Questions tagged [concatenation]
In formal language theory and computer programming, string concatenation is the operation of joining character strings end-to-end. For example, the concatenation of "snow" and "ball" is "snowball". In some but not all formalisations of concatenation theory, also called string theory, string concatenation is a primitive notion.
63
questions
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Concatenating field names if value is true using QGIS expression
I have multiple boolean fields. I want to create a new string field, that is concatenating the field names of my existing fields when their value is true. I want the names separated by a comma.
I am ...
- 659
0
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0
answers
23
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How to do a location wise pixel correspondence between two different layers?
I have two separate rasters, an RGB orthophoto and a grayscale DEM of the same location. I need to run an object detection algorithm on the RGB orthophoto and then make the bounding box I receive ...
- 139
3
votes
0
answers
66
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QGIS: concats wrong values
I need to create an ID-field in the attribute table for a survey. Since there is more than one person I wanted to create the field in the form "[initials]_[sequence_number]". I have created ...
- 101
1
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0
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62
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Inserting time dimension into 2d array (lon, lat) to create 3d array (time,lat,lon)
I'm trying to create a 3d array with 'time, lat, and lon' dimension. My data is from trmm 3b42 v7. Can someone help me with what should I do. The following are the codes I created.
from netCDF4 import ...
5
votes
2
answers
171
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QGIS: Compare two concatenate fields and add similar strings to new column
I am doing research on how planned improvements in urban green will likely affect biodiversity using QGIS. Each form of urban green has a list of so-called references species, species that are ...
- 59
0
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1
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16
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Concatenation of commands in SAGA grid calc
My goal is to mask pixels with chosen value, for example if g1 is equal to x1,x2,x3 the resulting pixel has to be set to 1 otherwise to 0.
Trough grid calculator I've tried this command:
eq(g1, (x1 or ...
2
votes
2
answers
117
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QGIS: Labelling with parts of an attribute consisting of two or more words
Working in QGIS, I have an attribute consisting of scientific names of species. I would like to label the points on the map with the first 3 left letters of both parts of the binominal scientific name....
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1
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1
answer
62
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Concatenating Attributes from Differing Features (Grouped By Value) Into Single Label
I have been using QGIS 3.28.0 and want to be able to concatenate the attribute values from differing features into the same label with each concatenated value on a separate line. I would group the ...
- 19
1
vote
1
answer
96
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In "Aggregate" tool, concatenate function and \n delimiter doesn't result in break line
I am encountering problems with the 'Aggregate' tool and the 'concatenate' function with the '\n' delimiter. The process is not resulting in a line break as expected.
Please see the screenshot of the ...
- 21
3
votes
2
answers
125
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QGIS expression not working in categorized symbology
In layer properties, when I want to work with categorized symbology, I categorize > value > concatenate(code 1, code 2) and after that, I click on "classify". And QGIS doesn't work (...
4
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1
answer
102
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Combining content of multiple text cells into one field based on common id in QGIS [duplicate]
I need to combine the content of multiple cells into one, this is based on a common "ID". I need this "ID" to remain after the text has been merged. I tried the aggregate tool but ...
- 65
0
votes
1
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205
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Convert Table Column to Comma Separated String
ArcGis Pro 3.0.2
Is there a way to use native tools to convert a column in my Table to a long String where values at separated by a comma? e.g.
my column
1
2
3
Becomes "1,2,3"
I tried using ...
- 305
1
vote
1
answer
140
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Include point coordinates in a string with Google Earth Engine using JavaScript
I am making a time-series plot with data extracted from a point, and I would like to include the point coordinates in the title text.
e.g. 'Timeseries from point (61.08457, 6.03583)'
However, I can't ...
- 147
0
votes
1
answer
31
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Concatenate a month identifier to the end of each year in a list
I am attempting to add a month identifier ('03', '04', etc.) to a list of years in Google Earth Engine.
var year = ee.List.sequence(1992, 2021, 1).map(function(number){return ee.Number(number)})
...
- 13
1
vote
3
answers
61
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How to prevent '+' operator from concatenating rather than summing [closed]
I am trying to sum two fields and am using the expression below.
"Q1 answer" + "Q2 answer"
This expression is concatenating the answer to '32' when the answer should be '5' (3 ...
- 203
1
vote
1
answer
153
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Concatenate attribute data from point, line and polygon layers (QGIS)
I have data from map interviews consisting of three layers (one point layer, one line layer and one polygon layer) within a geopackage. Each layer has the same field structure (as shown below).
The ...
- 109
2
votes
1
answer
151
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Counting substring across multiple fields in QGIS
In QGIS 3.18 I have several fields of concatenated elements (comma-separated), all of which have the possible substring Fort as either one discrete comma-separated element, OR a part of a comma-...
- 1,051
1
vote
1
answer
548
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Expression-based table relation in QGIS, avoiding joins and relates
In QGIS 3.18. I have two tables, one as a part of a .shp and the other a tab-delimited .txt with no geometry:
my .shp attribute table contains a list of sites, and
my .txt table contains a list of ...
- 1,051
2
votes
0
answers
74
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Use aggregate to create a label from multiple shapefiles
I'm trying to fill one field of a line feature shapefile Cables (CAVI) with a default value that updates based on the start coordinate end the end one. The resulting field is a combination of the id ...
- 71
0
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0
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38
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Joining SHP with XLS sheet using Excel
I am trying to join SHP by field CONCATENATE with my XLS sheet.
SHP attributes looks like this:
ID
NAME
CONCATENATE
122
765
122765
345/1
765
345/1765
987/3
345
987/3345
Because of those slashes ...
- 15
6
votes
2
answers
1k
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Concatenate multiple fields where some contain null values (QGIS)
In QGIS 3.18. In a shapefile attribute table, I need to create a field that concatenates several other fields with a comma delimiter. Some of those fields are NULL.
Currently my approach has been ...
- 1,051
4
votes
2
answers
322
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QGIS: concatenate_unique several columns in attributes table
I have a table with points representing villages. Its columns represent the place of the village in different historical periods. Sometimes the names are the same in different columns.
Now, I want to ...
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3
votes
2
answers
161
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Combining columns in attribute table
How can I merge columns in attribute table with / as delimeters?
- 49
4
votes
1
answer
848
views
Concat fields which are not NULL
I am using the concat function in QGIS 3.16.6 on Mac.
I want to join several cell values into one new cell.
With the concat function it is ignoring cells with NULL but it doesn't separate the cell ...
- 41
2
votes
2
answers
301
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Click features & aggregate unique attributes only using QGIS
In QGIS 3.16 the "merge feature attributes" function (on the advanced digitizing toolbar) allows merging the attributes of selected features by either 1) selecting which feature to keep the ...
- 1,051
4
votes
1
answer
418
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'Evaluation error' when using Aggregate tool in QGIS
In QGIS 3.16. I am using the Aggregate function to reduce the number of features in a layer. I am grouping by one field and I want to concatenate the others.
My actual data table is fairly large and ...
- 1,051
4
votes
2
answers
674
views
Area of each polygon that intersects another layer and total area of intersections in QGIS
I have two layers: 'A' (orange) and 'B' (purple).
Using a Virtual Layer and group_concat I am able to list the polygons in layer 'B' that intersect with those in layer 'A'. I found that solution at ...
- 109
4
votes
1
answer
1k
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Merge adjacent polygons & concatenate attribute values (QGIS)
In QGIS 3.16. I have a layer of 1000+ polygons, many of which are adjacent (touching, overlapping, or one completely inside another). If all of the adjacent polygons are merged, I will end up with ...
- 1,051
3
votes
1
answer
378
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adding x and y into single column in QGIS
I have always use the field calculator to retrieve my x and y coords ($x, $y), but this ends up with 2 separate columns, which I then have to manually concatenate.
Is there a way to do this easily ...
- 128
1
vote
1
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401
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How to iterate through various layers and export each with an additional word to its file name
I'm batch dissolving some layers in QGIS and want to save each dissolved shapefile as <layername>_dissolved.shp. I'm using a for-loop but it just shows raise QgsProcessingException(msg) _core....
- 1,219
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0
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97
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QGIS: spatialite incorrect string concatenation when loading layers
I am trying to draw some polygons in spatialite using the DB Manager in QGIS. However
select 1 as id, st_geomfromtext('POLYGON((0 0,0 '||random()||','||random()||' '||random()||','||random()||' 0,0 0))...
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1
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557
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Dropping duplicate strings when using group_concat in Virtual Layer
When using Virtual Layer to group_concat() a string field, the result would contain duplicates string. For example, here's a polygon layer "city_lot" with "land_use" and "...
- 560
2
votes
1
answer
275
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StopIteration: iteration not started
I'm trying to update a given field in this case the last one of the table by concatenating all values in the row excepting null values or '' values.
