Note Avant toute chose, veuillez choisir votre langue dans le menu Langs
(attention à ne pas avoir les 2 langues en même temps).
Note First of all, please choose your language from the Langs
menu (be careful not to have both languages at the same time).
The Python programming language can be used interactively to know that when you type a command, Python executes it immediately and displays the answer:
1+1
2
* selected (blue frame) * selected and in edit mode (green frame)
Exercise: modify the calculation cell above to calculate 1 + 2
print(1 + 7*2)
print(49**0.5)
print(7 % 5)
15 7.0 2
The print
command allows to display a result which is different from the result of the cell (which is the result of the last command).
Python has basic operators (including the **
operators for power and %
for the modulo).
For more advanced mathematical functions we must import libraries (we will see later what libraries are). We start with the scientific library NumPy
:
from numpy import *
print(sin(3.14))
print(sin(pi))
print(log(e))
0.0015926529164868282 1.2246467991473532e-16 1.0
log2(16)
4.0
For documentation on a function use ?
(Specific to iPython). In regular Python we do help (log)
. You have to run the cell (Shift + Enter) to see the result in a pane at the bottom of the page (click on the cross to close it or type Esc on a cell in edit mode).
?log
Complexes exist but the imaginary number is j
and you have to write1j
and not just j
:
1j**2
(-1+0j)
sqrt(1j)
(0.7071067811865476+0.7071067811865476j)
e**(pi*1j)
(-1+1.2246467991473532e-16j)
Note the rounding error in the $e^{i \pi}$ calculation for the imaginary part.
The order of priority of the operators is:
**
the power-x
,+ x
the unit operator minus or plus*
, /
, //
(//
being the entire division)%
the modulo+
, -
print( -3**2 )
print( 9/3*3 )
print( 9/(3*3) )
-9 9.0 1.0
Finally, we check the error messages to correct the code:
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