Description of valid ID values

Author: nickpowersys

README.md

@@ -75,7 +75,7 @@ Each input file is expected to have (at least) columns representing ID's, time s
 
 To use the automatic column detection functionality, use the keyword argument 'auto' within the pickle_from_file() or dict_from_file() function (see the notebook example or API documentation) and assign it one of the values: 'cycles', 'inside', or 'outside' (for example, auto='inside').
 
-The ID's should contain both letters and digits in some combination (leading zeroes are also allowed in place of letters). Having the string 'id', 'Id' or 'ID' will then cause a column to be the ID index within the combined ID-time stamp index for a given input file. If there is no such label, the leftmost column with alphanumeric strings (for example, 'T12' or '0123') will be taken as the ID.
+The ID's should contain digits, and may also contain letters (leading zeroes are also allowed in place of letters). Having the string 'id', 'Id' or 'ID' will cause a column to be the ID index within the combined ID-time stamp index for a given input file. If there is no such label, the leftmost column with alphanumeric strings (for example, 'T12' or '0123') will be taken as the ID.
 
 Next, CaaR can **create pandas DataFrames**. CaaR and the pandas library offer many functions for summarizing and analyzing the data.
 

README.rst

@@ -74,7 +74,7 @@ Each input file is expected to have (at least) columns representing ID's, time s
 
 To use the automatic column detection functionality, use the keyword argument 'auto' within the pickle_from_file() or dict_from_file() function (see the notebook example or API documentation) and assign it one of the values: 'cycles', 'inside', or 'outside' (for example, auto='inside').
 
-The ID's should contain both letters and digits in some combination (leading zeroes are also allowed in place of letters). Having the string 'id', 'Id' or 'ID' will then cause a column to be the ID index within the combined ID-time stamp index for a given input file. If there is no such label, the leftmost column with alphanumeric strings (for example, 'T12' or '0123') will be taken as the ID.
+The ID's should contain digits, and may also contain letters (leading zeroes are also allowed in place of letters). Having the string 'id', 'Id' or 'ID' will cause a column to be the ID index within the combined ID-time stamp index for a given input file. If there is no such label, the leftmost column with alphanumeric strings (for example, 'T12' or '0123') will be taken as the ID.
 
 Next, CaaR can **create pandas DataFrames**. CaaR and the pandas library offer many functions for summarizing and analyzing the data.