PracticalStuff

Question 1

Help on the len function

Answer 1

len?, len??

Question 2

Create a docstring

Answer 2

Place a string literal in the first line

Question 3

sometimes the ?? suffix doesn’t display any source code

Answer 3

T object in question is not implemented in Python, but in C or ..

Question 4

List every object in the namespace that ends with Warning

Answer 4

*Warning?

Question 5

Find a string method that contains the word find somewhere in its name.

Answer 5

str.find?

Question 6

Make a list of the first 1000 squares, timing it.

Answer 6

%timeit L = [n ** 2 for n in range(1000)]

Question 7

Time steps in a for-loop:

Answer 7

%%timeit
…: L = []
…: for n in range(1000):
…: L.append(n ** 2)

Question 8

Side-by-side subplots:

Answer 8

plt.subplot(221)
p1=plt.hist(ldh_vals.ord_num_value,bins=20,log=False)
plt.subplot(222)
p2=plt.hist(ldh_vals.ord_num_value,bins=20,log=True)
plt.show()

Question 9

List of all magic functions

Answer 9

%lsmagic

Question 10

Help on %timeit

Answer 10

%timeit?

Question 11

List the IPython lines so far:

Answer 11

print(In)

Question 12

List the Cell outputs so far

Answer 12

print(Out)

Question 13

You execute two very expensive computations in cells 2 and 3. You want to the results of 2 and 3.

Answer 13

Out[2] ** 2 + Out[3] ** 2

Question 14

Accessing previous output,

the second-to-last output, to access the third-to-last output

Answer 14

_
__
___

Question 15

Suppress the output of a command is to

Answer 15

add a semicolon to the end
In [14]: math.sin(2) + math.cos(2);
result is computed silently, and the output is neither displayed on the screen or stored in the Out dictionary: