Python:Accumulators For Searching Tutorial

Accumulator Tutorials

Adding and Counting

Two Accumulators

Checking an Array

Building Strings

Using a file

Multiple Variables

Searching for Values

Harder Examples

Reprise

The biggest population

What is the population of the largest country (by population).

How to use an accumulator

Recall that there are three steps:

• Declare and initialise your accumulator before the loop starts.

acc = 0

• Update the accumulator inside the loop if appropriate.

  if pop>acc:
    acc = pop

• Use the result - in this case print it, after the loop.

print acc

.

fh = open("cia.txt","r") acc = 0 for line in fh: f = line.split("\t") name = f[0] region = f[1] area = int(f[2]) pop = int(f[3]) gdp = int(f[4]) if area>1500000: acc = acc+1 print acc

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test text

 

 

 

 

Which country has the biggest population?

What is the name of the largest country (by population).

Hint

You will need two variables. One holds the largest population so far, the other holds the name of the largest country so far.

.

fh = open("cia.txt","r") acc = 0 for line in fh: f = line.split("\t") name = f[0] region = f[1] area = int(f[2]) pop = int(f[3]) gdp = int(f[4]) if area>1500000: acc = acc+1 print acc

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test text

 

 

 

 

Which middle eastern country has the smallest population?

What is the name of the country in region "Middle East" with the smallest population.

.

fh = open("cia.txt","r") acc = 0 for line in fh: f = line.split("\t") name = f[0] region = f[1] area = int(f[2]) pop = int(f[3]) gdp = int(f[4]) if area>1500000: acc = acc+1 print acc

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test text

 

 

 

 

Accumulator Tutorials

Adding and Counting

Two Accumulators

Checking an Array

Building Strings

Using a file

Multiple Variables

Searching for Values

Harder Examples

Reprise