Python | Replace elements in second list with index of same element in first list

Given two lists of strings, where first list contains all elements of second list, the task is to replace every element in second list with index of elements in first list.

Method #1: Using Iteration

 `# Python code to replace every element  ` `# in second list with index of first element. ` ` `  `# List Initialization ` `Input1 ``=` `[``'cut'``, ``'god'``, ``'pass'``]  ` `Input2 ``=` `[``'god'``, ``'cut'``, ``'cut'``, ``'cut'``,  ` `          ``'god'``, ``'pass'``, ``'cut'``, ``'pass'``] ` ` `  `# List Initialization ` `Output ``=` `[] ` ` `  `# Using iteration ` `for` `x ``in` `Input2: ` `    ``for` `y ``in` `Input1: ` `        ``if` `x ``=``=` `y: ` `            ``Output.append(Input1.index(y)) ` ` `  `# Printing output ` `print``(``"initial 2 list are"``) ` `print``(Input1, ``"\n"``, Input2) ` `print``(``"Second list after replacement is:"``, Output) `

Output:

```initial 2 list are
['cut', 'god', 'pass']
['god', 'cut', 'cut', 'cut', 'god', 'pass', 'cut', 'pass']
Second list after replacement is: [1, 0, 0, 0, 1, 2, 0, 2]
```

Method #2: Using List comprehension

 `# Python code to replace every element  ` `# in second list with index of first element. ` ` `  `# List initialization ` `Input1 ``=` `[``'cut'``, ``'god'``, ``'pass'``] ` ` `  `# using enumeate ` `temp ``=` `{y:x ``for` `x, y ``in` `enumerate``(Input1)} ` ` `  `# List initialization ` `Input2 ``=` `[``'god'``, ``'cut'``, ``'cut'``, ``'cut'``,  ` `          ``'god'``, ``'pass'``, ``'cut'``, ``'pass'``] ` ` `  `# Using list comprehension ` `Output ``=` `[temp.get(elem) ``for` `elem ``in` `Input2] ` ` `  `# Printing output ` `print``(``"initial 2 list are"``) ` `print``(Input1, ``"\n"``, Input2) ` `print``(``"Second list after replacement is:"``, Output) `

Output:

```initial 2 list are
['cut', 'god', 'pass']
['god', 'cut', 'cut', 'cut', 'god', 'pass', 'cut', 'pass']
Second list after replacement is: [1, 0, 0, 0, 1, 2, 0, 2]
```

Method #3 : Using map

 `# Python code to replace every element  ` `# in second list with index of first element. ` ` `  `# List initialization ` `Input1 ``=` `[``'cut'``, ``'god'``, ``'pass'``] ` ` `  `# List initialization ` `Input2 ``=` `[``'god'``, ``'cut'``, ``'cut'``, ``'cut'``, ` `          ``'god'``, ``'pass'``, ``'cut'``, ``'pass'``] ` ` `  `elem ``=` `{k: i ``for` `i, k ``in` `enumerate``(Input1)} ` `Output ``=` `list``(``map``(elem.get, Input2)) ` ` `  `# Printing output ` `print``(``"initial 2 list are"``) ` `print``(Input1, ``"\n"``, Input2) ` `print``(``"Second list after replacement is:"``, Output) `

Output:

```initial 2 list are
['cut', 'god', 'pass']
['god', 'cut', 'cut', 'cut', 'god', 'pass', 'cut', 'pass']
Second list after replacement is: [1, 0, 0, 0, 1, 2, 0, 2]
```

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