Iterating over an array | Python Fiddle

# Tutotial: 
# https://docs.python.org/2/tutorial/datastructures.html#tut-loopidioms

tests = {
         "test-1": {
                    "urls": [ "appurl-1a", "appurl-1b" ],
                    "layers": [ "flayer-1a", "flayer-1b" ]
         },
         "test-2": {
                    "urls": [ "appurl-2a", "appurl-2b" ],
                    "layers": [ "flayer-2a", "flayer-2b" ]
         },
         "test-3": {
                    "urls": [ "appurl-3a", "appurl-3b" ],
                    "layers": [ "flayer-3a", "flayer-3b" ]
         },
         "test-4": {
                    "urls": [ "appurl-4a", "appurl-4b" ],
                    "layers": [ "flayer-4a", "flayer-4b" ]
         }
}

print "\n", "tests defined using an object:"

for testName in tests:
    print "\n", "[ ", testName, " ]"
    
    appUrls = tests[testName]["urls"]
    layerUrls = tests[testName]["layers"]
    
    # One way to iterate over an array:
    print "Looping technique A:"
    
    for url in appUrls:
        print " ", url

# Another way to iterate over an array:
    # This method is better since you get the array index 
    # which you can use to read the corresponding element in
    # layerUrls.
    print "Looping technique B:"
    
    for index, appUrl in enumerate(appUrls):
        print " ", index, appUrl, layerUrls[index]

# This technique works too:
    print "Looping technique C:"
    
    for index in range(len(appUrls)):
        print " ", index, appUrls[index], layerUrls[index]
        
    # This technique is even better:
    print "Looping technique D:"
    
    for appUrl, layerUrl in zip(appUrls, layerUrls):
        print " ", appUrl, layerUrl
        
# Notice the above looping over "tests" does not list tests in the order
# they are defined i.e. test-4 is processed first before 1, 2 and 3.
# If you want to fix this, you need to define tests as an array instead 
# of object:
print "\n=============================="
print "\n", "tests defined using an array:"

# See how the test name is now a property of each test object.
tests2 = [
	{
     	"name": "test-1",
    	"urls": [ "appurl-1a", "appurl-1b" ],
    	"layers": [ "flayer-1a", "flayer-1b" ]
    },
	{
     	"name": "test-2",
    	"urls": [ "appurl-2a", "appurl-2b" ],
    	"layers": [ "flayer-2a", "flayer-2b" ]
    },
	{
     	"name": "test-3",
    	"urls": [ "appurl-3a", "appurl-3b" ],
    	"layers": [ "flayer-3a", "flayer-3b" ]
    },
	{
     	"name": "test-4",
    	"urls": [ "appurl-4a", "appurl-4b" ],
    	"layers": [ "flayer-4a", "flayer-4b" ]
    }
]

for testObj in tests2:
    print "\n", "[ ", testObj["name"], " ]"
    
    appUrls = testObj["urls"]
    layerUrls = testObj["layers"]
    
    # One way to iterate over an array:
    print "Looping technique A:"
    
    for url in appUrls:
        print " ", url

# Another way to iterate over an array:
    # This technique is better since you get the array index 
    # which you can use to read the corresponding element in
    # layerUrls.
    print "Looping technique B:"
    
    for index, url in enumerate(appUrls):
        print " ", index, url, layerUrls[index]

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