使用python遍历列表列表

Question

I have a function that creates a list containing 3 elements and appends this list to a master list called peaks:

peak = (x_data point, y_data point and area)   
peaks = (peak, peak, peak etc)

I am trying to write a loop that cycles through the peak[area] elements and returns the areas that are greater than 100000 and then using this in a matplotlib 'text' to graph input. Here is my code:

plot(x_data, y_data)                          
for peak in peaks:
    if peak[2] >= 100000:
        text(peak[0], 1.02*peak[1], '%d'%int(peak[2]))
grid(True)                 
show()

The output is just the x_data vs y_data plot with no text annotations...any ideas why? I can't figure it out.

This loop works if i exclude the if statement. However, I want to select the peaks with an area greater than 100000.

Answer 1

It appears that the peak areas are reported as negative.

The solution was to change

for peak in peaks:
    if peak[2] >= 100000:
        text(peak[0], 1.02*peak[1], '%d'%int(peak[2]))

to

for peak in peaks:
    if peak[2] <= -100000:
        text(peak[0], 1.02*peak[1], '%d'%int(peak[2]))