I have two Arrays:
firstArray=[['AF','AFGHANISTAN'],['AL','ALBANIA'],['DZ','ALGERIA'],['AS','AMERICAN SAMOA']]
secondArray=[[1,'AFGHANISTAN'],[3,'AMERICAN SAMOA']]
So I just need an Array which is like
thirdArray=[[1,'AF'],[3,'AS']]
I tried any(e[1] == firstArray[i][1] for e in secondArray)
It returned me True and false if second element of both array matches. but i don't know how to build the third array.
First, convert firstArray into a dict with the country as the key and abbreviation as the value, then just look up the abbreviation for each country in secondArray using a list comprehension:
abbrevDict = {country: abbrev for abbrev, country in firstArray}
thirdArray = [[key, abbrevDict[country]] for key, country in secondArray]
If you are on a Python version without dict comprehensions (2.6 and below) you can use the following to create abbrevDict:
abbrevDict = dict((country, abbrev) for abbrev, country in firstArray)
Or the more concise but less readable:
abbrevDict = dict(map(reversed, firstArray))
It is better to store them into dictionaries:
firstDictionary = {key:value for value, key in firstArray}
# in older versions of Python:
# firstDictionary = dict((key, value) for value, key in firstArray)
then you could get the 3rd array simply by dictionary look-up:
thirdArray = [[value, firstDictionary[key]] for value, key in secondArray]
You could use an interim dict as a lookup:
firstArray=[['AF','AFGHANISTAN'],['AL','ALBANIA'],['DZ','ALGERIA'],['AS','AMERICAN SAMOA']]
secondArray=[[1,'AFGHANISTAN'],[3,'AMERICAN SAMOA']]
lookup = {snd:fst for fst, snd in firstArray}
thirdArray = [[n, lookup[name]] for n, name in secondArray]
If a dictionary would do, there is a special purpose Counter dictionary for exactly this use case.
>>> from collections import Counter
>>> Counter(firstArray + secondArray)
Counter({['AF','AFGHANISTAN']: 1 ... })
Note that the arguments are reversed from what you requested, but that's easily remedied.
The standard way to match data to a key is a dictionary. You can convert firstArray to a dictionary using dict comprehension.
firstDict = {x: y for (y, x) in firstArray}
You can then iterate over your second array using list comprehension.
[[i[0], firstDict[i[1]]] for i in secondArray]
use a list comprehension:
In [119]: fa=[['AF','AFGHANISTAN'],['AL','ALBANIA'],['DZ','ALGERIA'],['AS','AMERICAN SAMOA']]
In [120]: sa=[[1,'AFGHANISTAN'],[3,'AMERICAN SAMOA']]
In [121]: [[y[0],x[0]] for x in fa for y in sa if y[1]==x[1]]
Out[121]: [[1, 'AF'], [3, 'AS']]
