318 lines
6.8 KiB
Plaintext
318 lines
6.8 KiB
Plaintext
{
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"cells": [
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{
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"cell_type": "markdown",
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"metadata": {},
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"source": [
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"This exercise shows you how to work with variables and expressions, Let's start, press CTRL+ENTER to run the cell.\n",
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"\n",
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"Everytimes there is a `None`, you need to change that to the correct expression.\n",
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"\n",
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"PS: this is exercise `0`, because computers start counting at `0` instead of `1`."
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]
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},
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{
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"cell_type": "code",
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"execution_count": null,
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"metadata": {
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"collapsed": true
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},
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"outputs": [],
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"source": [
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"x = 13\n",
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"print('x: ', x)\n",
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"print('type(x): ', type(x))"
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]
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},
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{
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"cell_type": "markdown",
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"metadata": {},
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"source": [
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"\n",
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"**Excercise:** Apply integer division by `2` on `x` using `//`, replace `None` with the correct expression."
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]
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},
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{
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"cell_type": "code",
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"execution_count": null,
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"metadata": {
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"collapsed": true
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},
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"outputs": [],
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"source": [
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"x = None\n",
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"print('x: ', x)\n",
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"print('type(x): ', type(x))"
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]
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},
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{
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"cell_type": "markdown",
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"metadata": {},
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"source": [
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"Notice that `x` is still an integer\n",
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"\n",
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"**Excercise:** Apply floating point division by `2` on `x` using `/`"
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]
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},
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{
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"cell_type": "code",
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"execution_count": null,
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"metadata": {
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"collapsed": true
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},
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"outputs": [],
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"source": [
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"None\n",
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"print('x: ', x)\n",
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"print('type(x): ', type(x))"
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]
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},
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{
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"cell_type": "markdown",
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"metadata": {},
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"source": [
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"Notice that `x` is a floating point number now, even though `6` is divisible by `2`.\n",
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"\n",
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"**Excercise:** Create a new variable `y`, with value `9`"
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]
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},
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{
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"cell_type": "code",
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"execution_count": null,
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"metadata": {
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"collapsed": true
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},
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"outputs": [],
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"source": [
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"None\n",
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"print('x: ', x, ', y: ', y)\n",
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"print('type(x): ', type(x), ', type(y): ', type(y))"
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]
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},
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{
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"cell_type": "markdown",
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"metadata": {},
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"source": [
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"Notice that x is still a float, and y an integer.\n",
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"\n",
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"**Exercise:** Assign the sum of `x` and `y` to `y`"
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]
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},
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{
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"cell_type": "code",
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"execution_count": null,
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"metadata": {
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"collapsed": true
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},
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"outputs": [],
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"source": [
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"None\n",
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"print('x: ', x, ', y: ', y)\n",
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"print('type(x): ', type(x), ', type(y): ', type(y))"
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]
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},
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{
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"cell_type": "markdown",
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"metadata": {},
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"source": [
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"Notice that `x` did not change, and that y becames a float.\n",
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"\n",
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"**Exercise:** Square `y` using `**`"
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]
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},
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{
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"cell_type": "code",
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"execution_count": null,
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"metadata": {
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"collapsed": true
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},
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"outputs": [],
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"source": [
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"None\n",
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"print('x: ', x, ', y: ', y)\n",
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"print('type(x): ', type(x), ', type(y): ', type(y))"
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]
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},
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{
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"cell_type": "markdown",
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"metadata": {},
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"source": [
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"Now, let's work with strings.\n",
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"\n",
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"**Exercise:** Assign the text value `'https://www.rug.nl/'` to the variable `url`."
