Tabelle- MATLAB & Simulink- MathWorks Italia (2024)

Array in forma tabellare le cui colonne denominate possono essere di tipo diverso

table è un tipo di dati adatto per i dati orientati alle colonne o tabellari, spesso memorizzati come colonne in un file di testo o in un foglio di calcolo. Le tabelle sono costituite da righe e da variabili orientate alle colonne. Ciascuna variabile di una tabella può avere un tipo di dati diverso e una dimensione diversa, con l'unica restrizione che ogni variabile deve avere lo stesso numero di righe. Per maggiori informazioni, vedere Create Tables and Assign Data to Them o guardare Tables and Categorical Arrays (Tabelle e array categorici).

Funzioni

espandi tutto

Creazione di tabelle e conversione del tipo

table	Table array with named variables that can contain different types
array2table	Convert hom*ogeneous array to table
cell2table	Convert cell array to table
struct2table	Convert structure array to table
table2array	Convertire la tabella in array omogeneo
table2cell	Convert table to cell array
table2struct	Convert table to structure array
table2timetable	Convert table to timetable
timetable2table	Convert timetable to table
vartype	Subscript into table or timetable by variable type
convertvars	Convert table or timetable variables to specified data type

Lettura e scrittura di file

Importazione ed esportazione di base

readtable	Create table from file
writetable	Write table to file

Definizione delle regole di importazione

detectImportOptions	Create import options based on file content
spreadsheetImportOptions	Import options object for Spreadsheets
getvaropts	Get variable import options
setvaropts	Set variable import options
setvartype	Set variable data types
preview	Preview eight rows from file using import options

File Parquet

parquetread	Read columnar data from a Parquet file
parquetwrite	Write columnar data to Parquet file
parquetinfo	Get information about Parquet file

Informazioni sintetiche e grafico sovrapposto

summary	Print summary of table, timetable, or categorical array
height	Number of table rows
width	Number of table variables
istable	Determine if input is table
istabular	Determine if input is table or timetable (Da R2021b)
head	Get top rows of array or table
tail	Get bottom rows of array or table
stackedplot	Stacked plot of several variables with common x-axis

Ordinamento, filtro e riorganizzazione

Ordinamento

sortrows	Sort rows of matrix or table
unique	Unique values in array
issortedrows	Determine if matrix or table rows are sorted
topkrows	Top rows in sorted order

Righe del filtro e variabili

rowfilter	Selectively import rows of interest (Da R2022a)
vartype	Subscript into table or timetable by variable type

Riorganizzazione delle variabili

addvars	Add variables to table or timetable
renamevars	Rename variables in table or timetable (Da R2020a)
movevars	Move variables in table or timetable
removevars	Delete variables from table or timetable
splitvars	Split multicolumn variables in table or timetable
mergevars	Combine table or timetable variables into multicolumn variable
convertvars	Convert table or timetable variables to specified data type

Rimodellamento

rows2vars	Reorient table or timetable so that rows become variables
stack	Stack data from input table or timetable into one variable in output table or timetable
unstack	Unstack data from one variable into multiple variables
inner2outer	Invert nested table-in-table hierarchy in tables or timetables

Personalizzazione delle proprietà

addprop	Add custom properties to table or timetable
rmprop	Remove custom properties from table or timetable

Unione e impostazione delle operazioni

Unione tramite variabili chiave

join	Combine two tables or timetables by rows using key variables
innerjoin	Inner join between two tables or timetables
outerjoin	Outer join between two tables or timetables

Impostazione delle operazioni

union	Set union of two arrays
intersect	Set intersection of two arrays
ismember	Array elements that are members of set array
setdiff	Set difference of two arrays
setxor	Set exclusive OR of two arrays

Valori mancanti

anymissing	Determine if any array element is missing (Da R2022a)
ismissing	Find missing values
standardizeMissing	Insert standard missing values
rmmissing	Remove missing entries
fillmissing	Fill missing entries

Applicazione delle funzioni ai contenuti della tabella

pivot	Summarize tabular data in pivoted table (Da R2023a)
groupcounts	Number of group elements
groupfilter	Filter by group (Da R2019b)
groupsummary	Group summary computations
grouptransform	Transform by group
findgroups	Find groups and return group numbers
splitapply	Split data into groups and apply function
rowfun	Apply function to table or timetable rows
varfun	Apply function to table or timetable variables
vartype	Subscript into table or timetable by variable type
convertvars	Convert table or timetable variables to specified data type

App

Data Cleaner

Preprocess and organize column-oriented data (Da R2022a)

Attività di Live Editor

Calcolare per gruppo	Summarize, transform, or filter by group in the Live Editor (Da R2021b)
Tabella Pivot	Summarize tabular data in pivoted table in the Live Editor (Da R2023b)
Unire le tabelle	Combine two tables using key variables in the Live Editor (Da R2019b)
Sovrapporre le variabili della tabella	Combine values from multiple table variables into one table variable in the Live Editor (Da R2020a)
Divergere le variabili della tabella	Distribute values from one table variable to multiple table variables in the Live Editor (Da R2020a)

Argomenti

Create Tables and Assign Data to Them
There are several ways to create tables and assign data to them. You can create tables from input arrays, preallocate tables and fill them in later, or import tables from text files or spreadsheets.
Control How MATLAB Imports Your Data
If you want to control the import process beyond the options provided by the readtable function, such as defining how to handle missing data or errors, then create an import options object before importing the data.
Access Data in Tables
Indexing into tables with parentheses, dot notation, and curly braces accesses table data in different ways. You can use indexing to create a table that is a subset of a larger table or to create an array from data in a table.
- Rename and Describe Table Variables
- Add, Delete, and Rearrange Table Variables
- Add and Delete Table Rows
- Clean Messy and Missing Data in Tables
- Using Row Labels in Table and Timetable Operations
- Convert Text in Table Variables to Categorical
- Add Custom Properties to Tables and Timetables
Direct Calculations on Tables and Timetables
You can perform calculations directly on tables and timetables without indexing to extract their data. All the variables in your tables and timetables must have data types that support calculations.
- Calculations When Tables Have Both Numeric and Nonnumeric Data
- Summarize or Pivot Data in Tables Using Groups
- Perform Calculations by Group in Table
- Rules for Table and Timetable Mathematics
Plots That Support Tables
Create plots by passing tables directly to plotting functions.
Tables of Mixed Data
Use tables to store mixed-type data conveniently, access data with numeric or named indexing, and to store metadata.
Changes to DimensionNames Property in R2016b
Tables can raise compatibility warnings, and changedimension names, when you modify the DimensionNames property.

Esempi in primo piano

Data Cleaning and Calculations in TablesClean data stored in a table or timetable. Perform computations by using the numeric and categorical data that the table contains.

Apri live script

Grouped Calculations in Tables and TimetablesPerform in-place calculations on groups of data in tables and timetables.