duration, specified as
"duration" or "text". Defaults to "duration".
"Whitespace" - Characters to treat as whitespace.
"TrimNonNumeric" - Whether or not to remove nonnumeric characters
from a numeric variable. Defaults to false.
"HexType" - Set the output type of a hexadecimal
variable.
"BinaryType" - Set the output type of a binary variable.
"CollectOutput" - Whether or not to concatenate consecutive output
of the same MATLAB class into a single array.
Defaults to false.
Name-Value Pairs for TEXT, HTML, and Word documents only:
---------------------------------------------------------
"RowNamesColumn" - The column where the row names are
located.
Name-Value Pairs for TEXT only:
-------------------------------
"Delimiter" - Field delimiter characters in a delimited
text file, specified as a character
vector, string scalar, cell array of
character vectors, or string array.
"CommentStyle" - Style of comments, specified as a
character vector, string scalar, cell
array of character vectors, or string
array.
"LineEnding" - End-of-line characters, specified as a
character vector, string scalar, cell
array of character vectors, or string
array.
"ConsecutiveDelimitersRule" - Rule to apply to fields containing
multiple consecutive delimiters:
"split" Split consecutive delimiters
into multiple fields.
"join" Join the delimiters into one
single delimiter.
"error" Ignore consecutive delimiters
during detection (treated as
"split"), but the
resulting read will error.
"LeadingDelimitersRule" - Rule to apply to delimiters at the
beginning of a line:
"keep" Keep leading delimiters.
"ignore" Ignore leading delimiters.
"error" Ignore leading delimiters
during detection, but the
resulting read will error.
"TrailingDelimiterRule" - Rule to apply to delimiters at the
end of a line:
"keep" Keep trailing delimiters.
"ignore" Ignore trailing delimiters.
"error" Ignore trailing delimiters
during detection, but the
resulting read will error.
"VariableWidths" - Widths of the variables for a fixed width
file.
"EmptyLineRule" - Rule to apply to empty lines in the file:
"skip" Skip empty lines.
"read" Read empty lines.
"error" Ignore empty lines during
detection, but the resulting
read will error.
"VariableNamesLine" - The line where the variable names are
located.
"PartialFieldRule" - Rule to handle partial fields in the data:
"keep" Keep the partial field data
and convert the text to the
appropriate data type.
"fill" Replace missing data with the
contents of the "FillValue"
property.
"omitrow" Omit rows that contain
partial data.
"omitvar" Omit variables that contain
partial data.
"wrap" Begin reading the next line
of characters.
"error" Ignore partial field data
during detection, but the
resulting read will error.
"VariableUnitsLine" - The line where the variable units are
located.
"VariableDescriptionsLine" - The line where the variable descriptions
are located.
"ExtraColumnsRule" - Rule to apply to extra columns of data
that appear after the expected variables:
"addvars" Creates new variables to
import extra columns. If there
are N extra columns, then import
new variables as "ExtraVar1",
"ExtraVar2",..., "ExtraVarN".
"ignore" Ignore the extra columns of
data.
"wrap" Wrap the extra columns of
data to new records.
"error" Display an error message and
abort the import operation.
Name-Value Pairs for SPREADSHEET only:
--------------------------------------
"UseExcel" - Whether or not to read the spreadsheet
file using Microsoft(R) Excel(R) on
Windows(R):
true - Opens an instance of Microsoft Excel
to read the file on a Windows system
with Excel installed.
false - Does not open an instance of Microsoft
Excel to read the file. This is the
default setting.
"Sheet" - The sheet from which to read the table.
"DataRange" - Where the table data is located.
"RowNamesRange" - Where the row names are located.
"VariableNamesRange" - Where the variable names are located.
"VariableUnitsRange" - Where the variable units are located.
"VariableDescriptionsRange" - Where the variable descriptions are
located.
Name-Value Pairs for HTML and Word documents only:
--------------------------------------------------
"TableIndex" - Integer selection which table to extract.
"VariableNamesRow" - The row where the variable names are
located.
"VariableUnitsRow" - The row where the variable units are
located.
"VariableDescriptionsRow" - The row where the variable descriptions
are located.
"EmptyRowRule" - Rule to apply to empty lines in the file:
"skip" Skip empty lines.
"read" Read empty lines.
"error" Ignore empty lines during
detection, but the resulting
read will error.
"EmptyColumnRule" - Rule to apply to empty columns in the file:
"skip" Skip empty columns.
"read" Read empty columns.
"error" Error on empty columns.
Name-Value Pairs for HTML, Word documents, and XML only:
--------------------------------------------------------
"TableSelector" - XPath expression that selects the table
to extract.
Name-Value Pairs for XML only:
------------------------------
"RowNodeName" - Node name which delineates rows of
the output table.
