{
"cells": [
{
"cell_type": "markdown",
"metadata": {},
"source": [
"## Built-in Functions\n",
"![\"Open](\"https://colab.research.google.com/assets/colab-badge.svg\")
\n",
"\n",
"- named sequence of code that does some specific task or a function\n",
"- we'll learn how to define our own functions in [User Defined Functions chapter](./Ch03-3-Functions-UserDefined.ipynb)\n",
"- some built-in functions we've used so far: type( ), int( ), float( ), str( ), input( ), print( ), etc.\n",
"- Python provides a list of built-in functions that are readily available for use:\n",
"https://docs.python.org/3/library/functions.html\n",
"- below are examples of some built-in functions that may be useful to know"
]
},
{
"cell_type": "markdown",
"metadata": {},
"source": [
"### bin(x)\n",
"- converts an integer number to a binary string prefixed with \"0b\"."
]
},
{
"cell_type": "code",
"execution_count": 1,
"metadata": {},
"outputs": [
{
"data": {
"text/plain": [
"'0b11'"
]
},
"execution_count": 1,
"metadata": {},
"output_type": "execute_result"
}
],
"source": [
"bin(3)"
]
},
{
"cell_type": "markdown",
"metadata": {},
"source": [
"### format(value, format_spec)\n",
"- formats the give value using format spec"
]
},
{
"cell_type": "code",
"execution_count": 1,
"metadata": {},
"outputs": [
{
"name": "stdout",
"output_type": "stream",
"text": [
"Help on built-in function format in module builtins:\n",
"\n",
"format(value, format_spec='', /)\n",
" Return value.__format__(format_spec)\n",
" \n",
" format_spec defaults to the empty string.\n",
" See the Format Specification Mini-Language section of help('FORMATTING') for\n",
" details.\n",
"\n"
]
}
],
"source": [
"help(format)"
]
},
{
"cell_type": "code",
"execution_count": 2,
"metadata": {},
"outputs": [
{
"name": "stdout",
"output_type": "stream",
"text": [
"0b11\n",
"11\n"
]
}
],
"source": [
"# If prefix \"0b is desired or not, use either of the following ways\n",
"print(format(3, '#b'))\n",
"print(format(3, 'b'))"
]
},
{
"cell_type": "markdown",
"metadata": {},
"source": [
"### chr( uniCode )\n",
"- returns the string representing a character whose Unicode code point is the integer uniCode\n",
"- inverse of ord(character)"
]
},
{
"cell_type": "code",
"execution_count": 3,
"metadata": {},
"outputs": [
{
"name": "stdout",
"output_type": "stream",
"text": [
"A\n",
"a\n",
"€\n"
]
}
],
"source": [
"print(chr(65))\n",
"print(chr(97))\n",
"print(chr(8364))"
]
},
{
"cell_type": "markdown",
"metadata": {},
"source": [
"### globals() and locals()\n",
"- globals() returns a dictionary representing the current global symbol table\n",
"- locals() returns a dictionary representing the current local symbol table"
]
},
{
"cell_type": "code",
"execution_count": 4,
"metadata": {},
"outputs": [
{
"data": {
"text/plain": [
"{'__name__': '__main__',\n",
" '__doc__': 'Automatically created module for IPython interactive environment',\n",
" '__package__': None,\n",
" '__loader__': None,\n",
" '__spec__': None,\n",
" '__builtin__': ,\n",
" '__builtins__': ,\n",
" '_ih': ['',\n",
" 'bin(3)',\n",
" '# If prefix \"0b is desired or not, use either of the following ways\\nprint(format(3, \\'#b\\'))\\nprint(format(3, \\'b\\'))',\n",
" 'print(chr(65))\\nprint(chr(97))\\nprint(chr(8364))',\n",
" 'globals()'],\n",
" '_oh': {1: '0b11'},\n",
" '_dh': ['/Volumes/Storage/GoogleDrive/CMU/Python/thinkpythonnotebooks'],\n",
