1 | initial version |

How about

```
sage: initial_list = [(3, 2), (4, 2), (4, 3), (5, 2), (5, 3),\
sage: (5, 4), (6, 2), (6, 3), (6, 4), (6, 5), (98,97)]
sage: sublists = []
sage: for product in list(set([a*b for a,b in initial_list])) :
sage: sublists.append([pair for pair in initial_list if pair[0]*pair[1] == product])
```

Or, maybe, as a dictionary:

```
sage: initial_list = [(3, 2), (4, 2), (4, 3), (5, 2), (5, 3),\
sage: (5, 4), (6, 2), (6, 3), (6, 4), (6, 5), (98,97)]
sage: products = list(set([a*b for a,b in initial_list]))
sage: sublists = dict([[product,[]] for product in products])
sage: for pair in initial_list :
sage: product = pair[0]*pair[1]
sage: sublists[product].append(pair)
```

Cheers!

2 | No.2 Revision |

How about

```
sage: initial_list = [(3, 2), (4, 2), (4, 3), (5, 2), (5, 3),\
sage: (5, 4), (6, 2), (6, 3), (6, 4), (6, 5), (98,97)]
sage: sublists = []
sage: for product in list(set([a*b for a,b in initial_list])) :
sage: sublists.append([pair for pair in initial_list if pair[0]*pair[1] == product])
```

Or, maybe, as a dictionary:

```
sage: initial_list = [(3, 2), (4, 2), (4, 3), (5, 2), (5, 3),\
sage: (5, 4), (6, 2), (6, 3), (6, 4), (6, 5), (98,97)]
sage: products = list(set([a*b for a,b in initial_list]))
sage: sublists = dict([[product,[]] for product in products])
sage: for pair in initial_list :
sage: product = pair[0]*pair[1]
sage: sublists[product].append(pair)
```

~~Cheers!~~

Slightly faster method (only multiplying once):

```
sage: initial_list = [(3, 2), (4, 2), (4, 3), (5, 2), (5, 3),\
sage: (5, 4), (6, 2), (6, 3), (6, 4), (6, 5), (98,97)]
sage: sublists = dict()
sage: for pair in initial_list :
sage: product = pair[0]*pair[1]
sage: if not(product in sublists.keys()) :
sage: sublists[product] = []
sage: sublists[product].append(pair)
```

3 | No.3 Revision |

How about

```
sage: initial_list = [(3, 2), (4, 2), (4, 3), (5, 2), (5, 3),\
sage: (5, 4), (6, 2), (6, 3), (6, 4), (6, 5), (98,97)]
sage: sublists = []
sage: for product in list(set([a*b for a,b in initial_list])) :
sage: sublists.append([pair for pair in initial_list if pair[0]*pair[1] == product])
```

Or, maybe, as a dictionary:

```
sage: initial_list = [(3, 2), (4, 2), (4, 3), (5, 2), (5, 3),\
sage: (5, 4), (6, 2), (6, 3), (6, 4), (6, 5), (98,97)]
sage: products = list(set([a*b for a,b in initial_list]))
sage: sublists = dict([[product,[]] for product in products])
sage: for pair in initial_list :
sage: product = pair[0]*pair[1]
sage: sublists[product].append(pair)
```

EDIT:

Slightly faster method (only multiplying once):

```
sage: initial_list = [(3, 2), (4, 2), (4, 3), (5, 2), (5, 3),\
sage: (5, 4), (6, 2), (6, 3), (6, 4), (6, 5), (98,97)]
sage: sublists = dict()
sage: for pair in initial_list :
sage: product = pair[0]*pair[1]
sage: if not(product in sublists.keys()) :
sage: sublists[product] = []
sage: sublists[product].append(pair)
```

EDIT:

Even in a single line :)

```
sage: sublists = dict([[product,[pair for pair in initial_list if pair[0]*pair[1] == product]] for product in list(set([a*b for a,b in initial_list]))])
```

Yeah, I am having fun!

4 | No.4 Revision |

How about

```
sage: initial_list = [(3, 2), (4, 2), (4, 3), (5, 2), (5, 3),\
sage: (5, 4), (6, 2), (6, 3), (6, 4), (6, 5), (98,97)]
sage: sublists = []
sage: for product in list(set([a*b for a,b in initial_list])) :
sage: sublists.append([pair for pair in initial_list if pair[0]*pair[1] == product])
```

Or, maybe, as a ~~dictionary:~~dictionary, with the products as keys:

```
sage: initial_list = [(3, 2), (4, 2), (4, 3), (5, 2), (5, 3),\
sage: (5, 4), (6, 2), (6, 3), (6, 4), (6, 5), (98,97)]
sage: products = list(set([a*b for a,b in initial_list]))
sage: sublists = dict([[product,[]] for product in products])
sage: for pair in initial_list :
sage: product = pair[0]*pair[1]
sage: sublists[product].append(pair)
```

EDIT:

Slightly faster method (only multiplying once):

```
sage: initial_list = [(3, 2), (4, 2), (4, 3), (5, 2), (5, 3),\
sage: (5, 4), (6, 2), (6, 3), (6, 4), (6, 5), (98,97)]
sage: sublists = dict()
sage: for pair in initial_list :
sage: product = pair[0]*pair[1]
sage: if not(product in sublists.keys()) :
sage: sublists[product] = []
sage: sublists[product].append(pair)
```

EDIT:

Even in a single line :)

```
sage: sublists = dict([[product,[pair for pair in initial_list if pair[0]*pair[1] == product]] for product in list(set([a*b for a,b in initial_list]))])
```

Yeah, I am having fun!

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