"RowSelector" - XPath expression that selects the XML
Element nodes which delineate rows of
the output table.
"VariableNodeNames" - Node names which will be treated as
variables of the output table.
"VariableSelectors" - XPath expressions that select the XML
Element nodes to be treated as variables
of the output table.
"TableNodeName" - Name of the node which contains table
data. If multiple nodes have the same
name, READTABLE uses the first node
with that name.
"VariableUnitsSelector" - XPath expression that selects the XML
Element nodes containing the variable
units.
"VariableDescriptionsSelector" - XPath expression that selects the XML
Element nodes containing the variable
descriptions.
"RowNamesSelector" - XPath expression that selects the XML
Element nodes containing the row names.
"RepeatedNodeRule" - Rule for managing repeated nodes in a
given row of a table:
"addcol" Add a column for each
repeated node.
"ignore" Ignore repeated nodes.
"error" Ignore repeated nodes
during detection, but the
resulting read will error.
"ImportAttributes" - Import XML node attributes as variables
of the output table. Defaults to true.
"AttributeSuffix" - Suffix to append to all output table
variable names corresponding to
attributes in the XML file. Defaults
to "Attribute".
"RegisteredNamespaces" - The namespace prefixes that are mapped
to namespace URLs for use in selector
expressions.
Name-Value Pairs supported with Text and Spreadsheet Import Options OPTS:
-------------------------------------------------------------------------
These have slightly different behavior when used with import options:
T = readtable(FILENAME, OPTS, "Name1", Value1, "Name2", Value2, ...)
"ReadVariableNames" true - Reads the variable names from the
opts.VariableNamesRange or opts.VariableNamesLine
location.
false - Uses variable names from the import options.
"ReadRowNames" true - Reads the row names from the opts.RowNamesRange
or opts.RowNamesColumn location.
false - Does not import row names.
Text parameters:
"DateLocale" - Override the locale used when importing dates.
"Encoding" - Override the encoding defined in import options.
Spreadsheet only parameters:
"Sheet" - Override the sheet value in the import options.
See also READTIMETABLE, READMATRIX, READCELL, WRITETABLE, TABLE,
DETECTIMPORTOPTIONS, TEXTSCAN.
Documentation for readtable
doc readtable
help ismember
ISMEMBER True for set member.
LIA = ISMEMBER(A,B) for arrays A and B returns an array of the same
size as A containing true where the elements of A are in B and false
otherwise.
LIA = ISMEMBER(A,B,'rows') for matrices A and B with the same number
of columns, returns a vector containing true where the rows of A are
also rows of B and false otherwise.
[LIA,LOCB] = ISMEMBER(A,B) also returns an array LOCB containing the
lowest absolute index in B for each element in A which is a member of
B and 0 if there is no such index.
[LIA,LOCB] = ISMEMBER(A,B,'rows') also returns a vector LOCB containing
the lowest absolute index in B for each row in A which is a member
of B and 0 if there is no such index.
The behavior of ISMEMBER has changed. This includes:
- occurrence of indices in LOCB switched from highest to lowest
- tighter restrictions on combinations of classes
If this change in behavior has adversely affected your code, you may
preserve the previous behavior with:
[LIA,LOCB] = ISMEMBER(A,B,'legacy')
[LIA,LOCB] = ISMEMBER(A,B,'rows','legacy')
Examples:
a = [9 9 8 8 7 7 7 6 6 6 5 5 4 4 2 1 1 1]
b = [1 1 1 3 3 3 3 3 4 4 4 4 4 9 9 9]
[lia1,locb1] = ismember(a,b)
% returns
lia1 = [1 1 0 0 0 0 0 0 0 0 0 0 1 1 0 1 1 1]
locb1 = [14 14 0 0 0 0 0 0 0 0 0 0 9 9 0 1 1 1]
[lia,locb] = ismember([1 NaN 2 3],[3 4 NaN 1])
% NaNs compare as not equal, so this returns
lia = [1 0 0 1], locb = [4 0 0 1]
Class support for inputs A and B, where A and B must be of the same
class unless stated otherwise:
- logical, char, all numeric classes (may combine with double arrays)
- cell arrays of strings (may combine with char arrays)
-- 'rows' option is not supported for cell arrays
- objects with methods SORT (SORTROWS for the 'rows' option), EQ and NE
-- including heterogeneous arrays derived from the same root class
See also ISMEMBERTOL, INTERSECT, UNION, UNIQUE, UNIQUETOL, SETDIFF,
SETXOR, SORT, SORTROWS.
Documentation for ismember
doc ismember
Other functions named ismember
categorical/ismember mtree/ismember
cell/ismember nominal/ismember
dataset/ismember sym/ismember
datetime/ismember tabular/ismember
duration/ismember tall/ismember
gpuArray/ismember textanalytics.internal.wordlist/ismember
See Also
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