Package gmisclib :: Module dictops

Module dictops

Operations on dictionaries.

Version: $Revision: 1.9 $

Classes
	BadFileFormatError This indicates a problem when reading in a dictionary via read2c.
	dict_of_lists A dictionary of lists.
	dict_of_sets A dictionary of lists.
	dict_of_accums A dictionary of accumulators.
	dict_of_averages A dictionary of accumulators.
	dict_of_maxes A dictionary of maxima.
	dict_of_X A dictionary of arbitrary things.
	list_of_dicts

Functions

dict

filter(d, l)
Passes through items listed in l.

source code

dict

remove(d, l)
Removes items listed in l.

source code

dict

intersection(*dlist)
Returns: a dictionary containing those key=value pairs that are common to all the dictionaries.

source code

test_intersection()

source code

dict

rev1to1(d)
Reverse a 1-1 mapping so it maps values to keys instead of keys to values.

source code

dict

compose(d2, d1)
Compose two mappings (dictionaries) into one.

source code

tuple(dict(str:str), list(str))

read2c(f)
Read in a dictionary from a two-column file; columns are separated by whitespace.

source code

argmax(d)
For a dictionary of key=value pairs, return the key with the largest value.

source code

add_dol(dict, key, value)
OBSOLETE: replace with class dict_of_lists.

source code

add_doc(dict, key, value)
OBSOLETE: replace with class dict_of_accums.

source code

test()

source code

Variables
	__package__ = `None` hash(x)

Function Details

filter(d, l)

source code

Passes through items listed in l.

Parameters:

l (list) - list of keys to preserve
d (mapping) - dictionary to copy/modify.

Returns: dict

a dictionary where all keys not listed in l are removed; all entries listed in l are copied into the (new) output dictionary.

remove(d, l)

source code

Removes items listed in l.

Parameters:

l (list) - list of keys to remove
d (mapping) - dictionary to copy/modify.

Returns: dict

a dictionary where all keys listed in l are removed; all entries not listed in l are copied into the (new) output dictionary.

intersection(*dlist)

source code

Parameters:

dlist (list(dict)) - dictionaries.

Returns: dict

a dictionary containing those key=value pairs that are common to all the dictionaries.

rev1to1(d)

source code

Reverse a 1-1 mapping so it maps values to keys instead of keys to values.

Parameters:

d (dict)

Returns: dict

M such that if m[k]=v, M[v]=k

Raises:

ValueError - if the mapping is many-to-one.

compose(d2, d1)

source code

Compose two mappings (dictionaries) into one.

Parameters:

d2 - second mapping
d1 - first mapping

Returns: dict

d such that d[k] = d2[d1[k]]

read2c(f)

source code

Read in a dictionary from a two-column file; columns are separated by whitespace. This is not a completely general format, because keys cannot contain whitespace and the values cannot start or end in whitespace.

The format can contain comments at the top; these are lines that begin with a hash mark (#). Empty lines are ignored.

Parameters:

f - an open file

Returns: tuple(dict(str:str), list(str))

a dictionary and a list of comments

Note: You can get into trouble if you have a key that starts with a hash mark (#). If it happens to be the first key, and if there are no comments or if it directly follows a comment, it will be interpreted as a comment. To avoid this possibility, begin your file with a comment line, then a blank line.

argmax(d)

source code

For a dictionary of key=value pairs, return the key with the largest value.

Raises:

ValueError - when the input dictionary is empty.

Note: When there are several equal values, this will return a single, arbitrary choice.

add_dol(dict, key, value)

source code

OBSOLETE: replace with class dict_of_lists. Add an entry to a dictionary of lists. A new list is created if necessary; else the value is appended to an existing list. Obsolete: replace with dict_of_lists.

add_doc(dict, key, value)

source code

OBSOLETE: replace with class dict_of_accums. Add an entry to a dictionary of counters. A new counter is created if necessary; else the value is added to an existing counter. Obsolete: replace with dict_of_accums.