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]
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},
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{
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"cell_type": "code",
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"execution_count": null,
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"metadata": {
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"collapsed": true
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},
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"outputs": [],
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"source": [
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"None\n",
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"print('url: ', url, ', type(url): ', type(url))"
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]
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},
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{
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"cell_type": "markdown",
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"metadata": {},
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"source": [
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"**Exercise:** Use `+` and `*` to add `10` asterisks (`'*'`) to the url"
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]
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},
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{
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"cell_type": "code",
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"execution_count": null,
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"metadata": {
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"collapsed": true
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},
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"outputs": [],
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"source": [
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"None\n",
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"print('url: ', url, ', type(url): ', type(url))"
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]
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},
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{
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"cell_type": "markdown",
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"metadata": {},
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"source": [
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"**Exercise:** Use `url.find( ... )` to locate the first asterisk, assign that position to `asterisk_at`"
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]
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},
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{
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"cell_type": "code",
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"execution_count": null,
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"metadata": {
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"collapsed": true
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},
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"outputs": [],
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"source": [
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"None\n",
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"print('url: ', url, ', type(url): ', type(url))\n",
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"print('asterisk_at: ', asterisk_at, ', type(asterisk_at): ', type(asterisk_at))"
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]
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},
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{
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"cell_type": "markdown",
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"metadata": {},
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"source": [
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"**Exercise:** Use `[: ... ]` to extract the first `asterisk_at` characters of `url`, removing the asterisks"
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]
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},
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{
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"cell_type": "code",
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"execution_count": null,
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"metadata": {
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"collapsed": true
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},
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"outputs": [],
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"source": [
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"url = url[: None]\n",
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"print('url: ', url, ', type(url): ', type(url))"
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]
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},
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{
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"cell_type": "markdown",
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"metadata": {},
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"source": [
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"Not everything can be solved by multiplication, addition and such operations, even in mathematics.\n",
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"\n",
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"Even though this is not entirely true, let us assume it is for practical purposes.\n",
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"\n",
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"Some functionality comes as a *function*. One example of such a function is `print`. You use this function with brackets. \n",
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"\n",
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"**Exercise:** get the type of `print` using `type( ... )`."
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]
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},
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{
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"cell_type": "code",
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"execution_count": null,
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"metadata": {
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"collapsed": true
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},
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"outputs": [],
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"source": [
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"type(None)"
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]
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},
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{
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"cell_type": "markdown",
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"metadata": {},
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"source": [
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"The syntax for *calling* functions is similar to that of mathematical functions, like sine and cosine. Python also has those."
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]
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},
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{
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"cell_type": "code",
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"execution_count": null,
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"metadata": {
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"collapsed": true
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},
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"outputs": [],
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"source": [
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"from math import sin, cos, sqrt"
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]
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},
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{
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"cell_type": "markdown",
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"metadata": {},
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"source": [
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"**Exercise:** calculate the sine and cosine of 0, and the square root of 16."
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]
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},
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{
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"cell_type": "code",
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"execution_count": null,
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"metadata": {
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"collapsed": true
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},
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"outputs": [],
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"source": [
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"cosine_at_0 = None\n",
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"sine_at_0 = None\n",
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"sqrt_of_16 = None\n",
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"\n",
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"print('cosine at 0: ', cosine_at_0)\n",
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"print('sine at 0: ', sine_at_0)\n",
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"print('square root of 16: ', sqrt_of_16)"
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]
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},
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{
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"cell_type": "markdown",
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"metadata": {},
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"source": [
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"You've learned about\n",
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"\n",
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" * Expressions: `x * (5 + y)`\n",
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" * Assigments: `x = 5`\n",
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" * Strings: `'Mark ate a burger yesterday'`\n",
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" * Functions: `print('hello')`, `sin( ... )`\n",
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" * Types: `type( ... )`"
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]
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}
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],
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"metadata": {
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"hide_input": false,
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"kernelspec": {
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"display_name": "Python 3",
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"language": "python",
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"name": "python3"
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},
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"language_info": {
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"codemirror_mode": {
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"name": "ipython",
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"version": 3
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},
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"file_extension": ".py",
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"mimetype": "text/x-python",
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"name": "python",
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"nbconvert_exporter": "python",
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"pygments_lexer": "ipython3",
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"version": "3.4.3"
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}
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},
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"nbformat": 4,
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"nbformat_minor": 2
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}
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