diff options
Diffstat (limited to 'Doc/lib/libshelve.tex')
| -rw-r--r-- | Doc/lib/libshelve.tex | 4 |
1 files changed, 3 insertions, 1 deletions
diff --git a/Doc/lib/libshelve.tex b/Doc/lib/libshelve.tex index 8bd204e331..6ca3576094 100644 --- a/Doc/lib/libshelve.tex +++ b/Doc/lib/libshelve.tex @@ -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 # if no such key) 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: d['xx'] = range(4) # this works as expected, but... d['xx'].append(5) # *this doesn't!* -- d['xx'] is STILL range(4)!!! + # having opened d without writeback=True, you need to code carefully: temp = d['xx'] # extracts the copy temp.append(5) # mutates the copy d['xx'] = temp # stores the copy right back, to persist it + # 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 # consume more memory and make the d.close() operation slower. |