Data structures
collection of elements with defined order
flexible: elements can be added, removed, replaced: d.append('B')
indexed elements, zero-based: d[0]
Tuples
like lists that cannot be changed
ordered (indexed)
constant: elements cannot be changed
Sets
collection of unique elements (duplicated values are removed)
no particular order (no index)
flexible: elements can be added, removed, replaced: d.add('B')
logical operations between sets: d1.union(d2)
loop / test: if 'B' in d:
a set is like a dictionary with no values
like sets, but with the possibility to add data to each element: d['Mike']=('Berlin',1983)
no particular order (no index)
elements are unique (key-words)
flexible: elements and data can be added, removed, replaced
Note...
d={} is an empty dictionary
d={'A'} is a set
d=set() is an empty set
d=() is an empty tuple
d=[] is en empty list
To check the data type use:
type(d)
<type 'list'>
Convert data types
# check type
mylist = ['A', 'B', 'A']
type(mylist)
<type 'list'>
# convert list to set
myset=set(mylist)
set(['A', 'B'])
type(myset)
<type 'set'>
# convert text-string into single element list
s = 'filename.txt'
myFileList = [s]
['filename.txt']
"if" check for data type
"if, else" data type testing
x = ['A', 'B']
if type(x) is list:
print('YES, x is a list')
else:
print('NO, x is not a list')
YES, x is a list