27.1.21. Vector table

27.1.21.1. Add autoincremental field

Adds a new integer field to a vector layer, with a sequential value for each feature.

This field can be used as a unique ID for features in the layer. The new attribute is not added to the input layer but a new layer is generated instead.

The initial starting value for the incremental series can be specified. Optionally, the incremental series can be based on grouping fields and a sort order for features can also be specified.

参数

标注	名称	类型	描述
输入图层	INPUT	[vector: any]	The input vector layer.
Field name	FIELD_NAME	[string] Default: 'AUTO'	Name of the field with autoincremental values
Start values at 可选	START	[数字] Default: 0	Choose the initial number of the incremental count
Modulus value 可选	MODULUS	[数字] Default: 0	Specifying an optional modulus value will restart the count to START whenever the field value reaches the modulus value. 0 means no restart.
Group values by 可选	GROUP_FIELDS	[tablefield: any] [list]	Select grouping field(s): instead of a single count run for the whole layer, a separate count is processed for each value returned by the combination of these fields.
Sort expression 可选	SORT_EXPRESSION	[expression]	Use an expression to sort the features in the layer either globally or if set, based on group fields.
Sort ascending	SORT_ASCENDING	[boolean] Default: True	When a sort expression is set, use this option to control the order in which features are assigned values.
Sort nulls first	SORT_NULLS_FIRST	[boolean] Default: False	When a sort expression is set, use this option to set whether Null values are counted first or last.
Incremented	OUTPUT	[same as input] Default: [Create temporary layer]	Specify the output vector layer with the auto increment field. One of: Create Temporary Layer (TEMPORARY_OUTPUT) 保存到文件… Save to Geopackage… Save to Database Table… Append to Layer… 文件编码也可以在此更改。

输出

标注	名称	类型	描述
Incremented	OUTPUT	[same as input]	Vector layer with auto incremental field

Python代码

Algorithm ID: native:addautoincrementalfield

import processing
processing.run("algorithm_id", {parameter_dictionary})

当你在数据处理工具箱某个算法前悬停时，算法 id 将会展现。*参数字*将会提供参数的名称与数值。参考详见`数据处理_控制台`以获取如何从Python控制台中运行数据处理算法。

27.1.21.2. Add field to attributes table

Adds a new field to a vector layer.

The name and characteristics of the attribute are defined as parameters.

The new attribute is not added to the input layer but a new layer is generated instead.

参数

标注	名称	类型	描述
输入图层	INPUT	[vector: any]	The input layer
Field name	FIELD_NAME	[string]	Name of the new field
Field type	FIELD_TYPE	[enumeration] Default: 0	Type of the new field. You can choose between: 0 --- Integer 1 --- Float 2 --- String
Field length	FIELD_LENGTH	[数字] Default: 10	Length of the field
Field precision	FIELD_PRECISION	[数字] Default: 0	Precision of the field. Useful with Float field type.
Added	OUTPUT	[same as input] Default: [Create temporary layer]	Specify the output vector layer. One of: Create Temporary Layer (TEMPORARY_OUTPUT) 保存到文件… Save to Geopackage… Save to Database Table… Append to Layer… 文件编码也可以在此更改。

输出

标注	名称	类型	描述
Added	OUTPUT	[same as input]	Vector layer with new field added

Python代码

Algorithm ID: native:addfieldtoattributestable

import processing
processing.run("algorithm_id", {parameter_dictionary})

当你在数据处理工具箱某个算法前悬停时，算法 id 将会展现。*参数字*将会提供参数的名称与数值。参考详见`数据处理_控制台`以获取如何从Python控制台中运行数据处理算法。

27.1.21.3. Add unique value index field

Takes a vector layer and an attribute and adds a new numeric field.

Values in this field correspond to values in the specified attribute, so features with the same value for the attribute will have the same value in the new numeric field.

This creates a numeric equivalent of the specified attribute, which defines the same classes.

The new attribute is not added to the input layer but a new layer is generated instead.

参数

标注	名称	类型	描述
输入图层	INPUT	[vector: any]	The input layer.
Class field	FIELD	[tablefield: any]	Features that have the same value for this field will get the same index.
Output field name	FIELD_NAME	[string] Default: 'NUM_FIELD'	Name of the new field containing the indexes.
Layer with index field	OUTPUT	[vector: any] Default: [Create temporary layer]	Vector layer with the numeric field containing indexes. One of: Skip Output Create Temporary Layer (TEMPORARY_OUTPUT) 保存到文件… Save to Geopackage… Save to Database Table… 文件编码也可以在此更改。
Class summary	SUMMARY_OUTPUT	[table] Default: [Skip output]	Specify the table to contain the summary of the class field mapped to the corresponding unique value. One of: Skip Output Create Temporary Layer (TEMPORARY_OUTPUT) 保存到文件… Save to Geopackage… Save to Database Table… 文件编码也可以在此更改。

输出

标注	名称	类型	描述
Layer with index field	OUTPUT	[same as input]	Vector layer with the numeric field containing indexes.
Class summary	SUMMARY_OUTPUT	[table]	Table with summary of the class field mapped to the corresponding unique value.

Python代码

Algorithm ID: native:adduniquevalueindexfield

import processing
processing.run("algorithm_id", {parameter_dictionary})

当你在数据处理工具箱某个算法前悬停时，算法 id 将会展现。*参数字*将会提供参数的名称与数值。参考详见`数据处理_控制台`以获取如何从Python控制台中运行数据处理算法。

27.1.21.4. Add X/Y fields to layer

Adds X and Y (or latitude/longitude) fields to a point layer. The X/Y fields can be calculated in a different CRS to the layer (e.g. creating latitude/longitude fields for a layer in a projected CRS).

Allows features in-place modification of point features

参数

标注	名称	类型	描述
输入图层	INPUT	[vector: point]	The input layer.
Coordinate system	CRS	[crs] Default: "EPSG:4326"	Coordinate reference system to use for the generated x and y fields.
Field prefix 可选	PREFIX	[string]	Prefix to add to the new field names to avoid name collisions with fields in the input layer.
Added fields	OUTPUT	[vector: point] Default: [Create temporary layer]	Specify the output layer. One of: Create Temporary Layer (TEMPORARY_OUTPUT) 保存到文件… Save to Geopackage… Save to Database Table… Append to Layer… 文件编码也可以在此更改。

输出

标注	名称	类型	描述
Added fields	OUTPUT	[vector: point]	The output layer - identical to the input layer but with two new double fields, x and y.

Python代码

Algorithm ID: native:addxyfieldstolayer

import processing
processing.run("algorithm_id", {parameter_dictionary})

当你在数据处理工具箱某个算法前悬停时，算法 id 将会展现。*参数字*将会提供参数的名称与数值。参考详见`数据处理_控制台`以获取如何从Python控制台中运行数据处理算法。

27.1.21.5. Advanced Python field calculator

Adds a new attribute to a vector layer, with values resulting from applying an expression to each feature.

The expression is defined as a Python function.

参数

标注	名称	类型	描述
输入图层	INPUT	[vector: any]	Input vector layer
Result field name	FIELD_NAME	[string] Default: 'NewField'	Name of the new field
Field type	FIELD_TYPE	[enumeration] Default: 0	Type of the new field. One of: 0 --- Integer 1 --- Float 2 --- String
Field length	FIELD_LENGTH	[数字] Default: 10	Length of the field
Field precision	FIELD_PRECISION	[数字] Default: 3	Precision of the field. Useful with Float field type.
Global expression 可选	GLOBAL	[string]	The code in the global expression section will be executed only once before the calculator starts iterating through all the features of the input layer. Therefore, this is the correct place to import necessary modules or to calculate variables that will be used in subsequent calculations.
Formula	FORMULA	[string]	The Python formula to evaluate. Example: To calculate the area of an input polygon layer you can add: value = $geom.area()
Calculated	OUTPUT	[same as input] Default: [Create temporary layer]	Specify the vector layer with the new calculated field. One of: Create Temporary Layer (TEMPORARY_OUTPUT) 保存到文件… Save to Geopackage… Save to Database Table… 文件编码也可以在此更改。

