Functions
Contents
Functions¶
Functions can be used to package a set of instructions. These instructions can then be reused for different inputs. Using functions can save you a lot of copying and pasting. Also, if you find a bug in your set of instructions, you only have to fix it once if you use a function instead of copying and pasting.
def fahr_to_celsius(temp_fahr):
''' Convert temperature from degrees F to C '''
temp_celsius = (temp_fahr - 32) * (5/9)
return temp_celsius
help(fahr_to_celsius)
Help on function fahr_to_celsius in module __main__:
fahr_to_celsius(temp_fahr)
Convert temperature from degrees F to C
In IPython (and Jupyter notebooks) there is another way of asking for help by typing the function name with a question mark.
mean?
To use the function:
fahr_to_celsius(32)
0.0
tempF = 212
tempC = fahr_to_celsius(tempF)
print('Temperature in Celsius is:',tempC)
Temperature in Celsius is: 100.0
Multiple outputs¶
def fahr_to_celsius_kelvin(temp_fahr):
''' Convert temperature from degrees F to Celsius and Kelvin '''
temp_celsius = (temp_fahr - 32) * (5/9)
temp_kelvin = temp_celsius + 273
return temp_celsius,temp_kelvin
fahr_to_celsius_kelvin(77)
(25.0, 298.0)
Specifying default values for inputs¶
def fahr_to_celsius_kelvin(temp_fahr=32):
''' Convert temperature from degrees F to Celsius and Kelvin '''
temp_celsius = (temp_fahr - 32) * (5/9)
temp_kelvin = temp_celsius + 273
return temp_celsius,temp_kelvin
fahr_to_celsius_kelvin()
(0.0, 273.0)
Exercises:
Create a function that takes a number as input, and returns the square of that number.
Create a function to calculate the standard deviation of an array (not using the
np.sqrtfunction).