[GIS] the expression for getting a subset of characters in QGIS Field Calculator

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I have a column of 10 character names e.g. L3NAM1988K. How can I delete the first 5 characters and the last 1 character using an expression in the QGis Field Calculator?

Best Answer

Use the substr function under String list for example: substr( 'L3NAM1988K', 6, 4 )

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Related Solutions

[GIS] Removing multiple characters from string field using Field Calculator Python Parser

Even though this question can be considered off topic I though I would make a suggestion.

Try using the Python re module in the Field Calculator. Here is a simple example used in the ArcMap field calculator.

Pre-Logic Script Code

 import re
 def repChar(strg)
     regexChars = '[!@$*#]'
     line = re.sub(regexChars,'',x)
     return line

Field

repChar(strg)

I know this isn't a very detailed excample but it's all I have time for at the moment.

[GIS] Replace non-ASCII characters in QGIS Field Calculator

You can use the \W (upper case W) to match any non-alphanumeric characters.

If using regexp_replace() it seems you need to escape the backslash, so it becomes \\W (thanks, Joseph!)

For example

regexp_replace( '=+&hello%%£world','\\W+','_')

returns

_hello_world

If using the python equivalent function re.sub(), you probably won't need to escape the backslash.

Best Answer

Related Solutions

[GIS] Removing multiple characters from string field using Field Calculator Python Parser

[GIS] Replace non-ASCII characters in QGIS Field Calculator

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