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learn-python3/notebooks/beginner/for_loops.ipynb
Jerry Pussinen 46450175dc Initial commit
2018-05-01 13:59:37 +02:00

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{
"cells": [
{
"cell_type": "markdown",
"metadata": {},
"source": [
"# [`for` loops](https://docs.python.org/3/tutorial/controlflow.html#for-statements)"
]
},
{
"cell_type": "markdown",
"metadata": {},
"source": [
"## Looping lists"
]
},
{
"cell_type": "code",
"execution_count": null,
"metadata": {},
"outputs": [],
"source": [
"my_list = [1, 2, 3, 4, 'Python', 'is', 'neat']\n",
"for item in my_list:\n",
" print(item)"
]
},
{
"cell_type": "markdown",
"metadata": {},
"source": [
"### `break`\n",
"Stop the execution of the loop."
]
},
{
"cell_type": "code",
"execution_count": null,
"metadata": {},
"outputs": [],
"source": [
"for item in my_list:\n",
" if item == 'Python':\n",
" break\n",
" print(item)"
]
},
{
"cell_type": "markdown",
"metadata": {},
"source": [
"### `continue`\n",
"Continue to the next item without executing the lines occuring after `continue` inside the loop."
]
},
{
"cell_type": "code",
"execution_count": null,
"metadata": {},
"outputs": [],
"source": [
"for item in my_list:\n",
" if item == 1:\n",
" continue\n",
" print(item)"
]
},
{
"cell_type": "markdown",
"metadata": {},
"source": [
"### `enumerate()`\n",
"In case you need to also know the index:"
]
},
{
"cell_type": "code",
"execution_count": null,
"metadata": {},
"outputs": [],
"source": [
"for idx, val in enumerate(my_list):\n",
" print('idx: {}, value: {}'.format(idx, val))"
]
},
{
"cell_type": "markdown",
"metadata": {},
"source": [
"## Looping dictionaries"
]
},
{
"cell_type": "code",
"execution_count": null,
"metadata": {},
"outputs": [],
"source": [
"my_dict = {'hacker': True, 'age': 72, 'name': 'John Doe'}\n",
"for val in my_dict:\n",
" print(val)"
]
},
{
"cell_type": "code",
"execution_count": null,
"metadata": {},
"outputs": [],
"source": [
"for key, val in my_dict.items():\n",
" print('{}={}'.format(key, val))"
]
},
{
"cell_type": "markdown",
"metadata": {},
"source": [
"## `range()`"
]
},
{
"cell_type": "code",
"execution_count": null,
"metadata": {},
"outputs": [],
"source": [
"for number in range(5):\n",
" print(number)"
]
},
{
"cell_type": "code",
"execution_count": null,
"metadata": {},
"outputs": [],
"source": [
"for number in range(2, 5):\n",
" print(number)"
]
},
{
"cell_type": "code",
"execution_count": null,
"metadata": {},
"outputs": [],
"source": [
"for number in range(0, 10, 2): # last one is step\n",
" print(number)"
]
}
],
"metadata": {
"kernelspec": {
"display_name": "Python 3",
"language": "python",
"name": "python3"
},
"language_info": {
"codemirror_mode": {
"name": "ipython",
"version": 3
},
"file_extension": ".py",
"mimetype": "text/x-python",
"name": "python",
"nbconvert_exporter": "python",
"pygments_lexer": "ipython3",
"version": "3.5.4"
}
},
"nbformat": 4,
"nbformat_minor": 2
}