Map function takes in two arguments. map function applies the function to all the elements of sequence. It returns a new list (Python 2) with the elements changed by function. Map function returns iterators in Python 3.

**Syntax** –

Map(function,sequence)

**Example**

def fahrenheit(T): return ((float(9)/5)*T + 32) temp = [0, 22.5, 40,100]

F_temps = map(fahrenheit, temp) #Show F_temps

O/P ->

[32.0, 72.5, 104.0, 212.0]Map with Lambda function

map(lambda x: (5.0/9)*(x - 32), F_temps) OR

a = [1,2,3,4] b = [5,6,7,8] c = [9,10,11,12] map(lambda x,y:x+y,a,b)O/P->

[6, 8, 10, 12]

OR

# Now all three lists map(lambda x,y,z:x+y+z, a,b,c)

## Reduce

The function **reduce **continually applies the function to the sequence. **It returns a single value.**

**Syntax**

reduce(function,sequence)

**Example – **

lst =[47,11,42,13] reduce(lambda x,y: x+y,lst)Output 113 Explanation

If seq = [ s1, s2, s3, … , sn ], calling reduce(function, sequence) works like this:

- At first the first two elements of seq will be applied to function, i.e. func(s1,s2)
- The list on which reduce() works looks now like this: [ function(s1, s2), s3, … , sn ]
- In the next step the function will be applied on the previous result and the third element of the list, i.e. function(function(s1, s2),s3)
- The list looks like this now: [ function(function(s1, s2),s3), … , sn ]
- It continues like this until just one element is left and return this element as the result of reduce()

**Example 2**

#Find the maximum of a sequence (This already exists as max()) max_find = lambda a,b: a if (a > b) else b

#Find max reduce(max_find,lst)Output 47

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