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Code Issues Releases Wiki Activity

Don't overwrite built-in name; add some blank lines for readability

This commit is contained in:
Andrew M. Kuchling 2006-07-28 12:45:55 +00:00
parent bd468103e0
commit 1d69a7013f
1 changed files with 3 additions and 1 deletions
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Doc/lib/libshelve.tex
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@ -143,15 +143,17 @@ data = d[key] # retrieve a COPY of data at key (raise KeyError if no
del d[key] # delete data stored at key (raises KeyError del d[key] # delete data stored at key (raises KeyError
# if no such key) # if no such key)
flag = d.has_key(key) # true if the key exists flag = d.has_key(key) # true if the key exists
list = d.keys() # a list of all existing keys (slow!) klist = d.keys() # a list of all existing keys (slow!)
# as d was opened WITHOUT writeback=True, beware: # as d was opened WITHOUT writeback=True, beware:
d['xx'] = range(4) # this works as expected, but... d['xx'] = range(4) # this works as expected, but...
d['xx'].append(5) # *this doesn't!* -- d['xx'] is STILL range(4)!!! d['xx'].append(5) # *this doesn't!* -- d['xx'] is STILL range(4)!!!
# having opened d without writeback=True, you need to code carefully: # having opened d without writeback=True, you need to code carefully:
temp = d['xx'] # extracts the copy temp = d['xx'] # extracts the copy
temp.append(5) # mutates the copy temp.append(5) # mutates the copy
d['xx'] = temp # stores the copy right back, to persist it d['xx'] = temp # stores the copy right back, to persist it
# or, d=shelve.open(filename,writeback=True) would let you just code # or, d=shelve.open(filename,writeback=True) would let you just code
# d['xx'].append(5) and have it work as expected, BUT it would also # d['xx'].append(5) and have it work as expected, BUT it would also
# consume more memory and make the d.close() operation slower. # consume more memory and make the d.close() operation slower.