lat, lng to lng, lat in polygon WKT - axis flip

Question

I have a sheet with the column with polygon information in WKT format. However, the data taken are from web mapping (OSM or google maps) and in the order of lat, lng. When I am using the solution from this thread (Visualising WKT geometry string in QGIS) which are what I need, I do not have another choice to switch x and y other than manually. But concerning the number of data, I need to find something more efficient.

Basically my polygon data is in the format

55.947686 -3.132133, 55.945932 -3.131232, 55.947878 -3.121362, 55.943168 -3.117714, 55.943841 -3.108273, 55.94771 -3.108745, 55.950161 -3.119216

but I need -

-3.132133 55.947686, -3.131232 55.945932, ....

There are so many items in the dataset so manual transfer is not an option.

Is there a tool somewhere (even outside QGIS environment) to do it for me?

Screenshot for an answer from BERA:

Answer 1

You can flip them using Python:

import re

layer = iface.activeLayer() #Click layer in table of contents
unflipped_field = 'wktstring' #Change
flipped_field = 'wktflipped' #Change. This text field will be calculated

with edit(layer):
    for f in layer.getFeatures(): #For each row in the attribute table
        oldval = f[unflipped_field] #Fetch unflipped wkt string
        templist = re.findall(r"[-+]?\d*\.\d+|\d+", oldval) #Extract digits from string (https://stackoverflow.com/questions/4703390/how-to-extract-a-floating-number-from-a-string)
        templist = ['{0} {1}'.format(v2,v1) for (v1,v2) in zip(templist[::2], templist[1::2])] #Swap first and second val for all coordinate pairs
        newval = ', '.join(templist) #Join list back to a string
        f[flipped_field] = newval #Update new field
        layer.updateFeature(f)