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)

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:

In [51]: a='0' In [52]: b='1' In [53]: 4*a+4*b

Out[53]: '00001111'

In [44]: a=0,1,2,3

In [45]: a*4

Out[45]: (0,1, 2, 3, 0, 1, 2, 3, 0, 1, 2, 3, 0, 1, 2, 3, 0)

Second Solution (in einer Schleife):

a = [range(0,4)]

for item in a:

• b = item * 4
  • b.sort()
    • c = item * 4
      • d = [b,c]
        • 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:

• German Language

• Das Python-Tutorium (Version 1.5.2)

• Beschränkung aufs Wesentliche (iX 11/1999)