So far when execute the code until line: print (...
2
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1
answer
970
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Concatenating fields into a new field-QGIS
I'm not sure what I'm missing here. I'm trying to use the field calculator to concatenate multiple fields into one new. All fields are identified as strings.
My expression:
concatenate( "Building" ...
- 21
9
votes
1
answer
13k
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Merging a geodataframe and pandas dataframe based on a column
I have a simple geopandas dataframe that includes geometry and a column called 'MUKEY':
merged_spatial_df.head()
I want to merge it to a tabular (.csv) pandas dataframe (which also has a column ...
- 1,873
3
votes
1
answer
461
views
Get Attributes from 1:n relation in QGIS as Expression to use in Atlas
I need to set up way signs for something like a "hiking-GIS". In the first step I made a network analysis (using QNEAT3) to find the distance from the signs ("Way Signs") to the available destinations ...
- 8,196
4
votes
1
answer
738
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Layout expression for getting all features of layer within the current map view in QGIS 3?
In a map layout template, I want to insert an expression which gets all feature's names of a certain layer, which are contained in the current layout's view/extent. Is there a way to get an aggregate ...
- 1,836
2
votes
1
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2k
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Add column in QGIS
Is it possible to add a column in the attribute table in QGIS that is a concatenation of two other columns? For example I have a column "Genus" and a column "Species" and I would like to create a ...
- 59
4
votes
2
answers
2k
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Concatenate attributes ignoring NULL/missing values with FME
I've got a table with different attributes (named "source:geommetry", "source:name", "source:power"...) I'd like to concatenate to one attribute named "source_all" using FME Desktop. A blank space is ...
- 425
3
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1
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415
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QGIS 2.18 label by expression concatenate field strings
For a building layer I have an attribute table with several fields for the building type where data was entered with a manually created form using checkboxes. Example:
Production: 1 = (yes), 0 = (no)
...
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0
votes
1
answer
115
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Concatenate five fields where some may be NULL
I have a trench containing five types of ducts.
I have created fields the trenches: Type1, Type2, Type3, ...
The values in each field are the numbers of each type of duct that the trench contains.
...
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1
vote
1
answer
348
views
Syntax error when using concat function
I created a field to display the whole route of several photos in a point layer in order to be able to visualize them on the map. I try to do so by using this expression:
concat('C:\Users\DIDAC\...
- 63
3
votes
1
answer
128
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Creating list of intersected polygons for each line using QGIS
I have a line layer representing transport routes.
I would like to add a Virtual Layer listing every city crossed by each line. I would only need the id of each city to be listed (column "...
- 873
1
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0
answers
100
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I want to combine or merge rasters
I am combining many rasters using a "barcode" that describes attributes for each cell. Combine works on integer values: I combine multiple layers using "combine" tool, then create the bar code by ...
- 21
2
votes
1
answer
2k
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Simple Field Calculation With No Results in ArcGIS Pro?
I have a grid in ArcGIS Pro that I've named the X and Y axis (in separate columns) and am now trying to do a field calculation on the total grid name (I've tried using both single and double quotes. I'...
- 3,686
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votes
4
answers
3k
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Concatenating address fields with possible blank or null values in fields using Python parser?
The following Python code is what I have already tried in field calculator of ArcMap 10.5.1:
Pre-Logic Script Code:
def ConcatAddr(!JOIN_KEY!)
val = ""
if !Address! <> val
...
- 125
1
vote
1
answer
109
views
Copying specific folder into subfolders with ArcPy?
I'm working on Arcgis 10.5 and I am trying to achieve this:
On my script, I want to make folders and subfolder, and also I want to copy one specific folder into several subfolders at the same time. ...
1
vote
3
answers
1k
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Concatenating two columns in ArcGIS 10.2.1: "no records within table"?
I am trying to merge two text columns (consisting of 2 digit and 3 digit numbers respectively) into one in ArcGIS 10.2.1 desktop version, but unable to do so. I have added a new field and kept it as ...
- 11
1
vote
1
answer
449
views
Concatenate Label Values Fails to Calculate Aggregate
I'm trying to do what seems like a very simple operation (It's SUPER easy in ArcMap...). I'm kind of a novice with QGIS, so it's probably something really simple that I'm doing incorrectly. The ...
- 129
2
votes
1
answer
2k
views
Concatenating string with space
I am adding a number of strings together to create a linestring but as such I need spaces between the initial XY values and the end XY values, plus a comma in between the two halves.
Should result in ...
- 317