" '_sh': ,\n",
" 'In': ['',\n",
" 'bin(3)',\n",
" '# If prefix \"0b is desired or not, use either of the following ways\\nprint(format(3, \\'#b\\'))\\nprint(format(3, \\'b\\'))',\n",
" 'print(chr(65))\\nprint(chr(97))\\nprint(chr(8364))',\n",
" 'globals()'],\n",
" 'Out': {1: '0b11'},\n",
" 'get_ipython': >,\n",
" 'exit': ,\n",
" 'quit': ,\n",
" '_': '0b11',\n",
" '__': '',\n",
" '___': '',\n",
" '_i': 'print(chr(65))\\nprint(chr(97))\\nprint(chr(8364))',\n",
" '_ii': '# If prefix \"0b is desired or not, use either of the following ways\\nprint(format(3, \\'#b\\'))\\nprint(format(3, \\'b\\'))',\n",
" '_iii': 'bin(3)',\n",
" '_i1': 'bin(3)',\n",
" '_1': '0b11',\n",
" '_i2': '# If prefix \"0b is desired or not, use either of the following ways\\nprint(format(3, \\'#b\\'))\\nprint(format(3, \\'b\\'))',\n",
" '_i3': 'print(chr(65))\\nprint(chr(97))\\nprint(chr(8364))',\n",
" '_i4': 'globals()'}"
]
},
"execution_count": 4,
"metadata": {},
"output_type": "execute_result"
}
],
"source": [
"globals()"
]
},
{
"cell_type": "markdown",
"metadata": {},
"source": [
"### hex(x)\n",
"- convert an integer number to a lowercase hexadecimal string prefixed with \"0x\""
]
},
{
"cell_type": "code",
"execution_count": 5,
"metadata": {},
"outputs": [
{
"name": "stdout",
"output_type": "stream",
"text": [
"0x2a\n",
"-0x2a\n"
]
}
],
"source": [
"print(hex(42))\n",
"print(hex(-42))"
]
},
{
"cell_type": "code",
"execution_count": 2,
"metadata": {},
"outputs": [
{
"name": "stdout",
"output_type": "stream",
"text": [
"0xff\n",
"ff\n",
"FF\n"
]
}
],
"source": [
"# Other ways\n",
"print(format(255, '#x'))\n",
"print(format(255, 'x'))\n",
"print(format(255, 'X'))"
]
},
{
"cell_type": "markdown",
"metadata": {},
"source": [
"### oct(x)\n",
"- return an octal string representation with \"0o\" prefix of a given integer x"
]
},
{
"cell_type": "code",
"execution_count": 7,
"metadata": {},
"outputs": [
{
"name": "stdout",
"output_type": "stream",
"text": [
"0o144\n"
]
}
],
"source": [
"print(oct(100))"
]
},
{
"cell_type": "code",
"execution_count": 8,
"metadata": {},
"outputs": [
{
"name": "stdout",
"output_type": "stream",
"text": [
"0o12\n",
"12\n"
]
}
],
"source": [
"print(format(10, '#o'))\n",
"print(format(10, 'o'))"
]
},
{
"cell_type": "markdown",
"metadata": {},
"source": [
"### ord(c)\n",
"- return an integer representing the Unicode code of a given Unicode character"
]
},
{
"cell_type": "code",
"execution_count": 9,
"metadata": {},
"outputs": [
{
"name": "stdout",
"output_type": "stream",
"text": [
"32\n",
"126\n"
]
}
],
"source": [
"print(ord(' '))\n",
"print(ord('~'))"
]
},
{
"cell_type": "markdown",
"metadata": {},
"source": [
"### id(object)\n",
"- return the 'identity' of an object\n",
"- guaranteed unique integer and constant thoughout its lifetime"
]
},
{
"cell_type": "code",
"execution_count": 10,
"metadata": {},
"outputs": [],
"source": [
"x = 10"
]
},
{
"cell_type": "code",
"execution_count": 11,
"metadata": {},
"outputs": [
{
"data": {
"text/plain": [
"4525196800"
]
},
"execution_count": 11,
"metadata": {},
"output_type": "execute_result"
}
],
"source": [
"id(x)"
]
},
{
"cell_type": "markdown",
"metadata": {},
"source": [
"### divmod(a, b)\n",
"- given two non-complex numbers as arguments, return a pair of numbers as tuple consisting of their quotient and remainder using integer division"
