Import csv with python and add headers

Question

Currently I am writing a plugin which allows the user to quickly import a .txt file as a point layer in qgis. The .txt file is output data from a gps device and does not contain a header row. However, I was wondering if it is possible to add headers to the file while importing it as a point layer. Because the .txt structure is always the same, I always know which name a column should have.

Right now I am using addAttributeAlias but this is not satisfying as it only gives an alias to the columns.

Currently I am using the code below for importing the txt file. Is it possible somehow add a line of code in here which allows me add headers for all the columns?

txt_path = self.dlg.lineEdit_txt.text()
txt_info = "?crs=epsg:" + str(crs_rd_new) \
 + "&type=csv&useHeader=No&xField=field_2&yField=field_3&spatialIndex=no&subsetIndex=no&watchFile=no&=&=&=&="
txt_output_filename = os.path.splitext(os.path.basename(txt_path))[0]
txt_vl = QgsVectorLayer("file:///" + txt_path + txt_info, txt_output_filename + ".txt", 'delimitedtext')

• Joseph: What about renaming the columns instead of adding an alias?
• Frank: The .txt files do not contain column headers. When importing them with the current script, they get assigned automatically generated headers ("field_1", "field_2", etc.) The script is used by others and they like to have descriptive headers instead of the generic ones. I sort of solved the problem by adding aliases but I would like to actually name the columns.

Answer 1

When it is imported as a layer in QGIS, you could use the renameAttribute() method to rename your columns.

Example:

txt_path = self.dlg.lineEdit_txt.text()
txt_info = "?crs=epsg:" + str(crs_rd_new) \
 + "&type=csv&useHeader=No&xField=field_2&yField=field_3&spatialIndex=no&subsetIndex=no&watchFile=no&=&=&=&="
txt_output_filename = os.path.splitext(os.path.basename(txt_path))[0]
txt_vl = QgsVectorLayer("file:///" + txt_path + txt_info, txt_output_filename + ".txt", 'delimitedtext')
# To change the name of the first field
txt_vl.startEditing()
txt_vl.renameAttribute(0, 'someName')
txt_vl.updateFields()
txt_vl.commitChanges()