Differences between revisions 23 and 25 (spanning 2 versions)

For loops

a)

   1 for i in range(0,4,1):
   2      print i
   3   
   4 0
   5 1 
   6 2
   7 3

Insert an expression in ... to get the results.

Solution:

b)

What are the corresponding loops?

Solution (two in one ;-):

   1 a = [range(0,4)]
   2 for item in a:
   3          b = item * 4
   4          b.sort()
   5          c = item * 4
   6          d = [b,c]
   7          print d

Data types

A=dict([('a',1),('b',2)])

Please specify the data types:

A is a ...
'a' is a ...
1 is a ...
('a',1) is a ...
[('a',1),('b',2)] is a ...

Provide an alternative way to assign A

Scipy numeric types

from scipy import *

One byte consists of eight bit and covers the value range of 0..255 (uint8, unsigned integer) or -128..127.

   1 b=int8(128)
   2 -128 # Invalid range
   3 
   4 b.nbytes
   5 1

a)

What is the value range of the following types and how many bytes are allocated in the memory?

bool8
uint8, int8
uint16, int16
uint32, int32
uint64, uint64

Solution:

b)

How many bytes are allocated in the memory by these floating point types?

float32, float64, float96
complex64, complex128, complex192

Solution:

Data structures

a)

   1 D={'A':array(range(10)),'B':array(range(10))+1}

Which keys contains the dictionary D
Get the keys with the method D.keys()
Display all values of D using the method .values()
Display array A
Display the elements 3:6 of arrays B
Set this elements to 0
Insert a new key-values pair C:array(range(0,10,-1)) into D

Solution:

Reading and practicing

Install python and ipython on your computer and read through the tutorial which comes with the documentation. There are translations in other languages:

-  ⇤ ← Revision 23 as of 2008-11-17 14:18:48 → 
  Size: 2207
  Editor: anonymous
  Comment:
+   ← Revision 25 as of 2008-11-17 14:23:55 → ⇥
  Size: 2538
  Editor: KorFreier
  Comment:
-Deletions are marked like this.
+Additions are marked like this.
 Line 5:
-Line 6:
+Line 8:
-Line 8:
+Line 11:
+{{{#!python
for i in range(0,4,1):
     print i
  
0
1 
2
3
}}}
-Line 9:
+Line 21:
-{{{#!python
+ * Insert an expression in {{{...}}} to get the results.

Solution:

== b) ==
{{{
0 0
0 1
0 2
0 3
1 0
1 1
1 2
1 3
2 0
2 1
2 2
2 3
3 0
3 1
3 2
3 3
}}}

 * What are the corresponding loops?

Solution (two in one ;-):
{{{#!python
-Line 12:
+Line 51:
-         b = item * 4  
         b.sort() 
         c = item * 4 
         d = [b,c] 
         print d
+         b = item * 4
         b.sort()
         c = item * 4
         d = [b,c]
         print d
-Line 19:
+Line 58:
+= Data types =
-Line 20:
+Line 60:
-= Data types =
-Line 26:
+Line 63:
-Line 28:
+Line 66:
-Line 35:
+Line 74:
-Line 37:
+Line 77:
-Line 39:
+Line 80:
-One byte consists of eight bit and covers the value range of 0..255 ({{{uint8}}}, unsigned integer)  or -128..127.
+One byte consists of eight bit and covers the value range of 0..255 ({{{uint8}}}, unsigned integer) 
or -128..127.
-Line 41:
+Line 83:
-{{{
#!python
+{{{#!python
-Line 50:
+Line 90:
-Line 51:
+Line 92:
-Line 61:
+Line 103:
-Line 62:
+Line 105:
-Line 71:
+Line 115:
-{{{
#!python
+{{{#!python
-Line 76:
+Line 118:
-Line 80:
+Line 123:
  * Display the elements {{{3:6}}} of arrays {{{B}}}
-Line 82:
+Line 125:
  * Insert a new key-values pair {{{C:array(range(0,10,-1))}}} into {{{D}}}
-Line 86:
+Line 129:
-Line 87:
+Line 131:
-Line 88:
+Line 133: