Bernard Szlachta at 19:20, 6 February 2013

2013-02-06T19:20:26Z

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{{Cat|Python Commands|0010}}
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== Determining the length of sequences ==
The len() functions returns an integer with the length b of an argument. It works with strings, lists, tuples, and dictionaries.

<source lang="python">
l = [0,1,2,3]
print len(l) # → 4
</source>

== Creating lists of integer numbers ==
The range function allows to create lists of numbers on-the-fly. There are two optional parameters for the start value and the step size.

<source lang="python">
l = range(4) # [0,1,2,3]
l = range(1,5) # [1,2,3,4]
l = range(2,9,2) # [2,4,6,8]
l = range(5,0,-1) # [5,4,3,2,1]
</source>

== Summing up numbers ==
The sum of a list of integer or float numbers can be calculated by the sum() function.

<source lang="python">
l = [1,2,3,4]
print sum(l)
</source>

== Enumerating elements of lists ==
The enumerate() function associates an integer number starting from zero to each element in a list. This is helpful in loops where an index variable is required.

<source lang="python">
fruits = ['apple','banana','orange']
for i, fruit in enumerate(fruits):
print i, fruit
</source>

== Merging two lists ==
The zip() function associates the elements of two lists to a single list of tuple. Excess elements are ignored.

<source lang="python">
fruits = ['apple','banana','orange']
prices = [0.55, 0.75, 0.80, 1.23]

for fruit,price in zip(fruits,prices):
print fruit, price
</source>

Built-in functions - Revision history

Bernard Szlachta at 19:20, 6 February 2013