输出

标注	名称	类型	描述
Calculated	OUTPUT	[same as input]	Vector layer with the new calculated field

Python代码

Algorithm ID: qgis:advancedpythonfieldcalculator

import processing
processing.run("algorithm_id", {parameter_dictionary})

当你在数据处理工具箱某个算法前悬停时，算法 id 将会展现。*参数字*将会提供参数的名称与数值。参考详见`数据处理_控制台`以获取如何从Python控制台中运行数据处理算法。

27.1.21.6. Drop field(s)

Takes a vector layer and generates a new one that has the same features but without the selected columns.

参见

Retain fields

参数

标注	名称	类型	描述
输入图层	INPUT	[vector: any]	Input vector layer to drop field(s) from
Fields to drop	COLUMN	[tablefield: any] [list]	The field(s) to drop
Remaining fields	OUTPUT	[same as input] Default: [Create temporary layer]	Specify the output vector layer with the remaining fields. One of: Create Temporary Layer (TEMPORARY_OUTPUT) 保存到文件… Save to Geopackage… Save to Database Table… Append to Layer… 文件编码也可以在此更改。

输出

标注	名称	类型	描述
Remaining fields	OUTPUT	[same as input]	Vector layer with the remaining fields

Python代码

Algorithm ID: native:deletecolumn

import processing
processing.run("algorithm_id", {parameter_dictionary})

当你在数据处理工具箱某个算法前悬停时，算法 id 将会展现。*参数字*将会提供参数的名称与数值。参考详见`数据处理_控制台`以获取如何从Python控制台中运行数据处理算法。

27.1.21.7. Explode HStore Field

Creates a copy of the input layer and adds a new field for every unique key in the HStore field.

The expected field list is an optional comma separated list. If this list is specified, only these fields are added and the HStore field is updated. By default, all unique keys are added.

The PostgreSQL HStore is a simple key-value store used in PostgreSQL and GDAL (when reading an OSM file with the other_tags field.

参数

标注	名称	类型	描述
输入图层	INPUT	[vector: any]	Input vector layer
HStore field	FIELD	[tablefield: any]	The field(s) to drop
Expected list of fields separated by a comma 可选	EXPECTED_FIELDS	[string] Default: ''	Comma-separated list of fields to extract. The HStore field will be updated by removing these keys.
Exploded	OUTPUT	[same as input] Default: [Create temporary layer]	Specify the output vector layer. One of: Create Temporary Layer (TEMPORARY_OUTPUT) 保存到文件… Save to Geopackage… Save to Database Table… 文件编码也可以在此更改。

输出

标注	名称	类型	描述
Exploded	OUTPUT	[same as input]	Output vector layer

Python代码

Algorithm ID: native:explodehstorefield

import processing
processing.run("algorithm_id", {parameter_dictionary})

当你在数据处理工具箱某个算法前悬停时，算法 id 将会展现。*参数字*将会提供参数的名称与数值。参考详见`数据处理_控制台`以获取如何从Python控制台中运行数据处理算法。

27.1.21.8. Extract binary field

Extracts contents from a binary field, saving them to individual files. Filenames can be generated using values taken from an attribute in the source table or based on a more complex expression.

参数

标注	名称	类型	描述
输入图层	INPUT	[vector: any]	Input vector layer containing the binary data
Binary field	FIELD	[tablefield: any]	Field containing the binary data
File name	FILENAME	[expression]	Field or expression-based text to name each output file
Destination folder	FOLDER	[folder] Default: [Save to temporary folder]	Folder in which to store the output files. One of: Save to a Temporary Directory Save to Directory

输出

标注	名称	类型	描述
Folder	FOLDER	[folder]	The folder that contains the output files.

Python代码

Algorithm ID: native:extractbinary

import processing
processing.run("algorithm_id", {parameter_dictionary})

当你在数据处理工具箱某个算法前悬停时，算法 id 将会展现。*参数字*将会提供参数的名称与数值。参考详见`数据处理_控制台`以获取如何从Python控制台中运行数据处理算法。

27.1.21.9. Field calculator

Opens the field calculator (see 表达式). You can use all the supported expressions and functions.

A new layer is created with the result of the expression.

The field calculator is very useful when used in The model designer.

参数

标注	名称	类型	描述
输入图层	INPUT	[vector: any]	The layer to calculate on
Output field name	FIELD_NAME	[string]	The name of the field for the results
Output field type	FIELD_TYPE	[enumeration] Default: 0	The type of the field. One of: 0 --- Float 1 --- Integer 2 --- String 3 --- Date
Output field width	FIELD_LENGTH	[数字] Default: 10	The length of the result field (minimum 0)
Field precision	FIELD_PRECISION	[数字] Default: 3	The precision of the result field (minimum 0, maximum 15)
Create new field	NEW_FIELD	[boolean] Default: True	Should the result field be a new field
Formula	FORMULA	[expression]	The formula to use to calculate the result
Output file	OUTPUT	[vector: any] Default: [Create temporary layer]	Specification of the output layer. Create Temporary Layer (TEMPORARY_OUTPUT) 保存到文件… Save to Geopackage… Save to Database Table… Append to Layer… 文件编码也可以在此更改。

输出

标注	名称	类型	描述
Calculated	OUTPUT	[vector: any]	Output layer with the calculated field values

Python代码

Algorithm ID: native:fieldcalculator

import processing
processing.run("algorithm_id", {parameter_dictionary})

当你在数据处理工具箱某个算法前悬停时，算法 id 将会展现。*参数字*将会提供参数的名称与数值。参考详见`数据处理_控制台`以获取如何从Python控制台中运行数据处理算法。

27.1.21.10. Refactor fields

Allows editing the structure of the attribute table of a vector layer.

Fields can be modified in their type and name, using a fields mapping.

The original layer is not modified. A new layer is generated, which contains a modified attribute table, according to the provided fields mapping.

备注

When using a template layer with constraints on fields, the information is displayed in the widget with a coloured background and tooltip. Treat this information as a hint during configuration. No constraints will be added on an output layer nor will they be checked or enforced by the algorithm.

The Refactor fields algorithm allows to:

• Change field names and types

• Add and remove fields

• Reorder fields

• Calculate new fields based on expressions

• Load field list from another layer

图 27.125 Refactor fields dialog

参数

标注	名称	类型	描述
输入图层	INPUT	[vector: any]	The layer to modify
Fields mapping	FIELDS_MAPPING	[list]	List of output fields with their definitions. The embedded table lists all the fields of the source layer and allows you to edit them: Click to create a new field. Click to remove a field. Use and to change the selected field order. Click to reset to the default view. For each of the fields you'd like to reuse, you need to fill the following options: Source expression (expression) [expression] Field or expression from the input layer. Field name (name) [string] Name of the field in the output layer. By default input field name is kept. Type (type) [enumeration] Data type of the output field. Available types depend on the output layer provider. Length (length) [number] Length of the output field. Precision (precision) [number] Precision of the output field. Constraints (constraints) [string] When using a template layer, indicates whether there are constraints applied to the template field. Hover over the cell to display the constraints. Load fields from template layer Allows to select a layer from the current project as a template and (with Load fields) fill the above "Fields mapping" options with its fields and their definitions.
Refactored	OUTPUT	[vector: any] Default: [Create temporary layer]	Specification of the output layer. One of: Create Temporary Layer (TEMPORARY_OUTPUT) 保存到文件… Save to Geopackage… Save to Database Table… Append to Layer… 文件编码也可以在此更改。

输出

标注	名称	类型	描述
Refactored	OUTPUT	[vector: any]	Output layer with refactored fields

Python代码

Algorithm ID: native:refactorfields

import processing
processing.run("algorithm_id", {parameter_dictionary})

当你在数据处理工具箱某个算法前悬停时，算法 id 将会展现。*参数字*将会提供参数的名称与数值。参考详见`数据处理_控制台`以获取如何从Python控制台中运行数据处理算法。

27.1.21.11. Rename field

Renames an existing field from a vector layer.

The original layer is not modified. A new layer is generated where the attribute table contains the renamed field.

参见

Refactor fields

参数

标注	名称	类型	描述
输入图层	INPUT	[vector: any]	The input vector layer
Field to rename	FIELD	[tablefield: any]	The field to be altered
New field name	NEW_NAME	[string]	The new field name
Renamed	OUTPUT	[vector: same as input] Default: [Create temporary layer]	Specification of the output layer. One of: Create Temporary Layer (TEMPORARY_OUTPUT) 保存到文件… Save to Geopackage… Save to Database Table… Append to Layer… 文件编码也可以在此更改。

输出

标注	名称	类型	描述
Renamed	OUTPUT	[vector: same as input]	Output layer with the renamed field

Python代码

Algorithm ID: qgis:renametablefield

import processing
processing.run("algorithm_id", {parameter_dictionary})

当你在数据处理工具箱某个算法前悬停时，算法 id 将会展现。*参数字*将会提供参数的名称与数值。参考详见`数据处理_控制台`以获取如何从Python控制台中运行数据处理算法。

27.1.21.12. Retain fields

Takes a vector layer and generates a new one that retains only the selected fields. All other fields will be dropped.

参见

Drop field(s)

参数

标注	名称	类型	描述
输入图层	INPUT	[vector: any]	The input vector layer
Fields to retain	FIELDS	[tablefield: any] [list]	List of fields to keep in the layer
Retained fields	OUTPUT	[vector: same as input] Default: [Create temporary layer]	Specification of the output layer. One of: Create Temporary Layer (TEMPORARY_OUTPUT) 保存到文件… Save to Geopackage… Save to Database Table… Append to Layer… 文件编码也可以在此更改。

输出

标注	名称	类型	描述
Retained fields	OUTPUT	[vector: same as input]	Output layer with the retained fields

Python代码

Algorithm ID: native:retainfields

import processing
processing.run("algorithm_id", {parameter_dictionary})

当你在数据处理工具箱某个算法前悬停时，算法 id 将会展现。*参数字*将会提供参数的名称与数值。参考详见`数据处理_控制台`以获取如何从Python控制台中运行数据处理算法。

27.1.21.13. Text to float

Modifies the type of a given attribute in a vector layer, converting a text attribute containing numeric strings into a numeric attribute (e.g. '1' to 1.0).

The algorithm creates a new vector layer so the source one is not modified.

If the conversion is not possible the selected column will have NULL values.

参数

标注	名称	类型	描述
输入图层	INPUT	[vector: any]	The input vector layer.
Text attribute to convert to float	FIELD	[tablefield: string]	The string field for the input layer that is to be converted to a float field.
Float from text	OUTPUT	[same as input] Default: [Create Temporary Layer]	Specify the output layer. One of: Create Temporary Layer (TEMPORARY_OUTPUT) 保存到文件… Save to Geopackage… Save to Database Table… Append to Layer… 文件编码也可以在此更改。

输出

标注	名称	类型	描述
Float from text	OUTPUT	[same as input]	Output vector layer with the string field converted into a float field

Python代码

Algorithm ID: qgis:texttofloat

import processing
processing.run("algorithm_id", {parameter_dictionary})

当你在数据处理工具箱某个算法前悬停时，算法 id 将会展现。*参数字*将会提供参数的名称与数值。参考详见`数据处理_控制台`以获取如何从Python控制台中运行数据处理算法。