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Detailed explanation of add function
The add() function can "add" elements to a collection.
grammar
set.add( element )
parameter
- element : (required) the element to be added
return value
- None, no return value, the value modifies the original collection.
Example: Adding an element to a collection
set1 = {
1, 2, 3}
set1.add(4)
print(set1)
output:
{
1, 2, 3, 4}
1. The order of elements
add() does not insert an element at the "end" of the collection . Because collections "do not guarantee" the "order" of elements , each time we print, the position of the elements will change.
set1 = {
1, 2, 3}
set1.add('ZhangSan')
set1.add('LiSi')
set1.add('WangWu')
set1.add('QianLiu')
set1.add('SunQi')
print(set1)
output:
{
1, 2, 3, 'ZhangSan', 'QianLiu', 'WangWu', 'LiSi', 'SunQi'}
As can be seen from the output results, the elements are not displayed in the order they were added; try printing multiple times, and you will find that the order is different each time.
It should be noted that the order of elements will not change when printing in a "circular" manner
set1 = {
1, 2, 3}
set1.add('ZhangSan')
set1.add('LiSi')
set1.add('WangWu')
set1.add('QianLiu')
set1.add('SunQi')
i = 0
while i < 10:
print(set1)
i += 1
output:
{
'WangWu', 1, 2, 3, 'SunQi', 'ZhangSan', 'LiSi', 'QianLiu'}
{
'WangWu', 1, 2, 3, 'SunQi', 'ZhangSan', 'LiSi', 'QianLiu'}
{
'WangWu', 1, 2, 3, 'SunQi', 'ZhangSan', 'LiSi', 'QianLiu'}
{
'WangWu', 1, 2, 3, 'SunQi', 'ZhangSan', 'LiSi', 'QianLiu'}
{
'WangWu', 1, 2, 3, 'SunQi', 'ZhangSan', 'LiSi', 'QianLiu'}
{
'WangWu', 1, 2, 3, 'SunQi', 'ZhangSan', 'LiSi', 'QianLiu'}
{
'WangWu', 1, 2, 3, 'SunQi', 'ZhangSan', 'LiSi', 'QianLiu'}
{
'WangWu', 1, 2, 3, 'SunQi', 'ZhangSan', 'LiSi', 'QianLiu'}
{
'WangWu', 1, 2, 3, 'SunQi', 'ZhangSan', 'LiSi', 'QianLiu'}
{
'WangWu', 1, 2, 3, 'SunQi', 'ZhangSan', 'LiSi', 'QianLiu'}
2. Types of elements that can be added
The elements added by add() can be "string" , "tuple" , or "bytes type" , but not list, set, or dictionary types.
set1 = {
1, 2, 3}
set1.add('str')
set1.add((4, 5, 6))
set1.add(b'123')
print(set1)
output:
{
1, 2, 3, (4, 5, 6), 'str', b'123'}
When adding an element type that is not allowed, an error will be reported TypeError: unhashable type: 'list'
3. Add repeated elements
The elements in the collection are not allowed to be "repeated" . If you add an element that "already exists" in the collection , the added operation will not be performed, and of course, no error will be reported.
set1 = {
1, 2, 3}
set1.add(3)
print(set1)
output:
{
1, 2, 3}
4. Only one element can be added at a time
add() only accepts one parameter, which means that only "one element" can be added at a time , otherwise an error will be reported TypeError: add() takes exactly one argument
set1.add(1, 2)
