Loop over attribute table of selected layer

Question

Here's a stab at my first practical ArcPy script.

I want to grab a layer by name (rather than by layer order or by file path) in the current MXD, then loop over it's attributes (with a view to modifying them). However I don't know the syntax of connecting the desired layer to the attribute table

Here's what I've got so far:

import arcpy

mxd = arcpy.mapping.MapDocument("CURRENT")
needle = "1km_Grid"
df = arcpy.mapping.ListDataFrames(mxd)[0]
for lyr in arcpy.mapping.ListLayers(mxd, "", df):
    if lyr.name == needle:
    # curObj = this layer # pseudo code!

columns = ["MID", "Shape"]

for row in curObj:
    print ("column 1 is: %s" % (row[0]))

Answer 1

After you get the lyr.name, use the Update Cursor to loop over the attributes and make changes as needed.

if lyr.name == needle:
    with arcpy.da.UpdateCursor(lyr, columns) as cursor:
        for row in cursor:
            print "column 1 is: {}".format(row[0])