# Python | Add the occurrence of each number as sublists

Given a list of numbers, the task is to count the occurrence of each element and add as sublists.

Examples:

```Input: l1 = [3, 5, 7, 2, 3, 5, 9.1]
Output: [[3, 2], [5, 2], [7, 1], [2, 1], [9.1, 1]]

Input: l1 = [1, 1, 2, 2, 3, 1]
Output: [[1, 3], [2, 2], [3, 1]]
```

Note: Format output 2d list is [[‘item1’, ‘count1’], [‘item2’, ‘count2’], …, [‘itemN’, ‘countN’]].

Code #1: Using count() method

 `# Python program to add the occurrence ` `# of each number as sublists ` `def` `count_occur(list1, ``*``*``kwargs): ` `     `  `    ``# iterate over list item ` `    ``for` `i ``in` `list1: ` `        ``row ``=``[] ` `        ``ct ``=` `0` `     `  `        ``# count function will count occurrence ` `        ``ct ``=` `list1.count(i) ` `        ``row.append(i) ` `        ``row.append(ct) ` `        ``# append 1d list items to 2d list ` `        ``list2.append(row) ` `     `  `    ``# below code is to eliminate  ` `    ``# repetitive list items ` `    ``for` `j ``in` `list2: ` `        ``if` `j ``not` `in` `unq_l2: ` `            ``unq_l2.append(j) ` `             `  `    ``return` `unq_l2 ` ` `  `# Driver Code ` `l1 ``=` `[``3``, ``5``, ``7``, ``2``, ``3``, ``5``, ``9.1``] ` `list2 ``=` `[] ` `unq_l2 ``=` `[] ` `print``(count_occur(l1)) `

Output:

```[[3, 2], [5, 2], [7, 1], [2, 1], [9.1, 1]]
```

Code #2: Using loop method

 `def` `count_occur(list1): ` ` `  `    ``for` `i ``in` `range``(``0``, ``len``(l1)): ` `        ``a ``=` `0` `        ``row ``=``[] ` `        ``if` `i ``not` `in` `l: ` `            ``for` `j ``in` `range``(``0``, ``len``(l1)): ` ` `  `                ``# matching items from both lists ` `                ``if` `l1[i]``=``=` `l1[j]: ` ` `  `                    ``# on match counter increments by 1 ` `                    ``a ``=` `a ``+` `1` ` `  `            ``row.append(l1[i]) ` `            ``row.append(a) ` ` `  `            ``# append function will append  ` `            ``# 1d list items to 2d list ` `            ``l.append(row) ` `             `  `    ``# below code is to eliminate ` `    ``# repetitive list items     ` `    ``for` `j ``in` `l: ` `        ``if` `j ``not` `in` `unq_l: ` `            ``unq_l.append(j) ` `             `  `    ``return` `unq_l ` ` `  `# Driver code         ` `l1 ``=``[``3``, ``5``, ``7``, ``2``, ``3``, ``5``, ``9.1``] ` `l ``=``[] ` `unq_l ``=``[] ` ` `  `print``(count_occur(l1))  `

Output:

```[[3, 2], [5, 2], [7, 1], [2, 1], [9.1, 1]]
```

Code #3: Using counter() method

 `# Python program to add the occurrence ` `# of each number as sublists using counter() method ` ` `  `from` `collections ``import` `Counter ` `def` `count_occurence(l): ` `    ``c ``=` `Counter(l) ` `    ``l1 ``=` `[] ` `    ``for` `k,v ``in` `c.items(): ` `        ``l1.append([k,v]) ` `    ``return` `l1 ` ` `  ` `  `# Driver code      ` `l ``=` `[``3``, ``5``, ``7``, ``2``, ``3``, ``5``, ``9.1``] ` `print``(count_occurence(l)) `

Output:

```[[2, 1], [3, 2], [9.1, 1], [5, 2], [7, 1]]
```

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