]
},
{
"cell_type": "code",
"execution_count": 12,
"metadata": {},
"outputs": [
{
"name": "stdout",
"output_type": "stream",
"text": [
"(2, 1)\n",
"2 1\n"
]
}
],
"source": [
"print(divmod(7, 3)) # return (quotient, remainder)\n",
"quotient, remainder = divmod(7, 3)\n",
"print(quotient, remainder)"
]
},
{
"cell_type": "markdown",
"metadata": {},
"source": [
"### eval(expression, globals=None, locals=None)\n",
"- the expression argument is parsed and evaluated as Python expression\n",
"- syntax errors reported as exceptions"
]
},
{
"cell_type": "code",
"execution_count": 13,
"metadata": {},
"outputs": [
{
"name": "stdout",
"output_type": "stream",
"text": [
"4\n",
"8\n"
]
}
],
"source": [
"y = 2\n",
"print(eval('y**2'))\n",
"print(eval('y+2*3'))"
]
},
{
"cell_type": "markdown",
"metadata": {},
"source": [
"### max(iterable, ...) or max(arg1, arg2, ...)\n",
"- returns the largest item in an iterable or the largest of two or more arguments"
]
},
{
"cell_type": "code",
"execution_count": 14,
"metadata": {},
"outputs": [
{
"name": "stdout",
"output_type": "stream",
"text": [
"max= 1000.5\n"
]
}
],
"source": [
"print('max=', max(100, 8.9, 999, 1000.5))"
]
},
{
"cell_type": "markdown",
"metadata": {},
"source": [
"### min(arg1, arg2, ...)\n",
"- returns the smallest of the the arguments (arg1, arg2...)"
]
},
{
"cell_type": "code",
"execution_count": 15,
"metadata": {},
"outputs": [
{
"name": "stdout",
"output_type": "stream",
"text": [
"min= 8.9\n"
]
}
],
"source": [
"print('min=', min(100, 8.9, 999, 1000.5))"
]
},
{
"cell_type": "markdown",
"metadata": {},
"source": [
"### pow(base, exponent) \n",
"- returns base to the power exponent"
]
},
{
"cell_type": "code",
"execution_count": 16,
"metadata": {},
"outputs": [
{
"name": "stdout",
"output_type": "stream",
"text": [
"2 to the power 3 = 8\n"
]
}
],
"source": [
"print('2 to the power 3 =', pow(2, 3))"
]
},
{
"cell_type": "markdown",
"metadata": {},
"source": [
"### print()\n",
"- print(*object, sep=' ', end='\\\\n', file=sys.stdout, flush=False)\n",
"- print takes many arguments and print arbitrary number of values\n",
"- demo some print examples with different argument values"
]
},
{
"cell_type": "code",
"execution_count": 17,
"metadata": {},
"outputs": [
{
"name": "stdout",
"output_type": "stream",
"text": [
"hihello"
]
}
],
"source": [
"print('hi', 'hello', sep='', end='')"
]
},
{
"cell_type": "code",
"execution_count": 19,
"metadata": {},
"outputs": [
{
"name": "stdout",
"output_type": "stream",
"text": [
"hi hello"
]
}
],
"source": [
"print('hi', 'hello', sep=' ', end='')"
]
},
{
"cell_type": "code",
"execution_count": 20,
"metadata": {},
"outputs": [
{
"name": "stdout",
"output_type": "stream",
"text": [
"hi hellonext line?\n"
]
}
],
"source": [
"print('hi', 'hello', sep=' ', end='')\n",
"print('next line?')"
]
},
{
"cell_type": "code",
"execution_count": 21,
"metadata": {},
"outputs": [
{
"name": "stdout",
"output_type": "stream",
"text": [
"hi\thello\n",
"next line?\n"
]
}
],
"source": [
"print('hi', 'hello', sep='\\t', end='\\n')\n",
"print('next line?')"
]
},
{
"cell_type": "code",
"execution_count": null,
"metadata": {},
"outputs": [],
"source": []
}
],
"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": "3.7.3"
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"nbformat": 4,
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}